Chronicle of a discovery: the retinoic acid receptor

in Journal of Molecular Endocrinology
Authors:
Vincent GiguèreGoodman Cancer Institute, McGill University, Montréal, Quebec, Canada
Department of Biochemistry, McGill University, Montréal, Quebec, Canada

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https://orcid.org/0000-0001-9567-3694
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Ronald M EvansThe Salk Institute for Biological Studies, La Jolla, California, USA

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https://orcid.org/0000-0002-9986-5965

Correspondence should be addressed to V Giguère: vincent.giguere@mcgill.ca

This paper forms part of a special issue marking 35 Years Since the Discovery of the Retinoic Acid Receptor. The guest editors for this section were Simak Ali and Vincent Giguère.

Free access

The landmark 1987 discovery of the retinoic acid receptor (RAR) came as a surprise, uncovering a genomic kinship between the fields of vitamin A biology and steroid receptors. This stunning breakthrough triggered a cascade of studies to deconstruct the roles played by the RAR and its natural and synthetic ligands in embryonic development, skin, growth, physiology, vision, and disease as well as providing a template to elucidate the molecular mechanisms by which nuclear receptors regulate gene expression. In this review, written from historic and personal perspectives, we highlight the milestones that led to the discovery of the RAR and the subsequent studies that enriched our knowledge of the molecular mechanisms by which a low-abundant dietary compound could be so essential to the generation and maintenance of life itself.

Abstract

The landmark 1987 discovery of the retinoic acid receptor (RAR) came as a surprise, uncovering a genomic kinship between the fields of vitamin A biology and steroid receptors. This stunning breakthrough triggered a cascade of studies to deconstruct the roles played by the RAR and its natural and synthetic ligands in embryonic development, skin, growth, physiology, vision, and disease as well as providing a template to elucidate the molecular mechanisms by which nuclear receptors regulate gene expression. In this review, written from historic and personal perspectives, we highlight the milestones that led to the discovery of the RAR and the subsequent studies that enriched our knowledge of the molecular mechanisms by which a low-abundant dietary compound could be so essential to the generation and maintenance of life itself.

Introduction

The precise control of gene expression is a fundamental molecular mechanism essential from the first cell division to the complete development of the organism and its maintenance throughout its lifespan. Cell-specific expression of genes is dependent on the action of transcription factors that transduce extra and intracellular signals into specific biological programs. Indeed, a purified fraction containing a receptor for the hormone cortisol (glucocorticoid receptor, GR) was among the first higher eukaryote transcription factors shown to recognize specific sites on a promoter (Payvar et al. 1981). Shortly thereafter, the GR would become the first full-length human transcription factor molecularly cloned and shown to be necessary and sufficient for the transcriptional activation of a reporter gene when re-introduced into a cell (Hollenberg et al. 1985, Giguère et al. 1986). The rapid subsequent identification of receptors for estradiol, thyroid hormones, aldosterone, progesterone, vitamin D3, and orphan receptors without known ligands, all sharing a common structure and functional domains, led to the surreal concept of a genomic superfamily of ligand-responsive transcription factors and the potential existence of previously unrecognized hormone/metabolites response systems (Evans 1988, Giguère et al. 1988).

Vitamin A, aka all-trans-retinol, was purified by McCollum and Davis (Wisconsin) and Osborne and Mendel (Yale) in 1913 (Semba 2012). They showed it to be a low-abundant dietary fat-soluble compound that is essential for vision, reproduction, embryonic development, immunity as well as the normal growth and preservation of a healthy organism. Vitamin A was shown very early to be essential for normal differentiation and preservation of epithelial tissues (Wolbach & Howe 1925). Nonetheless, it would take several decades of work and many detours along the way to finally answer the question as to how this small nutrient influences cell fate. Below is a brief history of vitamin A and of the unanticipated discovery that its receptor would be a member of the nuclear receptor family now referred to as the retinoic acid receptor (RAR) (Giguère et al. 1987). A companion article in this commemorative issue describes the contemporaneous identification of the RAR by the team of Pierre Chambon in Strasbourg (Petkovich et al. 1987).

Vitamin A

The concept that animals could thrive when fed suitable food like milk but not its separated components (proteins, fats, carbohydrates, salts, and water) led to the suggestion by Nicolai Lunin in 1881 that additional elements indispensable for nutrition must exist in foodstuff (Lunin 1881). A few years later, Frederick Hopkins reiterated in a lecture in London that unsuspected dietary factors other than proteins, fat, carbohydrates, and minerals were present in food and intuited that the lack of these factors could be linked to ailments such as scurvy and rickets (Hopkins 1906). In a landmark study published in 1912, Hopkins then demonstrated that the growth of mice was indeed dependent on accessory factors present in milk in very small amounts, but the composition of these accessory factors was unknown (Hopkins 1912). The term ‘fat-soluble A’ was introduced in 1918 by Elmer McCollum to describe an accessory food factor necessary for general growth and preserving vision (McCollum et al. 1918). The name vitamin A was subsequently introduced by Jack Drummond at University College, London, as part of a new nomenclature to classify a growing list of dietary factors of different chemical compositions as vital factors, ergo ‘vitamins’ (Drummond 1920). Hopkins and Christiaan Eijkman, who concurrently discovered the antineuric vitamin (now known as thiamin or vitamin B1) while studying the cause of the diet-deficiency disease beriberi, were awarded the Nobel Prize in Physiology and Medicine in 1929 for ‘the discovery of the vitamins.’ Two more Nobel Prizes were later awarded for work related to vitamin A, one for determining the chemical structure of vitamin A to Paul Karrer (1937, Nobel Prize in Chemistry) and a second to George Wald who discovered that the vitamin A metabolite all-trans-retinal is a crucial component in rhodopsin and thus necessary for vision (1967, Nobel Prize in Physiology and Medicine). The development of the large-scale synthesis of vitamin A by chemists at Hoffman-La Roche in the 1940s allowed for the effective treatment and prevention of vitamin A deficiency-related diseases, including impaired immunity and hematopoiesis, xerophthalmia, and night blindness.

All-trans-retinoic acid

The pro-vitamin β-carotene and vitamin A, itself present in the diet, are inactive compounds that must be metabolized by the organism to all-trans-retinoic acid (at-RA) to sustain vision and cell differentiation, respectively. Indeed, while a role for vitamin A in promoting cellular differentiation was demonstrated early in the characterization of the surprisingly diverse biological properties of the vitamin (Wolbach & Howe 1925), several decades passed before at-RA was identified as the active metabolite of vitamin A responsible for observable changes in cell phenotype. In fact, at-RA was synthesized years before the determination of its unique properties on cell differentiation (Arens & Van Dorp 1946a ). However, it was established at that time that at-RA could sustain normal growth but not reproduction and vision in rats fed a vitamin A-deficient diet and that at-RA could not be converted back into retinol by the liver (Arens & Van Dorp 1946b , Van Dorp & Arens 1946). These experiments thus established that at-RA was an active metabolite with biological activity independent of retinol. In 1967, the group of Hector DeLuca showed that at-RA was formed in vivo in rats injected with 14C-retinol (Emerick et al. 1967), and a few years later, the same team demonstrated that at-RA was indeed a natural metabolite of retinol (Ito et al. 1974). The next key advance in the field came when at-RA was shown as the most potent vitamin A metabolite to induce multiple phenotypic changes in F9 teratocarcinoma stem cells in culture (Strickland & Mahdavi 1978). The at-RA-induced differentiation of cultured F9 embryonal carcinoma cells into endoderm was accompanied by an increase in the synthesis of collagen-like proteins. This at-RA regulated cell system soon became a favored standard model to study the induction of protein synthesis (Chytil 1986). However, the initial observations on the effect of at-RA on cell differentiation made in F9 cells were quickly expanded to other cultured cell systems including neuroblastomas, melanomas, fibroblasts as well as the HL60 promyelocytic leukemia (PML) cell line that could be induced to differentiate into granulocytes (Breitman et al. 1980, Schroder et al. 1982, Haussler et al. 1983, Lotan et al. 1983).

Subsequently, at-RA-inducible genes encoding various keratins were cloned (Eckert & Green 1984, Gilfix & Eckert 1985, Wang et al. 1985), consolidating the hypothesis put forward earlier by Sporn & Roberts (1983) that the action of at-RA could be mediated via changes in gene expression. Several molecular mechanisms underlying the activity of at-RA as potential regulators of gene expression were being investigated at that time. Those included modification of membrane structure, sugar transfer reactions by means of the intermediate retinyl phosphate mannose, direct interactions with protein kinases, cooperation with growth factors through unknown mechanisms, and most prominently, control of gene expression by small cellular retinoic acid-binding proteins (CRABPs) (Chytil & Ong 1979, Sporn & Roberts 1983, Chytil 1986). CRABPI, a small cytoplasmic protein with a molecular weight of 14,500 daltons, was initially purified by Ong and Chytil from rat testis for its ability to bind 14C-at-RA (Ong & Chytil 1978). A complementary cDNA encoding CRABPI was cloned and its sequence confirmed the small size of the protein and incorrectly suggested its possible role as a transcriptional regulator (Shubeita et al. 1987). A second CRABP isoform, referred to as CRABPII, was subsequently identified by molecular cloning and its expression was found to be highly inducible by at-RA, consolidating a possible function for CRABPs in transmitting the at-RA signal (Giguère et al. 1990a ). However, despite decades of ensuing investigation on the potential roles played by CRABPs in at-RA biological activities, the exact function of the two CRABP isoforms remains to be fully uncovered.

Discovery of the RAR

Our discovery of the RAR (Giguère et al. 1987), later referred to as RARα, was enabled by a confluence of specialized expertise within the lab and the rapid evolution of our knowledge of nuclear receptors and how they work. During a 2-year window, this project evolved over seven brisk steps, each briefly summarized below.

Cloning of the GR and its homology to v-erbA

The recognition that the GR shared sequence homology and structural relationship with the RNA tumor virus v-erbA suggested an unforeseen kinship between a steroid receptor and a viral protooncogene (Hollenberg et al. 1985, Weinberger et al. 1985). These observations were validated a few months later by simultaneous publications reporting the cloning of the estrogen receptor (ER) by the teams of Pierre Chambon and Geoffrey Greene (Green et al. 1986, Greene et al. 1986). The oncogene v-erbA became the focus of both Weinberger and Bjorn Vennstrom, a world expert in RNA leukemia viruses. The successful discovery of the human and avian homolog of the verbA oncogenes led to its exciting discovery as the thyroid hormone (T3R) (Sap et al. 1986, Weinberger et al. 1986). This set of experiments helped to launch a new era in receptor discovery and function with the mindful notion that newly discovered nuclear receptors need not necessarily have to bind or respond to steroids.

