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Bergeron F, Boulende Sab A, Bouchard MF, Taniguchi H, Souchkova O, Brousseau C, Tremblay JJ, Pilon N, Viger RS. Phosphorylation of GATA4 serine 105 but not serine 261 is required for testosterone production in the male mouse. Andrology 2019; 7:357-372. [PMID: 30793514 DOI: 10.1111/andr.12601] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND GATA4 is a transcription factor essential for male sex determination, testicular differentiation during fetal development, and male fertility in the adult. GATA4 exerts part of its function by regulating multiple genes in the steroidogenic enzyme pathway. In spite of these crucial roles, how the activity of this factor is regulated remains unclear. OBJECTIVES Studies in gonadal cell lines have shown that GATA4 is phosphorylated on at least two serine residues-serine 105 (S105) and serine 261 (S261)-and that this phosphorylation is important for GATA4 activity. The objective of the present study is to characterize the endogenous role of GATA4 S105 and S261 phosphorylation in the mouse testis. MATERIALS AND METHODS We examined both previously described GATA4 S105A mice and a novel GATA4 S261A knock-in mouse that we generated by CRISPR/Cas9 gene editing. The male phenotype of the mutants was characterized by assessing androgen-dependent organ weights, hormonal profiles, and expression of multiple testicular target genes using standard biochemical and molecular biology techniques. RESULTS The fecundity of crosses between GATA4 S105A mice was reduced but without a change in sex ratio. The weight of androgen-dependent organs was smaller when compared to wild-type controls. Plasma testosterone levels showed a 70% decrease in adult GATA4 S105A males. This decrease was associated with a reduction in Cyp11a1, Cyp17a1, and Hsd17b3 expression. GATA4 S261A mice were viable and testis morphology appeared normal. Testosterone production and steroidogenic enzyme expression were not altered in GATA4 S261A males. DISCUSSION AND CONCLUSION Our analysis showed that blocking GATA4 S105 phosphorylation is associated with decreased androgen production in males. In contrast, S261 phosphorylation by itself is dispensable for GATA4 function. These results confirm that endogenous GATA4 action is essential for normal steroid production in males and that this activity requires phosphorylation on at least one serine residue.
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Affiliation(s)
- F Bergeron
- Reproduction, Mother and Child Health, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada.,Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle (CRDSI), Quebec, QC, Canada
| | - A Boulende Sab
- Département des Sciences Biologiques and Centre d'excellence en Recherche sur les Maladies Orphelines - Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montreal, QC, Canada
| | - M F Bouchard
- Reproduction, Mother and Child Health, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada.,Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle (CRDSI), Quebec, QC, Canada
| | - H Taniguchi
- Institute of Genetics and Animal Breeding of the Polish Academy of Sciences, Jastrzebiec, Poland
| | - O Souchkova
- Département des Sciences Biologiques and Centre d'excellence en Recherche sur les Maladies Orphelines - Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montreal, QC, Canada
| | - C Brousseau
- Reproduction, Mother and Child Health, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada.,Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle (CRDSI), Quebec, QC, Canada
| | - J J Tremblay
- Reproduction, Mother and Child Health, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada.,Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle (CRDSI), Quebec, QC, Canada.,Department of Obstetrics, Gynecology, and Reproduction, Université Laval, Quebec, QC, Canada
| | - N Pilon
- Département des Sciences Biologiques and Centre d'excellence en Recherche sur les Maladies Orphelines - Fondation Courtois (CERMO-FC), Université du Québec à Montréal (UQAM), Montreal, QC, Canada
| | - R S Viger
- Reproduction, Mother and Child Health, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada.,Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle (CRDSI), Quebec, QC, Canada.,Department of Obstetrics, Gynecology, and Reproduction, Université Laval, Quebec, QC, Canada
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Di-Luoffo M, Brousseau C, Tremblay JJ. MEF2 and NR2F2 cooperate to regulate Akr1c14
gene expression in mouse MA-10 Leydig cells. Andrology 2016; 4:335-44. [DOI: 10.1111/andr.12150] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 11/03/2015] [Accepted: 11/19/2015] [Indexed: 01/04/2023]
Affiliation(s)
- M. Di-Luoffo
- Reproduction, Mother and Child Health; Centre de recherche du centre hospitalier universitaire de Québec; Québec City QC Canada
