151
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Koubova J, Menke DB, Zhou Q, Capel B, Griswold MD, Page DC. Retinoic acid regulates sex-specific timing of meiotic initiation in mice. Proc Natl Acad Sci U S A 2006; 103:2474-9. [PMID: 16461896 PMCID: PMC1413806 DOI: 10.1073/pnas.0510813103] [Citation(s) in RCA: 657] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In mammals, meiosis is initiated at different time points in males and females, but the mechanism underlying this difference is unknown. Female germ cells begin meiosis during embryogenesis. In males, embryonic germ cells undergo G0/G1 mitotic cell cycle arrest, and meiosis begins after birth. In mice, the Stimulated by Retinoic Acid Gene 8 (Stra8) has been found to be required for the transition into meiosis in both female and male germ cells. Stra8 is expressed in embryonic ovaries just before meiotic initiation, whereas its expression in testes is first detected after birth. Here we examine the mechanism underlying the sex-specific timing of Stra8 expression and meiotic initiation in mice. Our work shows that signaling by retinoic acid (RA), an active derivative of vitamin A, is required for Stra8 expression and thereby meiotic initiation in embryonic ovaries. We also discovered that RA is sufficient to induce Stra8 expression in embryonic testes and in vitamin A-deficient adult testes in vivo. Finally, our results show that cytochrome p450 (CYP)-mediated RA metabolism prevents premature Stra8 expression in embryonic testes. Treatment with an inhibitor specific to RA-metabolizing enzymes indicates that a cytochrome p450 from the 26 family (CYP26) is responsible for delaying Stra8 expression in embryonic testes. Sex-specific regulation of RA signaling thus plays an essential role in meiotic initiation in embryonic ovaries and precludes its occurrence in embryonic testes. Because RA signaling regulates Stra8 expression in both embryonic ovaries and adult testes, this portion of the meiotic initiation pathway may be identical in both sexes.
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Affiliation(s)
- Jana Koubova
- *Howard Hughes Medical Institute, Whitehead Institute, and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Douglas B. Menke
- *Howard Hughes Medical Institute, Whitehead Institute, and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Qing Zhou
- Center for Reproductive Biology, School of Molecular Biosciences, Washingston State University, Pullman, WA 99164; and
| | - Blanche Capel
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710
| | - Michael D. Griswold
- Center for Reproductive Biology, School of Molecular Biosciences, Washingston State University, Pullman, WA 99164; and
| | - David C. Page
- *Howard Hughes Medical Institute, Whitehead Institute, and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
- To whom correspondence should be addressed. E-mail:
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152
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Mahood IK, McKinnell C, Walker M, Hallmark N, Scott H, Fisher JS, Rivas A, Hartung S, Ivell R, Mason JI, Sharpe RM. Cellular origins of testicular dysgenesis in rats exposed in utero to di(n-butyl) phthalate. ACTA ACUST UNITED AC 2006; 29:148-54; discussion 181-5. [PMID: 16466534 DOI: 10.1111/j.1365-2605.2005.00574.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Foetal exposure of male rats to di(n-butyl) phthalate (DBP) induces testicular changes similar to testicular dysgenesis syndrome in humans, including the formation of focal 'dysgenetic areas' within post-natal testes, surrounded by otherwise normal tubules exhibiting complete spermatogenesis. We hypothesize that these dysgenetic areas form when Sertoli (and other) cells are 'trapped' during the abnormal formation of large Leydig cell (LC) clusters in foetal life and by post-natal day (d) 4 these groups of intermingled cells attempt to form seminiferous tubules. It is likely that the malformed tubules resulting correspond to the dysgenetic areas evident in later life. This also provides a plausible explanation for the occurrence of LCs within seminiferous cords/tubules in or bordering the dysgenetic areas. In our previous studies intratubular LCs (ITLCs) were identified by immunostaining for 3beta-hydroxysteroid dehydrogenase (3beta-HSD), the definitive LC cytoplasmic marker. However, the possibility remained that the 'presumptive' ITLCs were in fact Sertoli cells that had aberrantly gained the ability to express 3beta-HSD. Therefore, the aim of the present study was to fully characterize the ITLCs induced by in utero DBP exposure in d25 rats using a number of LC- (3beta-HSD, P450 side-chain cleavage enzyme, insulin-like factor 3, oestrogen receptor alpha) and Sertoli cell- (vimentin, Wilm's tumour-1) specific markers. Our results show that ITLCs express all four LC-specific markers but do not express either of the Sertoli cell markers. It is therefore concluded that the ITLCs are bona fide LCs that are abnormally located within the seminiferous tubules of DBP-exposed rats in post-natal life.