The ‘co-transfection assay’

The cloning of the GR led us to develop new techniques, the first of which was the ‘co-transfection assay.’ The goal behind the co-transfection assay was to reconstitute a functional hormonal response in cells to characterize the molecular mechanisms underlying nuclear receptor signaling. To address this, we transfected cells with two separate plasmids pairing an hGR cDNA expression plasmid with a glucocorticoid-responsive reporter gene (Giguère et al. 1986). The chosen reporter was the gene encoding the bacterial enzyme chloramphenicol acetyltransferase (CAT). The CAT assay had originally been developed to monitor the transcriptional activity of the long terminal repeat (LTR) of the Rous sarcoma virus (RSV) (Gorman et al. 1982). One of us (V G) had the opportunity to obtain the pRSV-CAT construct in 1984 directly from Dr Gorman who was at that time at the same institution, the National Institute for Medical Research at Mill Hill, England. In London, I (V G) modified the pRSV-CAT construct by replacing the sequence of the RSV LTR with the promoter of the gene encoding the mouse Thy-1 antigen and used this construct to demonstrate that a GC-rich/TATAA box-less mammalian promoter could efficiently drive gene expression (Giguère et al. 1985). At the Salk Institute in La Jolla, the original pRSV-CAT construct was then modified to build two vectors to create the co-transfection assay. The first vector was used to express a transcription factor and the second, a reporter gene whose expression would be dependent on the transcription factor expressed by the first vector. To generate the first vector, the CAT gene in pRSV-CAT was replaced by the cDNA encoding the human GR to generate high levels of expression of the receptor. The second vector included the glucocorticoid-responsive regulatory region of mouse mammary tumor virus that had been previously shown to confer potent hormone responsiveness to a heterologous promoter (Chandler et al. 1983). The co-transfection of the two expression plasmids resulted in a very impressive hormone-dependent transcriptional response allowing for the rapid analysis of multiple aspects of the hormonal activation, for example, ligand potency and specificity, characterization of hormone response elements (HREs) within regulatory regions of genes, studies of structure–function relationship within nuclear receptors, and the interaction and dependency of nuclear receptors on co-regulatory proteins and the general transcription machinery. Indeed, the co-transfection assay was so adaptable as a cell-based platform to study gene transcription that it rapidly became (and remains) one of the most indispensable and widely used assays in molecular biology. It also rapidly became an indispensable screening tool in the pharmaceutical industry, underpinning the development of a panoply of new nuclear receptor-directed therapeutics (Evans & Mangelsdorf 2014).

Functional domains of nuclear receptors

The co-transfection assay proved to be crucial in localizing and characterizing the hGR functional domains. To address the question of domain structure, we created a series of plasmids harboring mutations scattered throughout the hGR sequence. These mutant GR plasmids were generated via insertion (or deletion) of three or four extraneous amino acids, an improvement on the approach previously exploited to identify functional regions in the transforming protein of Fujinami sarcoma virus (Stone et al. 1984). An in-depth analysis of these mutant proteins allowed us to assemble a detailed model of the GR and its functional domains (Giguère et al. 1986). The model revealed that the GR protein architecture is comprised of an ensemble of discrete functional domains responsible for ligand-binding, DNA-binding, and transcriptional activation. This model was quickly validated by studies on the human ER and rat GR (Kumar et al. 1987, Miesfeld et al. 1987). The independence of each functional domain within the receptor led to the proposal that functional domains could be switched between related proteins (Giguère et al. 1986). Swapping domains between receptors was then successively shown to generate functional hybrid nuclear receptors (Green & Chambon 1987) and to confer hormone-responsiveness, or a transcriptional switch, to otherwise constitutive transcription factors (Picard et al. 1988, Eilers et al. 1989). The distinctiveness, but at the same time, the interdependence of each nuclear receptor functional domain, was subsequently depicted in great detail by crystallographic and cryoelectron microscopy studies (Chandra et al. 2008, 2013, Yu et al. 2020).

Multiple genetic loci related to nuclear receptors

Low stringency hybridization studies using genomic DNA indicated the existence of multiple genetic loci that hybridized with the cDNA clones encoding the T3R, GR, and ER. It was thus realized that the close homology between the DNA sequences encoding different nuclear receptors could be exploited to clone additional receptors related to these sequences, especially receptors for other cholesterol-derived steroid hormones such as progesterone, androgens, aldosterone, and vitamin D3. Low stringency homology screening led in rapid succession to the cloning of the mineralocorticoid receptor (Arriza et al. 1987), a second T3R isoform (TRβ) (Thompson et al. 1987) and two clones encoding receptors with homology to the ER, originally named estrogen-related receptor 1 and 2 (ERR1 and 2) (Giguère et al. 1988). No known hormone or other small ligands could be shown to bind to the ERRs, which thus became the first ‘orphan nuclear receptors’ to be inducted into the superfamily. Members of the ERR subfamily of nuclear receptors are now known as master regulators of cellular energy metabolism but remain classified as orphan receptors 35 years later (Scholtes & Giguère 2022). We discuss ERR cloning above in 1988 but we have now to go backward to 1986 for the RAR/hepatitis B virus challenge described below.

The hepatitis B virus integration site

In addition to the discovery of multiple genetic loci with sequence similarity with nuclear receptors, Anne Dejean (Dejean 1986) reported that a hepatitis B virus (HBV) integration into human liver DNA placed the viral sequence next to a sequence with striking homology to both the oncogene v-erbA and the DNA-binding domain (DBD) of the human GR and ER. In early in 1986, several candidate steroid hormone receptors remained to be cloned (e.g. androgen, progesterone, and aldosterone). I (V G) decided to ‘throw my hat in the ring’ and capture the HBV associated as a possible new nuclear receptor. The race thus promptly started to clone the corresponding full-length cDNA and identify a hormone ligand associated with this putative receptor.

An unexpected twist

A strategy to clone the cDNA transcribed from the gene disrupted by the HBV integration was conceived. First, we synthesized a long oligonucleotide containing the sequence of the exon encoding a segment of the putative nuclear receptor. The oligonucleotide was then labeled and used as a probe to screen a number of human cDNA libraries. Several clones were obtained and the longest contained ~2900 base pairs that could be translated into an open reading frame of 462 amino acids which could easily encode a full-length nuclear receptor (Giguère et al. 1987). Indeed, comparison of the amino acid sequence of this receptor ‘X’ with GR and both T3Rs showed that the highest degree of similarity was found in a cysteine-rich sequence of 66 amino acids encoding the DBD of nuclear receptors. However, the nucleotide sequence encoding this segment of the cDNA, while displaying strong homology with the published sequence of the HBV integration site (Dejean et al. 1986), was not a perfect match. In addition, the hybridization pattern of genomic DNA obtained with our cDNA clone was unrelated to the restriction enzyme map previously described by Dejean for the HBV integration site. By relaxing the stringency of the hybridization to genomic DNA, we then confirmed the existence of two or more loci related to this cDNA, including the original HBV integration site. We thus had cloned a full-length cDNA encoding a novel nuclear receptor but not the one we intended to obtain using the probe derived from the HBV integration site.

A eureka moment

As the ligand for the gene product of receptor X was unknown, we modified the co-transfection assay into a sensitive screening tool to reveal its identity. As mentioned above, the DBDs of the human GR and ER had been shown to be interchangeable, resulting in functional hybrid nuclear receptors (Green & Chambon 1987). This observation suggested a more general strategy that could be exploited to identify the potential ligand associated with the presumptive novel hormone receptor. We thus swapped the DBD of the gene product encoded by the cDNA described in the previous section with the DBD from the human GR, expecting that the hybrid receptor would induce the activity of the MMTV-CAT reporter gene in response to an appropriate ligand. The dual plasmid co-transfection assay enabled us to challenge the hybrid receptor with a battery of 12 candidate ligands that included at-RA (Fig. 1). In a dramatic eureka moment never to be forgotten on a beautiful Sunday morning in La Jolla, the result of a co-transfection assay revealed that only at-RA could elicit a powerful increase in CAT activity in the presence of the hybrid receptor (Giguère et al. 1987). All other natural and synthetic ligands included in the screen, namely aldosterone, dexamethasone, dihydrotestosterone, estrogen, progesterone, triiodothyronine (T3), thyroxine , vitamin D3, and 25-OH-cholesterol, did not elicit CAT activity. The identity of the novel gene product as the receptor for at-RA was then validated by its capacity to specifically bind to radiolabeled at-RA. We had suddenly discovered a receptor for at-RA that is now part of the family of steroid and thyroid hormone receptors. This sudden advance disrupted the field of vitamin A biology, opening entirely new directions in understanding how this simple vitamin can have such a vast impact on cellular function and body physiology.

Figure 1
Figure 1

Schematic representation of the strategy leading to the discovery of the retinoic receptor (RAR). Top: schematic representation of the construction of the hybrid receptor. The main functional domains of the receptors are indicated by DBD (DNA-binding) and LBD (ligand-binding). The LBDs also indicate the identity of the natural ligand of each parent receptor. The cDNAs encoding each receptor were mutated to introduce novel restriction enzyme sites (Not1 and Xho1) bordering the DBD. The mutations did not modify the amino acid sequence of each parent receptor. The DBD of the RAR was then switch for the DBD of the glucocorticoid receptor (GR), generating a hybrid receptor (RGR) now able to recognize the glucocorticoid response element (GRE) located within the mouse mammary tumor virus (MMTV) long terminal repeat (LTR). The reporter plasmid consisted in the MMTV-LTR driving the expression of the bacterial gene encoding the enzyme chloramphenicol acetyl transferase (CAT). The hybrid RGR construct as well as the two parent receptors (GR and RAR as positive and negative controls, respectively) were then independently co-transfected into CV-1 cells together with the MMTV-CAT reporter plasmid. Bottom: schematic representation of the result of the original CAT assay performed with extracts obtained from co-transfected cells challenged with a series of putative ligands. The assay revealed in a singular eureka moment that at-RA (RA) was the only ligand eliciting a powerful increase in CAT activity in the presence of the hybrid receptor RGR. A receptor for at-RA had been discovered. A, aldosterone; AC, acetyl chloramphenicol; C, chloramphenicol; OHC, 25-hydroxy-cholesterol; D, dihydrotestosterone; DEX, dexamethasone; E2, estradiol; P, progesterone; RA, all-trans-retinoic acid; T3, triiodothyronine; T4, thyroxine; VD3, vitamin D3.

Citation: Journal of Molecular Endocrinology 69, 4; 10.1530/JME-22-0117

A family of retinoic acid receptors

Over the next 2 years, two additional receptors responsive to at-RA were rapidly identified and referred to as RARβ and RARγ (Brand et al. 1988, Krust et al. 1989, Zelent et al. 1989). Several isoforms of the three RARs harboring distinct amino-terminal domains were subsequently identified in human and mouse (Giguère et al. 1990b , Kastner et al. 1990, Leroy et al. 1991, Zelent et al. 1991, Nagpal et al. 1992). Genes encoding evolutionary conserved RARs were found in a variety of other species such as chicken (Smith & Eichele 1991), frog (Ellinger-Ziegelbauer & Dreyer 1991), and newt (Giguère et al. 1989, Ragsdale et al. 1989, Ragsdale et al. 1992) but not in invertebrates.