| | - C. Brousseau
- Reproduction, Mother and Child Health; Centre de recherche du centre hospitalier universitaire de Québec; Québec City QC Canada
| | - J. J. Tremblay
- Reproduction, Mother and Child Health; Centre de recherche du centre hospitalier universitaire de Québec; Québec City QC Canada
- Centre de recherche en biologie de la reproduction; Department of Obstetrics, Gynecology and Reproduction; Faculty of Medicine; Université Laval; Québec City QC Canada
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Lysiak JJ, Kirby JL, Tremblay JJ, Woodson RI, Reardon MA, Palmer LA, Turner TT. Hypoxia-Inducible Factor-1 Is Constitutively Expressed in Murine Leydig Cells and Regulates 3 -Hydroxysteroid Dehydrogenase Type 1 Promoter Activity. ACTA ACUST UNITED AC 2008; 30:146-56. [DOI: 10.2164/jandrol.108.006155] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Tremblay JJ. Modulation of Endogenous GATA-4 Activity Reveals Its Dual Contribution to Mullerian Inhibiting Substance Gene Transcription in Sertoli Cells. Mol Endocrinol 2001. [DOI: 10.1210/me.15.9.1636] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Tremblay JJ, Robert NM, Viger RS. Modulation of endogenous GATA-4 activity reveals its dual contribution to Müllerian inhibiting substance gene transcription in Sertoli cells. Mol Endocrinol 2001; 15:1636-50. [PMID: 11518812 DOI: 10.1210/mend.15.9.0692] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Secretion of Müllerian inhibiting substance by fetal Sertoli cells is essential for normal male sex differentiation since it induces regression of the Müllerian ducts in the developing male embryo. Proper spatiotemporal expression of the MIS gene requires a specific combination of transcription factors, including the zinc finger factor GATA-4 and the nuclear receptor steroidogenic factor-1, which both colocalize with Müllerian inhibiting substance in Sertoli cells. To establish the molecular mechanisms through which GATA-4 contributes to MIS transcription, we have generated and characterized novel GATA-4 dominant negative competitors. The first one, which consisted solely of the GATA-4 zinc finger DNA-binding domain, was an efficient competitor of GATA transcription mediated both by direct GATA binding to DNA and protein-protein interactions involving GATA factors. The second type of competitor consisted of the same GATA-4 zinc finger DNA-binding domain but harboring mutations that prevented DNA binding. This second class of competitors repressed GATA-dependent transactivation by specifically competing for GATA protein-protein interactions without affecting the DNA-binding activity of endogenous GATA factors. These competitors, along with the GATA-4 cofactor FOG-2 (friend of GATA-2), were used to specifically modulate endogenous GATA-4 activity in Sertoli cells. Our results indicate that GATA-4 contributes to MIS promoter activity through two distinct mechanisms. Moreover, the GATA competitors described here should provide invaluable in vitro and in vivo tools for the study of GATA- dependent transcription and the identification of new target genes.
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Affiliation(s)
- J J Tremblay
- Ontogeny and Reproduction Research Unit, Centre Hospitalier de l'Université Laval Research Centre, Ste-Foy, Quebec, Canada
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7
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Abstract
A crucial step in mammalian sex differentiation is the regression of the Müllerian ducts in males. This is achieved through the action of Müllerian inhibiting substance (MIS), a key hormone produced by fetal Sertoli cells. Proper spatiotemporal expression of the MIS gene requires the concerted action of several transcription factors that include Sox9, SF-1, WT-1, GATA-4, and Dax-1. Indeed, SF-1 contributes to MIS gene expression by transcriptionally cooperating with other factors such as GATA-4 and WT-1. Dax-1 is coexpressed with SF-1 in many tissues, including the gonads, where it acts as a negative modulator of SF-1-dependent transcription. We now report that Dax-1 can repress MIS transcription in Sertoli cells by disrupting transcriptional synergism between GATA-4 and SF-1. Dax-1-mediated repression of GATA-4/SF-1 synergism did not involve direct repression of GATA-dependent transactivation, but rather, it occurred through a direct protein-protein interaction with DNA-bound SF-1. It is interesting that SF-1, Dax-1, and GATA factors are coexpressed in several tissues such as the pituitary, the adrenals, and the gonads. Because we have shown that other GATA family members also have the ability to synergize with SF-1, Dax-1 repression of GATA/SF-1 synergism may represent an important mechanism for fine-tuning the regulation of SF-1-dependent genes in multiple target tissues.