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Affiliation(s)
- I Kim Mahood
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, UK.
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153
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Yao HHC, Aardema J, Holthusen K. Sexually dimorphic regulation of inhibin beta B in establishing gonadal vasculature in mice. Biol Reprod 2006; 74:978-83. [PMID: 16452457 PMCID: PMC1819406 DOI: 10.1095/biolreprod.105.050286] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Sexually dimorphic differentiation of gonads is accomplished through balanced interactions between positive and negative regulators. One of the earliest features of gonadal differentiation is the divergent patterning of the vasculature. A male-specific coelomic vessel develops on the anterior to posterior of the XY gonad, whereas this vessel is absent in XX gonads. It is postulated that the testis-determining gene Sry controls formation of the coelomic vessel, but the exact molecular mechanism remains unknown. Here we reveal a novel role for inhibin beta B in establishing sex-specific gonad vasculature. In the testis, inhibin beta B contributes to proper formation of the coelomic vessel, a male-specific artery critical for testis development and, later in development, hormone transportation. On the other hand, in the ovary, inhibin beta B is repressed by WNT4 and its downstream target follistatin, leading to the absence of the coelomic vessel. When either Wnt4 or follistatin was inactivated, the coelomic vessel appeared ectopically in the XX ovary. However, when inhibin beta B was also removed in either the Wnt4-null or follistatin-null background, normal ovarian development was restored and no coelomic vessel was found. Our results indicate that the sex-specific formation of the coelomic vessel is established by positive components in the testis as well as an antagonizing pathway from the ovary. Inhibin beta B is strategically positioned at the intersection of these opposing pathways.
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Affiliation(s)
- Humphrey Hung-Chang Yao
- Department of Veterinary Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA.
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154
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Beverdam A, Koopman P. Expression profiling of purified mouse gonadal somatic cells during the critical time window of sex determination reveals novel candidate genes for human sexual dysgenesis syndromes. Hum Mol Genet 2006; 15:417-31. [PMID: 16399799 DOI: 10.1093/hmg/ddi463] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Despite the identification of SRY as the testis-determining gene in mammals, the genetic interactions controlling the earliest steps of male sex determination remain poorly understood. In particular, the molecular lesions underlying a high proportion of human XY gonadal dysgenesis, XX maleness and XX true hermaphroditism remain undiscovered. A number of screens have identified candidate genes whose expression is modulated during testis or ovary differentiation in mice, but these screens have used whole gonads, consisting of multiple cell types, or stages of gonadal development well beyond the time of sex determination. We describe here a novel reporter mouse line that expresses enhanced green fluorescent protein under the control of an Sf1 promoter fragment, marking Sertoli and granulosa cell precursors during the critical period of sex determination. These cells were purified from gonads of male and female transgenic embryos at 10.5 dpc (shortly after Sry transcription is activated) and 11.5 dpc (when Sox9 transcription begins), and their transcriptomes analysed using Affymetrix genome arrays. We identified 266 genes, including Dhh, Fgf9 and Ptgds, that were upregulated and 50 genes that were downregulated in 11.5 dpc male somatic gonad cells only, and 242 genes, including Fst, that were upregulated in 11.5 dpc female somatic gonad cells only. The majority of these genes are novel genes that lack identifiable homology, and several human orthologues were found to map to chromosomal loci implicated in disorders of sexual development. These genes represent an important resource with which to piece together the earliest steps of sex determination and gonad development, and provide new candidates for mutation searching in human sexual dysgenesis syndromes.
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Affiliation(s)
- Annemiek Beverdam
- Division of Genetics and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia
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155
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Wilhelm D, Martinson F, Bradford S, Wilson MJ, Combes AN, Beverdam A, Bowles J, Mizusaki H, Koopman P. Sertoli cell differentiation is induced both cell-autonomously and through prostaglandin signaling during mammalian sex determination. Dev Biol 2005; 287:111-24. [PMID: 16185683 DOI: 10.1016/j.ydbio.2005.08.039] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 08/18/2005] [Accepted: 08/22/2005] [Indexed: 11/22/2022]
Abstract
We have raised an antibody specifically recognizing endogenous mouse SRY protein and used it to investigate the molecular and cellular mode of action of SRY in testis determination. We find that expression of SRY protein closely mirrors the expression of Sry mRNA in mouse genital ridges and is detectable for 6 to 8 h after the mRNA ceases to be detectable. The subset of somatic cells that expresses SRY begins to express SOX9 almost immediately. Since these SOX9-positive cells go on to develop as Sertoli cells, it appears that SRY expression marks the pre-Sertoli cell lineage and leads to up-regulation of Sox9 expression cell-autonomously. However, a small proportion of SOX9-positive cells did not appear to express SRY, possibly reflecting the additional involvement of paracrine signaling in activating Sox9 transcription in these cells. We confirmed by ex vivo cell mixing experiments that SRY is able to engage receptor-mediated signaling to up-regulate Sox9 expression. Finally, we showed by employing specific inhibitors that the causative signaling molecule is prostaglandin D2 (PGD2) and that PGD2 can induce Sox9 transcription in cultured XX gonads. Our data indicate a mechanism whereby Sry uses both a cell-autonomous mechanism and a PGD2-mediated signaling mechanism to stimulate expression of Sox9 and induce the differentiation of Sertoli cells in vivo.