The sustained pursuit to associate ligands with newly cloned orphan nuclear receptors channeled the Evans team to the discovery of a second retinoid-responsive system. David Mangelsdorf (Mangelsdorf 1990) showed that the activity of an orphan receptor referred to as RXR could be induced by pharmacological concentrations of at-RA. In a genomic organization similar to that of the RARs, three distinct genes encoding RXR isoforms (α, β, γ) were identified in mouse and human (Hamada et al. 1989, Mangelsdorf et al. 1990, 1992, Fleischhauer et al. 1992, Leid et al. 1992). A search for a higher affinity retinoid for RXR led to the identification of the 9-cis isomer of RA (9-cis-RA) as a suitable ligand (Heyman et al. 1992, Levin et al. 1992). Given its low abundance in tissues and high affinity of the RARs, the exact role that endogenous 9-cis-RA plays as an RXR ligand in retinoid signaling in vivo has remained elusive. However, it has recently been reported that a retinoid related to 9-cis-RA present at high endogenous levels in mice, namely 9-cis-13-14-dihydroretinoic acid, binds and transactivates all three RXRs at physiological concentrations (Ruhl et al. 2015).

Gene regulation by the RARs

Another outcome of the discovery of the RAR was the recognition that HREs, initially found to be configured as inverted repeats (i.e. palindromes), can, for a new class of receptors, be composed of tandem response elements termed direct repeats. The characterization of the first at-RA response element (referred to as RARE) was present in the promoter of the RARβ receptor itself. Specifically, it contained two tandem repeats of the sequence PuGGTCA separated by five base pairs (de Thé et al. 1990b , Hoffman et al. 1990, Sucov et al. 1990, Näär et al. 1991). This finding led to a re-examination of the configuration of HREs implicated in the response to T3 and vitamin D3 (Näär et al. 1991, Umesono et al. 1991). Detailed mutational analyses of a wide variety of HREs by Kazuhiko Umesono (Umesono 1991) demonstrated that spacing of direct repeats (DRs) is receptor-specific. Thus, tandem repeats spaced by three, four, or five base pairs were selective HREs for the T3Rs, vitamin D3 receptor, and RAR, respectively. This organizational scheme for the HREs is referred to as the ‘3-4-5 rule.’ The functional relevance of the RARE was quickly shown by the observation that this response element could direct specific spatial and temporal expression of an indicator transgene during mouse embryogenesis, mimicking the expression of the RARβ2 itself (Rossant et al. 1991). Remarkably, the transgene was not only expressed in a specific anterior–posterior domain, but the observed specific expression in the embryo was completely obliterated by treatment of pregnant mice with teratogenic doses of at-RA. These results demonstrated that teratogenesis induced by retinoids were due to ectopic activation of at-RA-responsive genes outside of the normal domains of action of at-RA during development. This mouse model soon became the reference to study the effects of manipulating the at-RA response pathway in vivo on embryonic development via genetic alterations or pharmacological interventions with natural and synthetic retinoids. The list of genes directly regulated by the RARs expanded rapidly thereafter, and molecular and functional characterization of multiple RAREs showed RARs could additionally bind to a variety of half-site configurations, including DR-1, DR-2, and DR-5 response elements (reviewed in Giguère 1994).

A second unanticipated outcome of the discovery of the RARs and RXRs was that the transcriptional activity of members of the two distinct retinoid receptor subfamilies was mechanistically linked. The presence of RXR was found to be absolutely essential for high-affinity binding of RAR to DNA and induction of transactivation by RAR (Yu et al. 1991, Bugge et al. 1992, Kliewer et al. 1992, Leid et al. 1992, Marks et al. 1992, Zhang et al. 1992). The binding of the RXR/RAR heterodimer was then shown to be strictly ordered when bound to direct repeats, RXR occupying the 5’-upstream half-site and RAR the 3’-downstream half-site on both DR-2 and DR-5 RAREs (Kurokawa et al. 1993, Perlmann et al. 1993, Predki et al. 1994). The three RXRs were then shown to not only operate as accessory factors for the RARs but, remarkably, also function as partners for a large contingent of the superfamily of nuclear receptors, particularly for adopted orphan receptors (reviewed in Evans & Mangelsdorf 2014).

RARs and cancer

As discussed above, vitamin A and retinoids were known to be essential for normal development and the maintenance of a healthy organism. In particular, retinoids were well known to have the ability to suppress the development of the malignant phenotype in vitro (Sporn & Roberts 1983). The finding that disruption of the RARβ gene by integration of HBV in its loci could be a factor in the development of human hepatocellular carcinoma provided the first evidence potentially linking a mutation in a RAR gene and cancer (Dejean et al. 1986, Brand et al. 1988). However, the most stunning breakthrough came from the discovery that the characteristic t(15:17) translocation breakpoint observed in acute promyelocytic leukemia was within the locus encoding RARα (Borrow et al. 1990, de Thé et al. 1990a , Longo et al. 1990, Alcalay et al. 1991). The reciprocal translocation resulted in the generation of the expression of novel chimeric proteins comprised of the fusion of PML to RARa (de Thé et al. 1991, Kakizuka et al. 1991). These findings occurred just after the remarkable clinical observation that complete remission of acute promyelocytic leukemia patients could often be achieved by treatment with high doses of at-RA (Huang et al. 1988, Castaigne et al. 1990, Degos et al. 1990). Despite the expectation that at-RA could be used to induce the differentiation of cancer cells in cultured cells, the success of treating acute promyelocytic leukemia with at-RA did not immediately translate to other types of cancer (Singletary et al. 2002, Chiesa et al. 2007) but as discussed below multiple new cancer studies look very promising. For a short time, concerns arose, as retinoids potentiated tumor growth in certain mouse models and human patients (Omenn et al. 1996, Mikkelsen et al. 1998, Albright et al. 2004, Mollersen et al. 2004). However, the widespread use of oral at-RA (isotretinoin) shows very high safety.

As discussed above, 9-cis-RA, an active metabolite of vitamin A, was discovered by the Evans and Levin labs to be a high-affinity ligand for both RXR and RAR (Heyman et al. 1992, Levin et al. 1992). It is approved for use in T-cell lymphoma in people who are refractory to at least one prior systemic therapy (oral) and for the topical treatment of cutaneous lesions in patients with cutaneous T-cell lymphoma (CTCL) who have refractory or persistent disease after other therapies or who have not tolerated other therapies (topical). It is also used ‘off label’ for non-small cell lung cancer and breast cancer (Esteva et al. 2003, Dragnev et al. 2007). In addition, a recent phase 1 clinical trial has shown that at-RA is a potent stromal targeting agent in pancreatic cancer and is now entering phase 2 status (Kocher et al. 2020, Mere Del Aguila et al. 2022).

Epilogue

The discovery 35 years ago of the RAR by Giguère and Evans (Fig. 2) was the conclusion of a very long scientific odyssey that originated with the study of diseases and high mortality rate afflicting poorly fed infants in Paris in the early part of the 19th century (Semba 2012). Incremental work over decades led to the discovery of the vitamins, their synthesis, and eventually their mechanism of action. The discovery of the RAR occupies a singular place in this journey. First, because it solves an 8-decade mystery of how vitamin A achieves its vital impact in the body. Secondly, it is rare that a discovery can so expeditiously directly contribute to therapeutic applications from acne to a deadly disease such as acute promyelocytic leukemia. Thirdly, the three RARs soon became primary conduits of new science, not solely on vitamin A as an essential nutrient for life but in fields as diverse as embryonic development, reproduction, neurobiology, immunology, skin diseases, pharmacology, drug design, and cancer biology. Finally, ending on a promising note, the highly successful drug combination used to treat PML in patients (at-RA + arsenic trioxide) has shown great potential in the treatment of pancreatic cancer (Koikawa et al. 2021). We are thus convinced that an unexpected discovery made 30 years ago has a strong future ahead.

Figure 2
Figure 2

The authors a few months after the discovery of the RAR. Left, Vincent Giguère; right, Ronald M Evans. August 1988, La Jolla, California.

Citation: Journal of Molecular Endocrinology 69, 4; 10.1530/JME-22-0117

Declaration of interest

The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of this review.

Funding

This work did not receive any specific grant from any funding agency in the public, commercial, or not-for-profit sector.

Acknowledgements

The authors wish to acknowledge the huge technical contribution of the co-authors of the original 1987 publication of the discovery of the RAR, Estelita Ong and Prudimar Segui.

References

  • Albright CD, Salganik RI & Van Dyke T 2004 Dietary depletion of vitamin E and vitamin A inhibits mammary tumor growth and metastasis in transgenic mice. Journal of Nutrition 134 11391144. (https://doi.org/10.1093/jn/134.5.1139)

    • Search Google Scholar
    • Export Citation
  • Alcalay M, Zangrilli D, Pandolfi PP, Longo L, Mencarelli A, Giacomicci A, Rocchi M, Biondi A, Rambaldi A & Coco FL 1991 Translocation breakpoint of acute promyelocytic leukemia lies within the retinoic acid receptor a locus. PNAS 88 19771981. (https://doi.org/10.1073/pnas.88.5.1977)

    • Search Google Scholar
    • Export Citation
  • Arens JF & Van Dorp DA 1946a Synthesis of some compounds possessing vitamin A activity. Nature 157 190. (https://doi.org/10.1038/157190a0)

  • Arens JF & Van Dorp DA 1946b Activity of vitamin A-acid in the rat. Nature 158 622. (https://doi.org/10.1038/158622c0)

  • Arriza JL, Weinberger C, Cerelli G, Glaser TM, Handelin BL, Housman DE & Evans RM 1987 Cloning of human mineraloccorticoid receptor complementary DNA: structural and functional kinship with the glucocorticoid receptor. Science 237 268275. (https://doi.org/10.1126/science.3037703)

    • Search Google Scholar
    • Export Citation
  • Borrow J, Goddard AD, Sheer D & Solomon E 1990 Molecular analysis of acute promyelocytic leukemia breakpoint cluster region on chromosome 17. Science 249 15771580. (https://doi.org/10.1126/science.2218500)

    • Search Google Scholar
    • Export Citation
  • Brand N, Petkovich M, Krust A, Chambon P, de Thé H, Marchio A, Tiollais P & Dejean A 1988 Identification of a second human retinoic acid receptor. Nature 332 850853. (https://doi.org/10.1038/332850a0)

    • Search Google Scholar
    • Export Citation
  • Breitman TR, Selonick SE & Collins SJ 1980 Induction of differentiation of the human promyelocytic leukemia cell line (HL-60) by retinoic acid. PNAS 77 29362940. (https://doi.org/10.1073/pnas.77.5.2936)

    • Search Google Scholar
    • Export Citation
  • Bugge TH, Pohl J, Lonnoy O & Stunnenberg HG 1992 RXRa, a promiscuous partner of retinoic acid and thyroid hormone receptors. EMBO Journal 11 14091418. (https://doi.org/10.1002/j.1460-2075.1992.tb05186.x)

    • Search Google Scholar
    • Export Citation
  • Castaigne S, Chomienne C, Daniel MT, Ballerini P, Berger R, Fenaux P & Degos L 1990 All-trans retinoic acid as a differentiation therapy for acute promyelocytic leukemia. I. Clinical results. Blood 76 17041709.