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Affiliation(s)
- J J Tremblay
- Ontogeny and Reproduction Research Unit, CHUL Research Centre and Centre for Research in Biology of Reproduction, Department of Obstetrics and Gynecology, Laval University, Ste-Foy, Québec, Canada G1V 4G2
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Abstract
The GATA factors are a group of transcriptional regulators that play essential roles in cell differentiation, organ morphogenesis, and tissue-specific gene expression during development. The six vertebrate GATA factors are expressed in a broad spectrum of tissues, including the hemopoietic system, heart, gut, brain, placenta, pituitary, and gonads. Interestingly, GATA-like DNA-binding proteins are found in the gonads of several species, ranging from lower invertebrates to humans, thus supporting an evolutionary conserved and crucial role for these factors in gonadal development and function. Indeed, GATA factors are expressed from the onset of gonadal development and are later found in multiple cell lineages of both the testis and ovary. We now report that GATA-4 differentially activates transcription of several genes expressed in the gonads that encode either steroidogenic enzymes (steroidogenic acute regulatory protein and aromatase), hormones (inhibin alpha and Müllerian inhibiting substance) and a transcription factor (SF-1) known to be essential for gonadal development and function. Thus, our results identify GATA-4 as an important regulator of gonadal gene transcription where its specificity of action is mediated through synergistic interactions with other transcription factors such as SF-1.
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Affiliation(s)
- J J Tremblay
- Ontogeny and Reproduction Research Unit, CHUL Research Center, Laval University, Ste-Foy, Québec, Canada G1V 4G2
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Abstract
The Ptx (Pitx) family of homeobox transcription factors comprises Ptx1, Ptx2 and Ptx3. Ptx1 and Ptx2 are expressed in the stomodeum and its derivatives including the pituitary, as well as in mesodermal derivatives, whereas Ptx3 is expressed in one neuronal lineage of the brain and in the eyes. A large set of downstream target genes have been identified for Ptx1 in the pituitary gland where it acts as a pan-pituitary regulator of transcription. In particular, Ptx1 contributes to promoter- and lineage-specific transcription by interaction with cell-restricted factors such as SF-1, Egr-1, Pit1, and the basic helix-loop-helix heterodimer NeuroD1/Pan1. We describe the cloning from pituitary cells and the characterization of a Ptx1 isoform, named Ptx1b, generated by alternative promoter usage. The two Ptx1 and two Ptx2 isoforms have similar in vitro DNA binding specificities and they all activate transcription driven by a panel of pituitary promoters, including those for proopiomelanocortin, alphaGSU, LHbeta, FSHbeta, GnRH-R, TSHbeta, PRL, and GH. Also like Ptx1, the Ptx1b, Ptx2a, and Ptx2b transcription factors synergize with the structurally unrelated factors SF-1, Egr-1, Pit1, and NeuroD1/Pan1 to activate promoter-specific transcription. In conclusion, the pituitary transcriptional activities of the four Ptx isoforms do not appear to be dependent on the variant N-termini of these factors.
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Affiliation(s)
- J J Tremblay
- Laboratoire de génétique moléculaire, Institut de recherches cliniques de Montréal, Canada
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Tremblay JJ, Viger RS. Transcription factor GATA-4 enhances Müllerian inhibiting substance gene transcription through a direct interaction with the nuclear receptor SF-1. Mol Endocrinol 1999; 13:1388-401. [PMID: 10446911 DOI: 10.1210/mend.13.8.0330] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Secretion of Müllerian-inhibiting substance (MIS) by Sertoli cells of the fetal testis and subsequent regression of the Müllerian ducts in the male embryo is a crucial event that contributes to proper sex differentiation. The zinc finger transcription factor GATA-4 and nuclear receptor SF-1 are early markers of Sertoli cells that have been shown to regulate MIS transcription. The fact that the GATA and SF-1 binding sites are adjacent to one another in the MIS promoter raised the possibility that both factors might transcriptionally cooperate to regulate MIS expression. Indeed, coexpression of both factors resulted in a strong synergistic activation of the MIS promoter. GATA-4/SF-1 synergism was the result of a direct protein-protein interaction mediated through the zinc finger region of GATA-4. Remarkably, synergy between GATA-4 and SF-1 on a variety of different SF-1 targets did not absolutely require GATA binding to DNA. Moreover, synergy with SF-1 was also observed with other GATA family members. Thus, these data not only provide a clearer understanding of the molecular mechanisms that control the sex-specific expression of the MIS gene but also reveal a potentially novel mechanism for the regulation of SF-1-dependent genes in tissues where SF-1 and GATA factors are coexpressed.