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Affiliation(s)
- Dagmar Wilhelm
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia
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156
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Smith CA, McClive PJ, Hudson Q, Sinclair AH. Male-specific cell migration into the developing gonad is a conserved process involving PDGF signalling. Dev Biol 2005; 284:337-50. [PMID: 16005453 DOI: 10.1016/j.ydbio.2005.05.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 05/23/2005] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
Male-specific migration of cells from the mesonephric kidney into the embryonic gonad is required for testis formation in the mouse. It is unknown, however, whether this process is specific to the mouse embryo or whether it is a fundamental characteristic of testis formation in other vertebrates. The signalling molecule/s underlying the process are also unclear. It has previously been speculated that male-specific cell migration might be limited to mammals. Here, we report that male-specific cell migration is conserved between mammals (mouse) and birds (quail-chicken) and that it involves proper PDGF signalling in both groups. Interspecific co-cultures of embryonic quail mesonephric kidneys together with embryonic chicken gonads showed that quail cells migrated specifically into male chicken gonads at the time of sexual differentiation. The migration process is therefore conserved in birds. Furthermore, this migration involves a conserved signalling pathway/s. When GFP-labelled embryonic mouse mesonephric kidneys were cultured together with embryonic chicken gonads, GFP+ mouse cells migrated specifically into male chicken gonads and not female gonads. The immigrating mouse cells contributed to the interstitial cell population of the developing chicken testis, with most cells expressing the endothelial cell marker, PECAM. The signalling molecule/s released from the embryonic male chicken gonad is therefore recognised by both embryonic quail and mouse mesonephric cells. A candidate signalling molecule mediating the male-specific cell migration is PDGF. We found that PDGF-A and PDGF receptor-alpha are both up-regulated male-specifically in embryonic chicken and mouse gonads. PDGF signalling involves the phosphotidylinositol 3-kinase (PIK3) pathway, an intracellular pathway proposed to be important for mesonephric cell migration in the mammalian gonad. We found that a component of this pathway, PI3KC2alpha, is expressed male-specifically in developing embryonic chicken gonads at the time of sexual differentiation. Treatment of organ cultures with the selective PDGF receptor signalling inhibitor, AG1296 (tyrphostin), blocked or impaired mesonephric cell migration in both the mammalian and avian systems. Taken together, these studies indicate that a key cellular event in gonadal sex differentiation is conserved among higher vertebrates, that it involves PDGF signalling, and that in mammals is an indirect effect of Sry expression.
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Affiliation(s)
- Craig A Smith
- Department of Paediatrics and Murdoch Children's Research Institute, The University of Melbourne, Royal Children's Hospital, Melbourne, Victoria 3052, Australia
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157
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Kanai Y, Hiramatsu R, Matoba S, Kidokoro T. From SRY to SOX9: Mammalian Testis Differentiation. ACTA ACUST UNITED AC 2005; 138:13-9. [PMID: 16046443 DOI: 10.1093/jb/mvi098] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Sry (sex-determining region on the Y chromosome) is a master gene that initiates testis differentiation of the bipotential indifferent gonad in mammals. In mice, Sry expression is transiently activated in a center-to-pole wave along the anteroposterior (AP) axis of developing XY gonads. Shortly after the onset of Sry activation, Sox9 (Sry-related HMG box-9), a fundamental testis-differentiation gene common to all vertebrates, is also activated in a center-to-pole pattern similar to the initial Sry expression profile. Several male-specific cellular events, such as glycogenesis, coelomic epithelium proliferation, mesonephric migration and vasculogenesis, are induced in XY gonads following the onset of Sry and Sox9 expression. This paper mainly focuses on recent advances in elucidating the regulatory mechanisms of Sry and Sox9 expression and male-specific cellular events immediately downstream of SRY action during the initial phases of testis differentiation.