    • Search Google Scholar
    • Export Citation
  • Chandler VL, Maler BA & Yamamoto KR 1983 DNA sequences bound specifically by glucocorticoid receptor in vitro render a heterologous promoter hormone responsive in vivo. Cell 33 489499. (https://doi.org/10.1016/0092-8674(8390430-0)

    • Search Google Scholar
    • Export Citation
  • Chandra V, Huang P, Hamuro Y, Raghuram S, Wang Y, Burris TP & Rastinejad F 2008 Structure of the intact PPAR-γ-RXR-α nuclear receptor complex on DNA. Nature 456 350356. (https://doi.org/10.1038/nature07413)

    • Search Google Scholar
    • Export Citation
  • Chandra V, Huang P, Potluri N, Wu D, Kim Y & Rastinejad F 2013 Multidomain integration in the structure of the HNF-4α nuclear receptor complex. Nature 495 394398. (https://doi.org/10.1038/nature11966)

    • Search Google Scholar
    • Export Citation
  • Chiesa MD, Passalacqua R, Michiara M, Franciosi V, Di Costanzo F, Bisagni G, Camisa R, Buti S, Tomasello G & Cocconi G et al.2007 Tamoxifen vs tamoxifen plus 13-cis-retinoic acid vs tamoxifen plus interferon alpha-2a as first-line endocrine treatments in advanced breast cancer: updated results of a phase II, prospective, randomised multicentre trial. Acta Biomedica 78 204209.

    • Search Google Scholar
    • Export Citation
  • Chytil F 1986 Retinoic acid: biochemistry and metabolism. Journal of the American Academy of Dermatology 15 741747. (https://doi.org/10.1016/s0190-9622(8670229-6)

    • Search Google Scholar
    • Export Citation
  • Chytil F & Ong DE 1979 Cellular retinol- and retinoic acid-binding proteins in vitamin A action. Federation Proceedings 38 25102514.

  • de Thé H, Chomienne C, Lanotte M, Degos L & Dejean A 1990a The t(15;17) translocation of acute promyelocytic leukemia fuses the retinoic acid receptor a gene to a novel transcribed locus. Nature 347 558561. (https://doi.org/10.1038/347558a0)

    • Search Google Scholar
    • Export Citation
  • de Thé H, del Mar Vivanco-Ruiz M, Tiollais P, Stunneberg H & Dejean A 1990b Identification of a retinoic acid responsive element in the retinoic acid receptor β gene. Nature 343 177180. (https://doi.org/10.1038/343177a0)

    • Search Google Scholar
    • Export Citation
  • de Thé H, Lavau C, Marchio A, Chomienne C, Degos L & Dejean A 1991 The PML-RARa fusion mRNA generated by the t(15;17) translocation in acute promyelocytic leukemia encodes a functionally altered RAR. Cell 66 675684. (https://doi.org/10.1016/0092-8674(9190113-d)

    • Search Google Scholar
    • Export Citation
  • Degos L, Chomienne C, Daniel MT, Berger R, Dombret H, Fenaux P & Castaigne S 1990 Treatment of first relapse in acute promyelocytic leukaemia with all-trans retinoic acid. Lancet 336 14401441. (https://doi.org/10.1016/0140-6736(9093135-c)

    • Search Google Scholar
    • Export Citation
  • Dejean A, Bougueleret L, Grzeschik KH & Tiollais P 1986 Hepatitis B virus DNA integration in a sequence homologous to v-erb-A and steroid receptor genes in a hepatocellular carcinoma. Nature 322 7072. (https://doi.org/10.1038/322070a0)

    • Search Google Scholar
    • Export Citation
  • Dragnev KH, Petty WJ, Shah SJ, Lewis LD, Black CC, Memoli V, Nugent WC, Hermann T, Negro-Vilar A & Rigas JR et al.2007 A proof-of-principle clinical trial of bexarotene in patients with non-small cell lung cancer. Clinical Cancer Research 13 17941800. (https://doi.org/10.1158/1078-0432.CCR-06-1836)

    • Search Google Scholar
    • Export Citation
  • Drummond JC 1920 The nomenclature of the so-called accessory food factors (vitamins). Biochemical Journal 14 660. (https://doi.org/10.1042/bj0140660)

    • Search Google Scholar
    • Export Citation
  • Eckert RL & Green H 1984 Cloning of cDNAs specifying vitamin A-responsive human keratins. PNAS 81 43214325. (https://doi.org/10.1073/pnas.81.14.4321)

    • Search Google Scholar
    • Export Citation
  • Eilers M, Picard D, Yamamoto KR & Bishop JM 1989 Chimeras of Myc oncoprotein and steroid receptors cause hormone-dependent transformation of cells. Nature 340 6668. (https://doi.org/10.1038/340066a0)

    • Search Google Scholar
    • Export Citation
  • Ellinger-Ziegelbauer H & Dreyer C 1991 A retinoic acid receptor expressed in the early development of Xenopus laevis. Genes and Development 5 94104. (https://doi.org/10.1101/gad.5.1.94)

    • Search Google Scholar
    • Export Citation
  • Emerick RJ, Zile M & DeLuca HF 1967 Formation of retinoic acid from retinol in the rat. Biochemical Journal 102 606611. (https://doi.org/10.1042/bj1020606)

    • Search Google Scholar
    • Export Citation
  • Esteva FJ, Glaspy J, Baidas S, Laufman L, Hutchins L, Dickler M, Tripathy D, Cohen R, DeMichele A & Yocum RC et al.2003 Multicenter phase II study of oral bexarotene for patients with metastatic breast cancer. Journal of Clinical Oncology 21 9991006. (https://doi.org/10.1200/JCO.2003.05.068)

    • Search Google Scholar
    • Export Citation
  • Evans RM 1988 The steroid and thyroid hormone receptor superfamily. Science 240 889895. (https://doi.org/10.1126/science.3283939)

  • Evans RM & Mangelsdorf DJ 2014 Nuclear receptors, RXR, and the big bang. Cell 157 255266. (https://doi.org/10.1016/j.cell.2014.03.012)

  • Fleischhauer K, Park JH, DiSanto JP, Marks M, Ozato K & Yang SY 1992 Isolation of a fulllength cDNA clone encoding a N-terminally variant form of the human retinoid X receptor β. Nucleic Acids Research 20 1801. (https://doi.org/10.1093/nar/20.7.1801)

    • Search Google Scholar
    • Export Citation
  • Giguère V 1994 Retinoic acid receptors and cellular retinoid binding proteins: complex interplay in retinoid signaling. Endocrine Reviews 15 6179. (https://doi.org/10.1210/edrv-15-1-61)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Isobe K & Grosveld F 1985 Structure of the murine Thy-1 gene. EMBO Journal 4 20172024. (https://doi.org/10.1002/j.1460-2075.1985.tb03886.x)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Hollenberg SM, Rosenfeld MG & Evans RM 1986 Functional domains of the human glucocorticoid receptor. Cell 46 645652. (https://doi.org/10.1016/0092-8674(8690339-9)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Ong ES, Segui P & Evans RM 1987 Identification of a receptor for the morphogen retinoic acid. Nature 330 624629. (https://doi.org/10.1038/330624a0)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Yang N, Segui P & Evans RM 1988 Identification of a new class of steroid hormone receptors. Nature 331 9194. (https://doi.org/10.1038/331091a0)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Ong ES, Evans RM & Tabin CJ 1989 Spatial and temporal expression of the retinoic acid receptor in the regenerating amphibian limb. Nature 337 566569. (https://doi.org/10.1038/337566a0)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Lyn S, Yip P, Siu CH & Amin S 1990a Molecular cloning of a cDNA encoding a second cellular retinoic acid-binding protein. PNAS 87 62336237. (https://doi.org/10.1073/pnas.87.16.6233)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Shago M, Zirngibl R, Tate P, Rossant J & Varmuza S 1990b Identification of a novel isoform of the retinoic acid receptor g expressed in the mouse embryo. Molecular and Cellular Biology 10 23352340. (https://doi.org/10.1128/mcb.10.5.2335-2340.1990)

    • Search Google Scholar
    • Export Citation
  • Gilfix BM & Eckert RL 1985 Coordinate control by vitamin A of keratin gene expression in human keratinocytes. Journal of Biological Chemistry 260 1402614029. (https://doi.org/10.1016/S0021-9258(1738679-9)

    • Search Google Scholar
    • Export Citation
  • Gorman CM, Merlino GT, Willingham MC, Pastan I & Howard BH 1982 The Rous sarcoma virus long terminal repeat is a strong promoter when introduced into a variety of eukaryotic cells by DNA-mediated transfection. PNAS 79 67776781. (https://doi.org/10.1073/pnas.79.22.6777)

    • Search Google Scholar
    • Export Citation
  • Green S & Chambon P 1987 Oestradiol induction of a glucocorticoid-responsive gene by a chimaeric receptor. Nature 325 7578. (https://doi.org/10.1038/325075a0)

    • Search Google Scholar
    • Export Citation
  • Green S, Walter P, Kumar V, Krust A, Bornet JM, Argos P & Chambon P 1986 Human oestrogen receptor cDNA: sequence, expression and homology to v-erbA. Nature 320 134139. (https://doi.org/10.1038/320134a0)

    • Search Google Scholar
    • Export Citation
  • Greene GL, Gilna P, Waterfield M, Baker A, Hort Y & Shine J 1986 Sequence and expression of human estrogen receptor complementary DNA. Science 231 11501154. (https://doi.org/10.1126/science.3753802)

    • Search Google Scholar
    • Export Citation
  • Hamada K, Gleason SL, Levi BZ, Hirschfeld S, Appella E & Ozato K 1989 H-2RIIBP, a member of the nuclear hormone receptor superfamily that binds to both regulatory element of major histocompatibility class I genes and the estrogen response element. PNAS 86 82898293. (https://doi.org/10.1073/pnas.86.21.8289)

    • Search Google Scholar
    • Export Citation
  • Haussler M, Sidell N, Kelly M, Donaldson C, Altman A & Mangelsdorf D 1983 Specific highaffinity binding and biologic action of retinoic acid in human neuroblastoma cell lines. PNAS 80 55255529. (https://doi.org/10.1073/pnas.80.18.5525)

    • Search Google Scholar
    • Export Citation
  • Heyman RA, Mangelsdorf DJ, Dyck JA, Stein RB, Eichele G, Evans RM & Thaller C 1992 9-cis retinoic acid is a high affinity ligand for the retinoid X receptor. Cell 68 397406. (https://doi.org/10.1016/0092-8674(9290479-v)

    • Search Google Scholar
    • Export Citation
  • Hoffman B, Lehmann JM, Zhang XK, Hermann T, Husmann M, Graupner G & Pfahl M 1990 A retinoic acid receptor-specific element controls the retinoic acid receptor-b promoter. Molecular Endocrinology 4 17271736. (https://doi.org/10.1210/mend-4-11-1727)

    • Search Google Scholar
    • Export Citation
  • Hollenberg SM, Weinberger C, Ong ES, Cerelli G, Oro A, Lebo R, Thompson EB, Rosenfeld MG & Evans RM 1985 Primary structure and expression of a functional human glucocorticoid receptor cDNA. Nature 318 635641. (https://doi.org/10.1038/318635a0)

    • Search Google Scholar
    • Export Citation
  • Hopkins FG 1906 The analysis and the medical man. Analyst 31 385397. (https://doi.org/10.1039/an906310385b)

  • Hopkins FG 1912 Feeding experiments illustrating the importance of accessory factors in normal dietaries. Journal of Physiology 44 425460. (https://doi.org/10.1113/jphysiol.1912.sp001524)

    • Search Google Scholar
    • Export Citation
  • Huang ME, Ye YC, Chen SR, Chai JR, Lu JX, Zhoa L, Gu LJ & Wang ZY 1988 Use of alltrans retinoic acid in the treatment of acute promyelocytic leukemia. Blood 72 567572.