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Affiliation(s)
- J J Tremblay
- Unité de Recherche en Ontogénie et Reproduction Centre Hospitalier Universitaire de Québec, Pavillon Centre Hospitalier de l'Université Laval, Ste-Foy, Québec, Canada
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11
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Tremblay JJ. Transcription Factor GATA-4 Enhances Mullerian Inhibiting Substance Gene Transcription through a Direct Interaction with the Nuclear Receptor SF-1. Mol Endocrinol 1999. [DOI: 10.1210/me.13.8.1388] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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12
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Abstract
Ptx1 (Pitx1) is a bicoid-related homeobox transcription factor expressed from the onset of pituitary development. It was shown to cooperate with cell-restricted factors, such as Pit1, NeuroD1/PanI and steroidogenic factor 1 (SF-1), to establish a combinatorial code conferring lineage- and promoter-specific gene transcription in the pituitary. Transcriptional synergism between Ptx1 and SF-1 on two SF-1 target genes, pituitary luteinizing hormone beta and Müllerian-inhibiting substance (MIS), requires SF-1 binding to DNA and appears to result from direct physical interaction between these two proteins. The interaction between the C-terminus of Ptx1 and the N-terminal half of SF-1 results in transcriptional enhancement that equals the activity of a constitutively active SF-1 mutant and that may mimic the effect of a still unidentified SF-1 ligand. Thus, the unmasking of SF-1 activity by Ptx1 may represent a developmental mechanism to alleviate the need for SF-1 ligand in transcription and, possibly, at critical times during organogenesis.
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Affiliation(s)
- J J Tremblay
- Laboratoire de Génétique Moléculaire, Institut de Recherches Cliniques de Montréal, 110 des Pins Ouest, Montréal, Québec, Canada H2W 1R7
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13
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Tremblay JJ, Drouin J. Egr-1 is a downstream effector of GnRH and synergizes by direct interaction with Ptx1 and SF-1 to enhance luteinizing hormone beta gene transcription. Mol Cell Biol 1999; 19:2567-76. [PMID: 10082522 PMCID: PMC84049 DOI: 10.1128/mcb.19.4.2567] [Citation(s) in RCA: 214] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pituitary gonadotropins are critical regulators of gonadal development and function. Expression and secretion of the mature hormones are regulated by gonadotropin-releasing hormone (GnRH), which is itself secreted from the hypothalamus. GnRH stimulation of gonadotropin expression and secretion occurs through the G-protein-linked phospholipase C/inositol triphosphate intracellular signaling pathway, which ultimately leads to protein kinase C (PKC) activation and increased intracellular calcium levels. Transcription factors mediating the effects of GnRH-induced signals on transcription of gonadotropin genes have not yet been identified. Recent studies have identified key factors involved in luteinizing hormone beta (LHbeta) gonadotropin gene transcription: the nuclear receptor SF-1, the bicoid-related homeoprotein Ptx1 (Pitx1), and the immediate-early Egr-1 gene. We now show that GnRH is a potent stimulator of Egr-1, but not Ptx1 or SF-1, expression. Further, Egr-1 activation of the LHbeta promoter is specifically enhanced by PKC, in agreement with a role for Egr-1 in mediating a GnRH effect on transcription. Egr-1 interacts directly with Ptx1 and with SF-1, leading to an enhancement of Ptx1- and SF-1-induced LHbeta transcription. Thus, Egr-1 is a likely transcriptional mediator of GnRH-induced signals for activation of the LHbeta gene.
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Affiliation(s)
- J J Tremblay
- Laboratoire de Génétique Moléculaire, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada H2W 1R7
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Abstract
A subfamily of bicoid-related homeodomain factors was recently discovered through its involvement in transcription of pituitary-specific genes. We isolated the first member of this family, Ptxl (pituitary homeobox 1), through its DNA binding properties whereas a second related gene, Ptx2 (RIEG), was identified by positional cloning as the causative gene for Rieger's syndrome. The mechanisms of Ptx action on its target genes as well as its putative roles during development are reviewed with particular emphasis on its role in pituitary function.
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Affiliation(s)
- J Drouin
- Laboratoire de Génétique Moléculaire, Institut de recherches cliniques de Montréal, Québec, Canada.