    • Search Google Scholar
    • Export Citation
  • Ito YL, Zile M, Ahrens H & DeLuca HF 1974 Liquid-gel partition chromatography of vitamin A compounds; formation of retinoic acid from retinyl acetate in vivo. Journal of Lipid Research 15 517524. (https://doi.org/10.1016/S0022-2275(2036772-9)

    • Search Google Scholar
    • Export Citation
  • Kakizuka A, Miller Jr WH, Umesono K, Warrell Jr RP, Frankel SR, Murty VVVS, Dimitrovsky E & Evans RM 1991 Chromosomal translocation t(15;17) in human acute promyelocytic leukemia fuses RARa with a novel putative transcription factor, PML. Cell 66 663674. (https://doi.org/10.1016/0092-8674(9190112-c)

    • Search Google Scholar
    • Export Citation
  • Kastner P, Krust A, Mendelsohn C, Garnier JM, Zelent A, Leroy P, Staub A & Chambon P 1990 Murine isoforms of retinoic acid receptor g with specific patterns of expression. PNAS 87 27002704. (https://doi.org/10.1073/pnas.87.7.2700)

    • Search Google Scholar
    • Export Citation
  • Kliewer SA, Umesono K, Mangelsdorf DJ & Evans RM 1992 Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling. Nature 355 446449. (https://doi.org/10.1038/355446a0)

    • Search Google Scholar
    • Export Citation
  • Kocher HM, Basu B, Froeling FEM, Sarker D, Slater S, Carlin D, deSouza NM, De Paepe KN, Goulart MR & Hughes C et al.2020 Phase I clinical trial repurposing all-trans retinoic acid as a stromal targeting agent for pancreatic cancer. Nature Communications 11 4841. (https://doi.org/10.1038/s41467-020-18636-w)

    • Search Google Scholar
    • Export Citation
  • Koikawa K, Kibe S, Suizu F, Sekino N, Kim N, Manz TD, Pinch BJ, Akshinthala D, Verma A & Gaglia G et al.2021 Targeting Pin1 renders pancreatic cancer eradicable by synergizing with immunochemotherapy. Cell 184 4753 .e274771.e27. (https://doi.org/10.1016/j.cell.2021.07.020)

    • Search Google Scholar
    • Export Citation
  • Krust A, Kastner P, Petkovich M, Zelent A & Chambon P 1989 A third human retinoic acid receptor, hRAR-gamma. PNAS 86 53105314. (https://doi.org/10.1073/pnas.86.14.5310)

    • Search Google Scholar
    • Export Citation
  • Kumar V, Green S, Stack G, Berry M, Jin JR & Chambon P 1987 Functional domains of the human estrogen receptor. Cell 51 941951. (https://doi.org/10.1016/0092-8674(8790581-2)

    • Search Google Scholar
    • Export Citation
  • Kurokawa R, Yu VC, Näär A, Kyakumoto S, Han Z, Silverman S, Rosenfeld MG & Glass CK 1993 Differential orientations of the DNA binding domain and C-terminal dimerization interface regulate binding site selection by nuclear receptor heterodimers. Genes and Development 7 14231435. (https://doi.org/10.1101/gad.7.7b.1423)

    • Search Google Scholar
    • Export Citation
  • Leid M, Kastner P, Lyons R, Nakshari H, Saunders M, Zacharewski T, Chen JY, Staub A, Garnier JM & Mader S 1992 Purification, cloning, and RXR identity of the HeLa cell factor with which RAR or TR heterodimerizes to bind target sequences efficiently. Cell 68 377395. (https://doi.org/10.1016/0092-8674(9290478-u)

    • Search Google Scholar
    • Export Citation
  • Leroy P, Krust A, Zelent A, Mendelsohn C, Garnier JM, Kastner P, Dierich A & Chambon P 1991 Multiple isoforms of the mouse retinoic acid receptor a are generated by alternative splicing and differential induction by retinoic acid. EMBO Journal 10 5969. (https://doi.org/10.1002/j.1460-2075.1991.tb07921.x)

    • Search Google Scholar
    • Export Citation
  • Levin AA, Sturzenbecker LJ, Kazmer S, Bosakowski T, Huselton C, Allenby G, Speck J, Kratzeisen C, Rosenberger M & Lovey A 1992 9-cis retinoic acid stereoisomer binds and activates the nuclear receptor RXRa. Nature 355 359361. (https://doi.org/10.1038/355359a0)

    • Search Google Scholar
    • Export Citation
  • Longo L, Pandolfi PP, Biondi A, Rambaldi A, Mencarelli A, Lo Coco F, Diverio D, Pegoraro L, Avanzi G & Tabilio A 1990 Rearrangements and aberrant expression of the retinoic acid receptor a gene in acute promyelocytic leukemias. Journal of Experimental Medicine 172 15711575. (https://doi.org/10.1084/jem.172.6.1571)

    • Search Google Scholar
    • Export Citation
  • Lotan R, Stolarsky T & Lotan D 1983 Isolation and analysis of melanoma cell mutants resistant to the antiproliferative action of retinoic acid. Cancer Research 43 28682875.

    • Search Google Scholar
    • Export Citation
  • Lunin N 1881 Über die bedeutung der anorganischen salze für die ernährung des thieres. Zeitschrift für Physiologische Chemie 5 3139.

  • Mangelsdorf DJ, Ong ES, Dyck JA & Evans RM 1990 Nuclear receptor that identifies a novel retinoic acid response pathway. Nature 345 224229. (https://doi.org/10.1038/345224a0)

    • Search Google Scholar
    • Export Citation
  • Mangelsdorf DJ, Borgmeyer U, Heyman RA, Zhou JY, Ong ES, Oro AE, Kakizuka A & Evans RM 1992 Characterization of three RXR genes that mediate the action of 9-cis retinoic acid. Genes and Development 6 329344. (https://doi.org/10.1101/gad.6.3.329)

    • Search Google Scholar
    • Export Citation
  • Marks MS, Hallenbeck PL, Nagata T, Segars JH, Appella E, Nikodem VM & Ozato K 1992 H2RIIBP (RXRβ) heterodimerization provides a mechanism for combinatorial diversity in the regulation of retinoic acid and thyroid hormone responsive genes. EMBO Journal 11 14191435. (https://doi.org/10.1002/j.1460-2075.1992.tb05187.x)

    • Search Google Scholar
    • Export Citation
  • McCollum EV, Simmonds N & Parsons HT 1918 A biological analysis of pellagra-producing diets. Journal of Biological Chemistry 33 411423. (https://doi.org/10.1016/S0021-9258(1886558-9)

    • Search Google Scholar
    • Export Citation
  • Mere Del Aguila E, Tang XH & Gudas LJ 2022 Pancreatic ductal adenocarcinoma: new insights into the actions of vitamin A. Oncology Research and Treatment 45 291298. (https://doi.org/10.1159/000522425)

    • Search Google Scholar
    • Export Citation
  • Miesfeld R, Godowski PJ, Maler BA & Yamamoto KR 1987 Glucocorticoid receptor mutants that define a small region sufficient for enhancer activation. Science 236 423427. (https://doi.org/10.1126/science.3563519)

    • Search Google Scholar
    • Export Citation
  • Mikkelsen S, Berne B, Staberg B & Vahlquist A 1998 Potentiating effect of dietary vitamin A on photocarcinogenesis in hairless mice. Carcinogenesis 19 663666. (https://doi.org/10.1093/carcin/19.4.663)

    • Search Google Scholar
    • Export Citation
  • Mollersen L, Paulsen JE, Olstorn HB, Knutsen HK & Alexander J 2004 Dietary retinoic acid supplementation stimulates intestinal tumour formation and growth in multiple intestinal neoplasia (Min)/+ mice. Carcinogenesis 25 149153. (https://doi.org/10.1093/carcin/bgg176)

    • Search Google Scholar
    • Export Citation
  • Näär AM, Boutin JM, Lipkin SM, Yu VC, Holloway JM, Glass CK & Rosenfeld MG 1991 The orientation and spacing of core DNA-binding motifs dictate selective transcriptional responses to three nuclear receptors. Cell 65 12671279. (https://doi.org/10.1016/0092-8674(9190021-p)

    • Search Google Scholar
    • Export Citation
  • Nagpal S, Zelent A & Chambon P 1992 RAR-β4, a retinoic acid receptor isoform is generated from RAR-β2 by alternative splicing and usage of a CUG initiator codon. PNAS 89 27182722. (https://doi.org/10.1073/pnas.89.7.2718)

    • Search Google Scholar
    • Export Citation
  • Omenn GS, Goodman GE, Thornquist MD, Balmes J, Cullen MR, Glass A, Keogh JP, Meyskens FL, Valanis B & Williams JH et al.1996 Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. New England Journal of Medicine 334 11501155. (https://doi.org/10.1056/NEJM199605023341802)

    • Search Google Scholar
    • Export Citation
  • Ong DE & Chytil F 1978 Cellular retinoic acid-binding protein from rat testis. Journal of Biological Chemistry 253 45514554. (https://doi.org/10.1016/S0021-9258(1730423-4)

    • Search Google Scholar
    • Export Citation
  • Payvar F, Wrange O, Carlstedt-Duke J, Okret S, Gustafsson JA & Yamamoto KR 1981 Purified glucocorticoid receptors bind selectively in vitro to a cloned DNA fragment whose transcription is regulated by glucocorticoids in vivo. PNAS 78 66286632. (https://doi.org/10.1073/pnas.78.11.6628)

    • Search Google Scholar
    • Export Citation
  • Perlmann T, Rangarajan PN, Umesono K & Evans RM 1993 Determinants for selective RAR and TR recognition of direct repeat HREs. Genes and Development 7 14111422. (https://doi.org/10.1101/gad.7.7b.1411)

    • Search Google Scholar
    • Export Citation
  • Petkovich M, Brand NJ, Krust A & Chambon P 1987 A human retinoic acid receptor which belongs to the family of nuclear receptors. Nature 330 444450. (https://doi.org/10.1038/330444a0)

    • Search Google Scholar
    • Export Citation
  • Picard D, Salser SJ & Yamamoto KR 1988 A movable and regulable inactivation function within the steroid binding domain of the glucocorticoid receptor. Cell 54 10731080. (https://doi.org/10.1016/0092-8674(8890122-5)

    • Search Google Scholar
    • Export Citation
  • Predki PF, Zamble D, Sarkar B & Giguère V 1994 Ordered binding of retinoic acid and retinoid X receptors to asymmetric response elements involves determinants adjacent to the DNA-binding domain. Molecular Endocrinology 8 3139. (https://doi.org/10.1210/mend.8.1.8152429)

    • Search Google Scholar
    • Export Citation
  • Ragsdale CW, Petkovich M, Gates PB, Chambon P & Brockes JP 1989 Identification of a novel retinoic acid receptor in regenerative tissues of the newt. Nature 341 654657. (https://doi.org/10.1038/341654a0)

    • Search Google Scholar
    • Export Citation
  • Ragsdale Jr CW, Gates PB & Brockes JP 1992 Identification and expression pattern of a second isoform of the newt alpha retinoic acid receptor. Nucleic Acids Research 20 5851. (https://doi.org/10.1093/nar/20.21.5851)

    • Search Google Scholar
    • Export Citation
  • Rossant J, Zirngibl R, Cado D, Shago M & Giguère V 1991 Expression of a retinoic acid response element-hsplacZ transgene defines specific domains of transcriptional activity during mouse embryogenesis. Genes and Development 5 13331344. (https://doi.org/10.1101/gad.5.8.1333)

    • Search Google Scholar
    • Export Citation
  • Ruhl R, Krzyzosiak A, Niewiadomska-Cimicka A, Rochel N, Szeles L, Vaz B, WietrzychSchindler M, Alvarez S, Szklenar M & Nagy L et al.2015 9-cis-13,14-dihydroretinoic acid is an endogenous retinoid acting as RXR ligand in mice. PLoS Genetics 11 e1005213. (https://doi.org/10.1371/journal.pgen.1005213)

    • Search Google Scholar
    • Export Citation
  • Sap J, Munoz A, Damm K, Goldberg Y, Ghysdael J, Leutz A, Beug H & Vennström B 1986 The c-erb-A protein is a high-affinity receptor for thyroid hormone. Nature 324 635640. (https://doi.org/10.1038/324635a0)

    • Search Google Scholar
    • Export Citation
  • Scholtes C & Giguère V 2022 Transcriptional control of energy metabolism by nuclear receptors. Nature Reviews: Molecular Cell Biology 24 [epub]. (https://doi.org/10.1038/s41580-022-00486-7)

    • Search Google Scholar
    • Export Citation
  • Schroder EW, Rapaport E, Kabcenell AK & Black PH 1982 Growth inhibitory and stimulatory effects of retinoic acid on murine 3T3 cells. PNAS 79 15491552. (https://doi.org/10.1073/pnas.79.5.1549)

    • Search Google Scholar
    • Export Citation
  • Semba RD 2012 On the ‘discovery’ of vitamin A. Annals of Nutrition and Metabolism 61 192198. (https://doi.org/10.1159/000343124)

  • Shubeita HE, Sambrook JF & McCormick AM 1987 Molecular cloning and analysis of functional cDNA and genomic clones encoding bovine cellular retinoic acid-binding protein. PNAS 84 56455649. (https://doi.org/10.1073/pnas.84.16.5645)

    • Search Google Scholar
    • Export Citation
  • Singletary SE, Atkinson EN, Hoque A, Sneige N, Sahin AA, Fritsche Jr HA, Lotan R, Lu T, Hittelman WN & Bevers TB et al.2002 Phase II clinical trial of N-(4-hydroxyphenyl)retinamide and tamoxifen administration before definitive surgery for breast neoplasia. Clinical Cancer Research 8 28352842.

    • Search Google Scholar
    • Export Citation
  • Smith SM & Eichele G 1991 Temporal and regional differences in the expression pattern of distinct retinoic acid receptor-b transcripts in the chick embryo. Development 111 245252. (https://doi.org/10.1242/dev.111.1.245)

    • Search Google Scholar
    • Export Citation
  • Sporn MB & Roberts AB 1983 Role of retinoids in differentiation and carcinogenesis. Cancer Research 43 30343040.

  • Stone JC, Atkinson T, Smith M & Pawson T 1984 Identification of functional regions in the transforming protein of Fujinami sarcoma virus by in-phase insertion mutagenesis. Cell 37 549558. (https://doi.org/10.1016/0092-8674(8490385-4)

    • Search Google Scholar
    • Export Citation
  • Strickland S & Mahdavi V 1978 The induction of differentiation in teratocarcinoma stem cells by retinoic acid. Cell 15 393403. (https://doi.org/10.1016/0092-8674(7890008-9)

    • Search Google Scholar
    • Export Citation
  • Sucov HM, Murakami KK & Evans RM 1990 Characterization of an autoregulated response element in the mouse retinoic acid receptor type b gene. PNAS 87 5392–5396. (https://doi.org/10.1073/pnas87.14.5392)

    • Search Google Scholar
    • Export Citation
  • Thompson CC, Weinberger C, Lebo R & Evans RM 1987 Identification of a novel thyroid hormone receptor expressed in the mammalian central nervous system. Science 237 16101614. (https://doi.org/10.1126/science.3629259)

    • Search Google Scholar
    • Export Citation
  • Umesono K, Murakami KK, Thompson CC & Evans RM 1991 Direct repeats as selective response elements for the thyroid hormone, retinoic acid, and vitamin D3 receptors. Cell 65 12551266. (https://doi.org/10.1016/0092-8674(9190020-y)

    • Search Google Scholar
    • Export Citation
  • Van Dorp DA & Arens JF 1946 Biological activity of vitamin A acid. Nature 158 60. (https://doi.org/10.1038/158060a0)

  • Wang SY, LaRosa GJ & Gudas LJ 1985 Molecular cloning of gene sequences transcriptionally regulated by retinoic acid and dibutyryl cyclic AMP in cultured mouse teratocarcinoma cells. Developmental Biology 107 7586. (https://doi.org/10.1016/0012-1606(8590377-x)

    • Search Google Scholar
    • Export Citation
  • Weinberger C, Hollenberger SM, Rosenfeld MG & Evans RM 1985 Domain structure of human glucocorticoid receptor and its relations to the v-erb-A oncogene product. Nature 318 670672. (https://doi.org/10.1038/318670a0)

    • Search Google Scholar
    • Export Citation
  • Weinberger C, Thompson CC, Ong ES, Lebo R, Gruol DJ & Evans RM 1986 The c-erb-A gene encodes a thyroid hormone receptor. Nature 324 641646. (https://doi.org/10.1038/324641a0)

    • Search Google Scholar
    • Export Citation
  • Wolbach SB & Howe PR 1925 Tissue changes following deprivation of fat soluble A vitamin. Journal of Experimental Medicine 42 753777. (https://doi.org/10.1084/jem.42.6.753)

    • Search Google Scholar
    • Export Citation
  • Yu VC, Delsert C, Andersen B, Holloway JM, Devary OV, Näär AM, Kim SY, Boutin JM, Glass CK & Rosenfeld MG 1991 RXRβ: a coregulator that enhances binding of retinoic acid, thyroid hormone, and vitamin D receptors to their cognate response elements. Cell 67 12511266. (https://doi.org/10.1016/0092-8674(9190301-e)

    • Search Google Scholar
    • Export Citation
  • Yu X, Yi P, Hamilton RA, Shen H, Chen M, Foulds CE, Mancini MA, Ludtke SJ, Wang Z & O’Malley BW 2020 Structural insights of transcriptionally active, full-length androgen receptor coactivator complexes. Molecular Cell 79 812 .e4823.e4. (https://doi.org/10.1016/j.molcel.2020.06.031)

    • Search Google Scholar
    • Export Citation
  • Zelent A, Krust A, Petkovich M, Kastner P & Chambon P 1989 Cloning of murine a and β retinoic acid receptors and a novel receptor G predominantly expressed in skin. Nature 339 714–717. (https://doi.org/1038/339714a0)

    • Search Google Scholar
    • Export Citation
  • Zelent A, Mendelsohn C, Kastner P, Garnier JM, Ruffenach F, Leroy P & Chambon P 1991 Differentially expressed isoforms of the mouse retinoic acid receptor b are generated by usage of two promoters and alternative splicing. EMBO Journal 10 7181. (https://doi.org/10.1002/j.1460-2075.1991.tb07992.x)

    • Search Google Scholar
    • Export Citation
  • Zhang XK, Hoffmann B, Tran PB-V, Graupner G & Pfahl M 1992 Retinoid X receptor is an auxiliary protein for thyroid hormone and retinoic acid receptors. Nature 355 441446. (https://doi.org/10.1038/355441a0)

    • Search Google Scholar
    • Export Citation

 

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    Figure 1

    Schematic representation of the strategy leading to the discovery of the retinoic receptor (RAR). Top: schematic representation of the construction of the hybrid receptor. The main functional domains of the receptors are indicated by DBD (DNA-binding) and LBD (ligand-binding). The LBDs also indicate the identity of the natural ligand of each parent receptor. The cDNAs encoding each receptor were mutated to introduce novel restriction enzyme sites (Not1 and Xho1) bordering the DBD. The mutations did not modify the amino acid sequence of each parent receptor. The DBD of the RAR was then switch for the DBD of the glucocorticoid receptor (GR), generating a hybrid receptor (RGR) now able to recognize the glucocorticoid response element (GRE) located within the mouse mammary tumor virus (MMTV) long terminal repeat (LTR). The reporter plasmid consisted in the MMTV-LTR driving the expression of the bacterial gene encoding the enzyme chloramphenicol acetyl transferase (CAT). The hybrid RGR construct as well as the two parent receptors (GR and RAR as positive and negative controls, respectively) were then independently co-transfected into CV-1 cells together with the MMTV-CAT reporter plasmid. Bottom: schematic representation of the result of the original CAT assay performed with extracts obtained from co-transfected cells challenged with a series of putative ligands. The assay revealed in a singular eureka moment that at-RA (RA) was the only ligand eliciting a powerful increase in CAT activity in the presence of the hybrid receptor RGR. A receptor for at-RA had been discovered. A, aldosterone; AC, acetyl chloramphenicol; C, chloramphenicol; OHC, 25-hydroxy-cholesterol; D, dihydrotestosterone; DEX, dexamethasone; E2, estradiol; P, progesterone; RA, all-trans-retinoic acid; T3, triiodothyronine; T4, thyroxine; VD3, vitamin D3.

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    Figure 2

    The authors a few months after the discovery of the RAR. Left, Vincent Giguère; right, Ronald M Evans. August 1988, La Jolla, California.