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15
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Acampora D, Mazan S, Tuorto F, Avantaggiato V, Tremblay JJ, Lazzaro D, di Carlo A, Mariano A, Macchia PE, Corte G, Macchia V, Drouin J, Brûlet P, Simeone A. Transient dwarfism and hypogonadism in mice lacking Otx1 reveal prepubescent stage-specific control of pituitary levels of GH, FSH and LH. Development 1998; 125:1229-39. [PMID: 9477321 DOI: 10.1242/dev.125.7.1229] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Genetic and molecular approaches have enabled the identification of regulatory genes critically involved in determining cell types in the pituitary gland and/or in the hypothalamus. Here we report that Otx1, a homeobox-containing gene of the Otx gene family, is postnatally transcribed and translated in the pituitary gland. Cell culture experiments indicate that Otx1 may activate transcription of the growth hormone (GH), follicle-stimulating hormone (betaFSH), luteinizing hormone (betaLH) and alpha-glycoprotein subunit (alphaGSU) genes. Analysis of Otx1 null mice indicates that, at the prepubescent stage, they exhibit transient dwarfism and hypogonadism due to low levels of pituitary GH, FSH and LH hormones which, in turn, dramatically affect downstream molecular and organ targets. Nevertheless, Otx1−/− mice gradually recover from most of these abnormalities, showing normal levels of pituitary hormones with restored growth and gonadal function at 4 months of age. Expression patterns of related hypothalamic and pituitary cell type restricted genes, growth hormone releasing hormone (GRH), gonadotropin releasing hormone (GnRH) and their pituitary receptors (GRHR and GnRHR) suggest that, in Otx1−/− mice, hypothalamic and pituitary cells of the somatotropic and gonadotropic lineages appear unaltered and that the ability to synthesize GH, FSH and LH, rather than the number of cells producing these hormones, is affected. Our data indicate that Otx1 is a new pituitary transcription factor involved at the prepubescent stage in the control of GH, FSH and LH hormone levels and suggest that a complex regulatory mechanism might exist to control the physiological need for pituitary hormones at specific postnatal stages.
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Affiliation(s)
- D Acampora
- International Institute of Genetics and Biophysics, CNR, Naples, Italy
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Tremblay JJ, Lanctôt C, Drouin J. The pan-pituitary activator of transcription, Ptx1 (pituitary homeobox 1), acts in synergy with SF-1 and Pit1 and is an upstream regulator of the Lim-homeodomain gene Lim3/Lhx3. Mol Endocrinol 1998; 12:428-41. [PMID: 9514159 DOI: 10.1210/mend.12.3.0073] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Ptx1 (pituitary homeobox 1) homeobox transcription factor was isolated as a transcription factor of the pituitary POMC gene. In corticotrope cells that express POMC, cell-specific transcription is conferred in part by the synergistic action of Ptx1 with the basic helix-loop-helix factor NeuroD1. Since Ptx1 expression precedes pituitary development and differentiation, we investigated its expression and function in other pituitary lineages. Ptx1 is expressed in most pituitary-derived cell lines and as is the related Ptx2 (Rieger) gene. However, Ptx1 appears to be the only Ptx protein in corticotropes and the predominant one in gonadotrope cells. Most pituitary hormone-coding gene promoters are activated by Ptx1. Thus, Ptx1 appears to be a general regulator of pituitary-specific transcription. In addition, Ptx1 action is synergized by cell-restricted transcription factors to confer promoter-specific expression. Indeed, in the somatolactotrope lineage, synergism between Ptx1 and Pit1 is observed on the PRL promoter, and strong synergism between Ptx1 and SF-1 is observed in gonadotrope cells on the betaLH promoter but not on the alphaGSU (glycoprotein hormone alpha-subunit gene) and betaFSH promoters. Synergism between these two classes of factors is reminiscent of the interaction between the products of the Drosophila genes Ftz (fushi tarazu) and Ftz-F1. Antisense RNA experiments performed in alphaT3-1 cells that express the alphaGSU gene showed that expression of endogenous alphaGSU is highly dependent on Ptx1 whereas many other genes are not affected. Interestingly, the only other gene found to be highly dependent on Ptx1 for expression was the gene for the Lim3/Lhx3 transcription factor. Thus, these experiments place Ptx1 upstream of Lim3/Lhx3 in a cascade of regulators that appear to work in a combinatorial code to direct pituitary-, lineage-, and promoter-specific transcription.