  • Albright CD, Salganik RI & Van Dyke T 2004 Dietary depletion of vitamin E and vitamin A inhibits mammary tumor growth and metastasis in transgenic mice. Journal of Nutrition 134 11391144. (https://doi.org/10.1093/jn/134.5.1139)

    • Search Google Scholar
    • Export Citation
  • Alcalay M, Zangrilli D, Pandolfi PP, Longo L, Mencarelli A, Giacomicci A, Rocchi M, Biondi A, Rambaldi A & Coco FL 1991 Translocation breakpoint of acute promyelocytic leukemia lies within the retinoic acid receptor a locus. PNAS 88 19771981. (https://doi.org/10.1073/pnas.88.5.1977)

    • Search Google Scholar
    • Export Citation
  • Arens JF & Van Dorp DA 1946a Synthesis of some compounds possessing vitamin A activity. Nature 157 190. (https://doi.org/10.1038/157190a0)

  • Arens JF & Van Dorp DA 1946b Activity of vitamin A-acid in the rat. Nature 158 622. (https://doi.org/10.1038/158622c0)

  • Arriza JL, Weinberger C, Cerelli G, Glaser TM, Handelin BL, Housman DE & Evans RM 1987 Cloning of human mineraloccorticoid receptor complementary DNA: structural and functional kinship with the glucocorticoid receptor. Science 237 268275. (https://doi.org/10.1126/science.3037703)

    • Search Google Scholar
    • Export Citation
  • Borrow J, Goddard AD, Sheer D & Solomon E 1990 Molecular analysis of acute promyelocytic leukemia breakpoint cluster region on chromosome 17. Science 249 15771580. (https://doi.org/10.1126/science.2218500)

    • Search Google Scholar
    • Export Citation
  • Brand N, Petkovich M, Krust A, Chambon P, de Thé H, Marchio A, Tiollais P & Dejean A 1988 Identification of a second human retinoic acid receptor. Nature 332 850853. (https://doi.org/10.1038/332850a0)

    • Search Google Scholar
    • Export Citation
  • Breitman TR, Selonick SE & Collins SJ 1980 Induction of differentiation of the human promyelocytic leukemia cell line (HL-60) by retinoic acid. PNAS 77 29362940. (https://doi.org/10.1073/pnas.77.5.2936)

    • Search Google Scholar
    • Export Citation
  • Bugge TH, Pohl J, Lonnoy O & Stunnenberg HG 1992 RXRa, a promiscuous partner of retinoic acid and thyroid hormone receptors. EMBO Journal 11 14091418. (https://doi.org/10.1002/j.1460-2075.1992.tb05186.x)

    • Search Google Scholar
    • Export Citation
  • Castaigne S, Chomienne C, Daniel MT, Ballerini P, Berger R, Fenaux P & Degos L 1990 All-trans retinoic acid as a differentiation therapy for acute promyelocytic leukemia. I. Clinical results. Blood 76 17041709.

    • Search Google Scholar
    • Export Citation
  • Chandler VL, Maler BA & Yamamoto KR 1983 DNA sequences bound specifically by glucocorticoid receptor in vitro render a heterologous promoter hormone responsive in vivo. Cell 33 489499. (https://doi.org/10.1016/0092-8674(8390430-0)

    • Search Google Scholar
    • Export Citation
  • Chandra V, Huang P, Hamuro Y, Raghuram S, Wang Y, Burris TP & Rastinejad F 2008 Structure of the intact PPAR-γ-RXR-α nuclear receptor complex on DNA. Nature 456 350356. (https://doi.org/10.1038/nature07413)

    • Search Google Scholar
    • Export Citation
  • Chandra V, Huang P, Potluri N, Wu D, Kim Y & Rastinejad F 2013 Multidomain integration in the structure of the HNF-4α nuclear receptor complex. Nature 495 394398. (https://doi.org/10.1038/nature11966)

    • Search Google Scholar
    • Export Citation
  • Chiesa MD, Passalacqua R, Michiara M, Franciosi V, Di Costanzo F, Bisagni G, Camisa R, Buti S, Tomasello G & Cocconi G et al.2007 Tamoxifen vs tamoxifen plus 13-cis-retinoic acid vs tamoxifen plus interferon alpha-2a as first-line endocrine treatments in advanced breast cancer: updated results of a phase II, prospective, randomised multicentre trial. Acta Biomedica 78 204209.

    • Search Google Scholar
    • Export Citation
  • Chytil F 1986 Retinoic acid: biochemistry and metabolism. Journal of the American Academy of Dermatology 15 741747. (https://doi.org/10.1016/s0190-9622(8670229-6)

    • Search Google Scholar
    • Export Citation
  • Chytil F & Ong DE 1979 Cellular retinol- and retinoic acid-binding proteins in vitamin A action. Federation Proceedings 38 25102514.

  • de Thé H, Chomienne C, Lanotte M, Degos L & Dejean A 1990a The t(15;17) translocation of acute promyelocytic leukemia fuses the retinoic acid receptor a gene to a novel transcribed locus. Nature 347 558561. (https://doi.org/10.1038/347558a0)

    • Search Google Scholar
    • Export Citation
  • de Thé H, del Mar Vivanco-Ruiz M, Tiollais P, Stunneberg H & Dejean A 1990b Identification of a retinoic acid responsive element in the retinoic acid receptor β gene. Nature 343 177180. (https://doi.org/10.1038/343177a0)

    • Search Google Scholar
    • Export Citation
  • de Thé H, Lavau C, Marchio A, Chomienne C, Degos L & Dejean A 1991 The PML-RARa fusion mRNA generated by the t(15;17) translocation in acute promyelocytic leukemia encodes a functionally altered RAR. Cell 66 675684. (https://doi.org/10.1016/0092-8674(9190113-d)

    • Search Google Scholar
    • Export Citation
  • Degos L, Chomienne C, Daniel MT, Berger R, Dombret H, Fenaux P & Castaigne S 1990 Treatment of first relapse in acute promyelocytic leukaemia with all-trans retinoic acid. Lancet 336 14401441. (https://doi.org/10.1016/0140-6736(9093135-c)

    • Search Google Scholar
    • Export Citation
  • Dejean A, Bougueleret L, Grzeschik KH & Tiollais P 1986 Hepatitis B virus DNA integration in a sequence homologous to v-erb-A and steroid receptor genes in a hepatocellular carcinoma. Nature 322 7072. (https://doi.org/10.1038/322070a0)

    • Search Google Scholar
    • Export Citation
  • Dragnev KH, Petty WJ, Shah SJ, Lewis LD, Black CC, Memoli V, Nugent WC, Hermann T, Negro-Vilar A & Rigas JR et al.2007 A proof-of-principle clinical trial of bexarotene in patients with non-small cell lung cancer. Clinical Cancer Research 13 17941800. (https://doi.org/10.1158/1078-0432.CCR-06-1836)

    • Search Google Scholar
    • Export Citation
  • Drummond JC 1920 The nomenclature of the so-called accessory food factors (vitamins). Biochemical Journal 14 660. (https://doi.org/10.1042/bj0140660)

    • Search Google Scholar
    • Export Citation
  • Eckert RL & Green H 1984 Cloning of cDNAs specifying vitamin A-responsive human keratins. PNAS 81 43214325. (https://doi.org/10.1073/pnas.81.14.4321)

    • Search Google Scholar
    • Export Citation
  • Eilers M, Picard D, Yamamoto KR & Bishop JM 1989 Chimeras of Myc oncoprotein and steroid receptors cause hormone-dependent transformation of cells. Nature 340 6668. (https://doi.org/10.1038/340066a0)

    • Search Google Scholar
    • Export Citation
  • Ellinger-Ziegelbauer H & Dreyer C 1991 A retinoic acid receptor expressed in the early development of Xenopus laevis. Genes and Development 5 94104. (https://doi.org/10.1101/gad.5.1.94)

    • Search Google Scholar
    • Export Citation
  • Emerick RJ, Zile M & DeLuca HF 1967 Formation of retinoic acid from retinol in the rat. Biochemical Journal 102 606611. (https://doi.org/10.1042/bj1020606)

    • Search Google Scholar
    • Export Citation
  • Esteva FJ, Glaspy J, Baidas S, Laufman L, Hutchins L, Dickler M, Tripathy D, Cohen R, DeMichele A & Yocum RC et al.2003 Multicenter phase II study of oral bexarotene for patients with metastatic breast cancer. Journal of Clinical Oncology 21 9991006. (https://doi.org/10.1200/JCO.2003.05.068)

    • Search Google Scholar
    • Export Citation
  • Evans RM 1988 The steroid and thyroid hormone receptor superfamily. Science 240 889895. (https://doi.org/10.1126/science.3283939)

  • Evans RM & Mangelsdorf DJ 2014 Nuclear receptors, RXR, and the big bang. Cell 157 255266. (https://doi.org/10.1016/j.cell.2014.03.012)

  • Fleischhauer K, Park JH, DiSanto JP, Marks M, Ozato K & Yang SY 1992 Isolation of a fulllength cDNA clone encoding a N-terminally variant form of the human retinoid X receptor β. Nucleic Acids Research 20 1801. (https://doi.org/10.1093/nar/20.7.1801)

    • Search Google Scholar
    • Export Citation
  • Giguère V 1994 Retinoic acid receptors and cellular retinoid binding proteins: complex interplay in retinoid signaling. Endocrine Reviews 15 6179. (https://doi.org/10.1210/edrv-15-1-61)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Isobe K & Grosveld F 1985 Structure of the murine Thy-1 gene. EMBO Journal 4 20172024. (https://doi.org/10.1002/j.1460-2075.1985.tb03886.x)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Hollenberg SM, Rosenfeld MG & Evans RM 1986 Functional domains of the human glucocorticoid receptor. Cell 46 645652. (https://doi.org/10.1016/0092-8674(8690339-9)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Ong ES, Segui P & Evans RM 1987 Identification of a receptor for the morphogen retinoic acid. Nature 330 624629. (https://doi.org/10.1038/330624a0)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Yang N, Segui P & Evans RM 1988 Identification of a new class of steroid hormone receptors. Nature 331 9194. (https://doi.org/10.1038/331091a0)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Ong ES, Evans RM & Tabin CJ 1989 Spatial and temporal expression of the retinoic acid receptor in the regenerating amphibian limb. Nature 337 566569. (https://doi.org/10.1038/337566a0)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Lyn S, Yip P, Siu CH & Amin S 1990a Molecular cloning of a cDNA encoding a second cellular retinoic acid-binding protein. PNAS 87 62336237. (https://doi.org/10.1073/pnas.87.16.6233)

    • Search Google Scholar
    • Export Citation
  • Giguère V, Shago M, Zirngibl R, Tate P, Rossant J & Varmuza S 1990b Identification of a novel isoform of the retinoic acid receptor g expressed in the mouse embryo. Molecular and Cellular Biology 10 23352340. (https://doi.org/10.1128/mcb.10.5.2335-2340.1990)

    • Search Google Scholar
    • Export Citation
  • Gilfix BM & Eckert RL 1985 Coordinate control by vitamin A of keratin gene expression in human keratinocytes. Journal of Biological Chemistry 260 1402614029. (https://doi.org/10.1016/S0021-9258(1738679-9)

    • Search Google Scholar
    • Export Citation
  • Gorman CM, Merlino GT, Willingham MC, Pastan I & Howard BH 1982 The Rous sarcoma virus long terminal repeat is a strong promoter when introduced into a variety of eukaryotic cells by DNA-mediated transfection. PNAS 79 67776781. (https://doi.org/10.1073/pnas.79.22.6777)

    • Search Google Scholar
    • Export Citation
  • Green S & Chambon P 1987 Oestradiol induction of a glucocorticoid-responsive gene by a chimaeric receptor. Nature 325 7578. (https://doi.org/10.1038/325075a0)

    • Search Google Scholar
    • Export Citation
  • Green S, Walter P, Kumar V, Krust A, Bornet JM, Argos P & Chambon P 1986 Human oestrogen receptor cDNA: sequence, expression and homology to v-erbA. Nature 320 134139. (https://doi.org/10.1038/320134a0)

    • Search Google Scholar
    • Export Citation
  • Greene GL, Gilna P, Waterfield M, Baker A, Hort Y & Shine J 1986 Sequence and expression of human estrogen receptor complementary DNA. Science 231 11501154. (https://doi.org/10.1126/science.3753802)

    • Search Google Scholar
    • Export Citation
  • Hamada K, Gleason SL, Levi BZ, Hirschfeld S, Appella E & Ozato K 1989 H-2RIIBP, a member of the nuclear hormone receptor superfamily that binds to both regulatory element of major histocompatibility class I genes and the estrogen response element. PNAS 86 82898293. (https://doi.org/10.1073/pnas.86.21.8289)

    • Search Google Scholar
    • Export Citation
  • Haussler M, Sidell N, Kelly M, Donaldson C, Altman A & Mangelsdorf D 1983 Specific highaffinity binding and biologic action of retinoic acid in human neuroblastoma cell lines. PNAS 80 55255529. (https://doi.org/10.1073/pnas.80.18.5525)

    • Search Google Scholar
    • Export Citation
  • Heyman RA, Mangelsdorf DJ, Dyck JA, Stein RB, Eichele G, Evans RM & Thaller C 1992 9-cis retinoic acid is a high affinity ligand for the retinoid X receptor. Cell 68 397406. (https://doi.org/10.1016/0092-8674(9290479-v)

    • Search Google Scholar
    • Export Citation
  • Hoffman B, Lehmann JM, Zhang XK, Hermann T, Husmann M, Graupner G & Pfahl M 1990 A retinoic acid receptor-specific element controls the retinoic acid receptor-b promoter. Molecular Endocrinology 4 17271736. (https://doi.org/10.1210/mend-4-11-1727)

    • Search Google Scholar
    • Export Citation
  • Hollenberg SM, Weinberger C, Ong ES, Cerelli G, Oro A, Lebo R, Thompson EB, Rosenfeld MG & Evans RM 1985 Primary structure and expression of a functional human glucocorticoid receptor cDNA. Nature 318 635641. (https://doi.org/10.1038/318635a0)

    • Search Google Scholar
    • Export Citation
  • Hopkins FG 1906 The analysis and the medical man. Analyst 31 385397. (https://doi.org/10.1039/an906310385b)

  • Hopkins FG 1912 Feeding experiments illustrating the importance of accessory factors in normal dietaries. Journal of Physiology 44 425460. (https://doi.org/10.1113/jphysiol.1912.sp001524)

    • Search Google Scholar
    • Export Citation
  • Huang ME, Ye YC, Chen SR, Chai JR, Lu JX, Zhoa L, Gu LJ & Wang ZY 1988 Use of alltrans retinoic acid in the treatment of acute promyelocytic leukemia. Blood 72 567572.

    • Search Google Scholar
    • Export Citation
  • Ito YL, Zile M, Ahrens H & DeLuca HF 1974 Liquid-gel partition chromatography of vitamin A compounds; formation of retinoic acid from retinyl acetate in vivo. Journal of Lipid Research 15 517524. (https://doi.org/10.1016/S0022-2275(2036772-9)

    • Search Google Scholar
    • Export Citation
  • Kakizuka A, Miller Jr WH, Umesono K, Warrell Jr RP, Frankel SR, Murty VVVS, Dimitrovsky E & Evans RM 1991 Chromosomal translocation t(15;17) in human acute promyelocytic leukemia fuses RARa with a novel putative transcription factor, PML. Cell 66 663674. (https://doi.org/10.1016/0092-8674(9190112-c)

    • Search Google Scholar
    • Export Citation
  • Kastner P, Krust A, Mendelsohn C, Garnier JM, Zelent A, Leroy P, Staub A & Chambon P 1990 Murine isoforms of retinoic acid receptor g with specific patterns of expression. PNAS 87 27002704. (https://doi.org/10.1073/pnas.87.7.2700)

    • Search Google Scholar
    • Export Citation
  • Kliewer SA, Umesono K, Mangelsdorf DJ & Evans RM 1992 Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling. Nature 355 446449. (https://doi.org/10.1038/355446a0)

    • Search Google Scholar
    • Export Citation
  • Kocher HM, Basu B, Froeling FEM, Sarker D, Slater S, Carlin D, deSouza NM, De Paepe KN, Goulart MR & Hughes C et al.2020 Phase I clinical trial repurposing all-trans retinoic acid as a stromal targeting agent for pancreatic cancer. Nature Communications 11 4841. (https://doi.org/10.1038/s41467-020-18636-w)

    • Search Google Scholar
    • Export Citation
  • Koikawa K, Kibe S, Suizu F, Sekino N, Kim N, Manz TD, Pinch BJ, Akshinthala D, Verma A & Gaglia G et al.2021 Targeting Pin1 renders pancreatic cancer eradicable by synergizing with immunochemotherapy. Cell 184 4753 .e274771.e27. (https://doi.org/10.1016/j.cell.2021.07.020)

    • Search Google Scholar
    • Export Citation
  • Krust A, Kastner P, Petkovich M, Zelent A & Chambon P 1989 A third human retinoic acid receptor, hRAR-gamma. PNAS 86 53105314. (https://doi.org/10.1073/pnas.86.14.5310)

    • Search Google Scholar
    • Export Citation
  • Kumar V, Green S, Stack G, Berry M, Jin JR & Chambon P 1987 Functional domains of the human estrogen receptor. Cell 51 941951. (https://doi.org/10.1016/0092-8674(8790581-2)

    • Search Google Scholar
    • Export Citation
  • Kurokawa R, Yu VC, Näär A, Kyakumoto S, Han Z, Silverman S, Rosenfeld MG & Glass CK 1993 Differential orientations of the DNA binding domain and C-terminal dimerization interface regulate binding site selection by nuclear receptor heterodimers. Genes and Development 7 14231435. (https://doi.org/10.1101/gad.7.7b.1423)

    • Search Google Scholar
    • Export Citation
  • Leid M, Kastner P, Lyons R, Nakshari H, Saunders M, Zacharewski T, Chen JY, Staub A, Garnier JM & Mader S 1992 Purification, cloning, and RXR identity of the HeLa cell factor with which RAR or TR heterodimerizes to bind target sequences efficiently. Cell 68 377395. (https://doi.org/10.1016/0092-8674(9290478-u)

    • Search Google Scholar
    • Export Citation
  • Leroy P, Krust A, Zelent A, Mendelsohn C, Garnier JM, Kastner P, Dierich A & Chambon P 1991 Multiple isoforms of the mouse retinoic acid receptor a are generated by alternative splicing and differential induction by retinoic acid. EMBO Journal 10 5969. (https://doi.org/10.1002/j.1460-2075.1991.tb07921.x)

    • Search Google Scholar
    • Export Citation
  • Levin AA, Sturzenbecker LJ, Kazmer S, Bosakowski T, Huselton C, Allenby G, Speck J, Kratzeisen C, Rosenberger M & Lovey A 1992 9-cis retinoic acid stereoisomer binds and activates the nuclear receptor RXRa. Nature 355 359361. (https://doi.org/10.1038/355359a0)

    • Search Google Scholar
    • Export Citation
  • Longo L, Pandolfi PP, Biondi A, Rambaldi A, Mencarelli A, Lo Coco F, Diverio D, Pegoraro L, Avanzi G & Tabilio A 1990 Rearrangements and aberrant expression of the retinoic acid receptor a gene in acute promyelocytic leukemias. Journal of Experimental Medicine 172 15711575. (https://doi.org/10.1084/jem.172.6.1571)

    • Search Google Scholar
    • Export Citation
  • Lotan R, Stolarsky T & Lotan D 1983 Isolation and analysis of melanoma cell mutants resistant to the antiproliferative action of retinoic acid. Cancer Research 43 28682875.

    • Search Google Scholar
    • Export Citation
  • Lunin N 1881 Über die bedeutung der anorganischen salze für die ernährung des thieres. Zeitschrift für Physiologische Chemie 5 3139.

  • Mangelsdorf DJ, Ong ES, Dyck JA & Evans RM 1990 Nuclear receptor that identifies a novel retinoic acid response pathway. Nature 345 224229. (https://doi.org/10.1038/345224a0)

    • Search Google Scholar
    • Export Citation
  • Mangelsdorf DJ, Borgmeyer U, Heyman RA, Zhou JY, Ong ES, Oro AE, Kakizuka A & Evans RM 1992 Characterization of three RXR genes that mediate the action of 9-cis retinoic acid. Genes and Development 6 329344. (https://doi.org/10.1101/gad.6.3.329)

    • Search Google Scholar
    • Export Citation
  • Marks MS, Hallenbeck PL, Nagata T, Segars JH, Appella E, Nikodem VM & Ozato K 1992 H2RIIBP (RXRβ) heterodimerization provides a mechanism for combinatorial diversity in the regulation of retinoic acid and thyroid hormone responsive genes. EMBO Journal 11 14191435. (https://doi.org/10.1002/j.1460-2075.1992.tb05187.x)

    • Search Google Scholar
    • Export Citation
  • McCollum EV, Simmonds N & Parsons HT 1918 A biological analysis of pellagra-producing diets. Journal of Biological Chemistry 33 411423. (https://doi.org/10.1016/S0021-9258(1886558-9)

    • Search Google Scholar
    • Export Citation
  • Mere Del Aguila E, Tang XH & Gudas LJ 2022 Pancreatic ductal adenocarcinoma: new insights into the actions of vitamin A. Oncology Research and Treatment 45 291298. (https://doi.org/10.1159/000522425)

    • Search Google Scholar
    • Export Citation
  • Miesfeld R, Godowski PJ, Maler BA & Yamamoto KR 1987 Glucocorticoid receptor mutants that define a small region sufficient for enhancer activation. Science 236 423427. (https://doi.org/10.1126/science.3563519)

    • Search Google Scholar
    • Export Citation
  • Mikkelsen S, Berne B, Staberg B & Vahlquist A 1998 Potentiating effect of dietary vitamin A on photocarcinogenesis in hairless mice. Carcinogenesis 19 663666. (https://doi.org/10.1093/carcin/19.4.663)

    • Search Google Scholar
    • Export Citation
  • Mollersen L, Paulsen JE, Olstorn HB, Knutsen HK & Alexander J 2004 Dietary retinoic acid supplementation stimulates intestinal tumour formation and growth in multiple intestinal neoplasia (Min)/+ mice. Carcinogenesis 25 149153. (https://doi.org/10.1093/carcin/bgg176)

    • Search Google Scholar
    • Export Citation
  • Näär AM, Boutin JM, Lipkin SM, Yu VC, Holloway JM, Glass CK & Rosenfeld MG 1991 The orientation and spacing of core DNA-binding motifs dictate selective transcriptional responses to three nuclear receptors. Cell 65 12671279. (https://doi.org/10.1016/0092-8674(9190021-p)

    • Search Google Scholar
    • Export Citation
  • Nagpal S, Zelent A & Chambon P 1992 RAR-β4, a retinoic acid receptor isoform is generated from RAR-β2 by alternative splicing and usage of a CUG initiator codon. PNAS 89 27182722. (https://doi.org/10.1073/pnas.89.7.2718)

    • Search Google Scholar
    • Export Citation