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Affiliation(s)
- J J Tremblay
- Laboratoire de Génétique Moléculaire, Institut de Recherches Cliniques de Montréal, Québec, Canada
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Smidt MP, van Schaick HS, Lanctôt C, Tremblay JJ, Cox JJ, van der Kleij AA, Wolterink G, Drouin J, Burbach JP. A homeodomain gene Ptx3 has highly restricted brain expression in mesencephalic dopaminergic neurons. Proc Natl Acad Sci U S A 1997; 94:13305-10. [PMID: 9371841 PMCID: PMC24304 DOI: 10.1073/pnas.94.24.13305] [Citation(s) in RCA: 306] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The mesencephalic dopaminergic (mesDA) system regulates behavior and movement control and has been implicated in psychiatric and affective disorders. We have identified a bicoid-related homeobox gene, Ptx3, a member of the Ptx-subfamily, that is uniquely expressed in these neurons. Its expression starting at E11.5 in the developing mouse midbrain correlates with the appearance of mesDA neurons. The number of Ptx3-expressing neurons is reduced in Parkinson patients, and these neurons are absent from 6-hydroxydopamine-lesioned rats, an animal model for this disease. Thus, Ptx3 is a unique transcription factor marking the mesDA neurons at the exclusion of other dopaminergic neurons, and it may be involved in developmental determination of this neuronal lineage.
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Affiliation(s)
- M P Smidt
- Rudolf Magnus Institute for Neurosciences, Department of Medical Pharmacology, Medical Faculty, Utrecht University, The Netherlands
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Crawford MJ, Lanctôt C, Tremblay JJ, Jenkins N, Gilbert D, Copeland N, Beatty B, Drouin J. Human and murine PTX1/Ptx1 gene maps to the region for Treacher Collins syndrome. Mamm Genome 1997; 8:841-5. [PMID: 9337397 DOI: 10.1007/s003359900589] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ptx1 belongs to an expanding family of bicoid-related vertebrate homeobox genes. These genes, like their Drosophila homolog, seem to play a role in the development of anterior structures and, in particular, the brain and facies. We report the chromosomal localization of mouse Ptx1, and the cloning, sequencing, and chromosomal localization of the human homolog PTX1. The putative encoded proteins share 100% homology in the homeodomain and are 88% and 97% conserved in the N- and C-termini respectively. Intron/exon boundaries are also conserved. Murine Ptx1 was localized, by interspecific backcrossing, to Chr 13 within 2.6 cM of Caml. The gene resides centrally on Chromosome (Chr) 13 in a region syntenic with human Chr 5q. Subsequent analysis by fluorescent in situ hybridization places the human gene, PTX1, on 5q31, a region associated with Treacher Collins Franceschetti Syndrome. Taken together with the craniofacial expression pattern of Ptx1 during early development, the localization of the gene in this chromosomal area is consistent with an involvement in Treacher Collins Franceschetti Syndrome.
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Affiliation(s)
- M J Crawford
- Laboratoire de génétique moléculaire, Institut de recherches cliniques de Montréal (IRCM), Québec, Canada
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Lamonerie T, Tremblay JJ, Lanctôt C, Therrien M, Gauthier Y, Drouin J. Ptx1, a bicoid-related homeo box transcription factor involved in transcription of the pro-opiomelanocortin gene. Genes Dev 1996; 10:1284-95. [PMID: 8675014 DOI: 10.1101/gad.10.10.1284] [Citation(s) in RCA: 331] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The pituitary gland contains six distinct hormone-producing cell types that arise sequentially during organogenesis. The first cells to differentiate are those that express the pro-opiomelanocortin (POMC) gene in the anterior pituitary lobe. The other lineages, which appear later, include cells that are dependent on the POU factor Pit-1 and another POMC-expressing lineage in the intermediate pituitary lobe. Using AtT-20 cells as a model for early expression of POMC in the anterior pituitary, we have defined a regulatory element conferring cell specificity of transcription and cloned a cognate transcription factor. This factor, Ptx1 (pituitary homeo box 1), contains a homeo box related to those of the anterior-specific genes bicoid and orthodenticle in Drosophila, and Otx-1 and Otx-2 in mammals. Ptx1 activates transcription upon binding a sequence related to the Drosophila bicoid target sites. Ptx1 is the only nuclear factor of this DNA-binding specificity that is detected in AtT-20 cells, and it is expressed at high levels in a subset of adult anterior pituitary cells that express POMC. However, Ptx1 is expressed in most cells of Rathke's pouch at an early time during pituitary development and before final differentiation of hormone-producing cells. Thus, Ptx1 may have a role in differentiation of pituitary cells, and its early expression pattern suggests that it may have a role in pituitary formation. In the adult pituitary gland, Ptx1 appears to be recruited for cell-specific transcription of the POMC gene.
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Affiliation(s)
- T Lamonerie
- Laboratoire de Génétique Moléculaire, Institut de Recherches Cliniquesde Montréal, Québec, Canada
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