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Affiliation(s)
- Yoshiakira Kanai
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Tokyo 113-8657.
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158
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Yao HHC, Capel B. Temperature, genes, and sex: a comparative view of sex determination in Trachemys scripta and Mus musculus. J Biochem 2005; 138:5-12. [PMID: 16046442 PMCID: PMC4066379 DOI: 10.1093/jb/mvi097] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Sex determination, the step at which differentiation of males and females is initiated in the embryo, is of central importance to the propagation of species. There is a remarkable diversity of mechanisms by which sex determination is accomplished. In general these mechanisms fall into two categories: Genetic Sex Determination (GSD), which depends on genetic differences between the sexes, and Environmental Sex Determination (ESD), which depends on extrinsic cues. In this review we will consider these two means of determining sex with particular emphasis on two species: a species that depends on GSD, Mus musculus, and a species that depends on ESD, Trachemys scripta. Because the structural organization of the adult testis and ovary is very similar across vertebrates, most biologists had expected that the pathways downstream of the sex-determining switch would be conserved. However, emerging data indicate that not only are the initial sex determining mechanisms different, but the downstream pathways and morphogenetic events leading to the development of a testis or ovary also are different.
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Affiliation(s)
- Humphrey H-C Yao
- Department of Veterinary Biosciences, University of Illinois at Urbana-Champaign
| | - Blanche Capel
- Department of Cell Biology, Duke University Medical Center
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159
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Bouma GJ, Albrecht KH, Washburn LL, Recknagel AK, Churchill GA, Eicher EM. Gonadal sex reversal in mutantDax1XY mice: a failure to upregulateSox9in pre-Sertoli cells. Development 2005; 132:3045-54. [PMID: 15944188 DOI: 10.1242/dev.01890] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The nuclear receptor transcription factor Dax1 is hypothesized to play a role in testicular development, although the mechanism of its action is unknown. Here, we present evidence that Dax1 plays an early essential role in fetal testis development. We hypothesize that upregulation of Sox9 expression in precursor somatic cells, a process required for their differentiation as Sertoli cells, depends on the coordinated expression of Dax1, Sry and another gene, Tda1. Our conclusion and model are based on the following experimental findings: (1) presence of a mutant Dax1 allele (Dax1-) results in complete gonadal sex reversal in C57BL/6JEi (B6) XY mice, whereas testes develop in DBA/2J (D2) and(B6×D2)F1 XY mice; (2) B6-DAX1 sex reversal is inherited as a complex trait that includes the chromosome 4 gene Tda1; (3) B6 Dax1-/Y fetal gonads initiate development as ovaries, even though Sry expression is activated at the correct time and at appropriate levels; (4) upregulation of Sox9 does not occur in B6 Dax1-/Y fetal gonads in spite of apparently normal Sryexpression; and (5) overexpression of Sry in B6 Dax1-/Y fetal gonads upregulates Sox9 and corrects testis development.
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160
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Viger RS, Silversides DW, Tremblay JJ. New insights into the regulation of mammalian sex determination and male sex differentiation. VITAMINS AND HORMONES 2005; 70:387-413. [PMID: 15727812 DOI: 10.1016/s0083-6729(05)70013-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
In mammals, sex development is a genetically and hormonally controlled process that begins with the establishment of chromosomal or genetic sex (XY or XX) at conception. At approximately 6 to 7 weeks of human gestation or embryonic day e11.5 in the mouse, expression of the Y chromosome-linked sex determining gene called SRY (described in detail in this chapter) then initiates gonadal differentiation, which is the formation of either a testis (male) or an ovary (female). Male sex differentiation (development of internal and external reproductive organs and acquisition of male secondary sex characteristics) is then controlled by three principal hormones produced by the testis: Mullerian inhibiting substance (MIS) or anti-Mullerian hormone (AMH), testosterone, and insulin-like factor 3 (INSL3). In the absence of these critical testicular hormones, female sex differentiation ensues. This sequential, three-step process of mammalian sex development is also known as the Jost paradigm. With the advent of modern biotechnologies over the past decade, such as transgenics, array-based gene profiling, and proteomics, the field of mammalian sex determination has witnessed a remarkable boost in the understanding of the genetics and complex molecular mechanisms that regulate this fundamental biological event. Consequently, a number of excellent reviews have been devoted to this topic. The purpose of the present chapter is to provide an overview of selected aspects of mammalian sex determination and differentiation with an emphasis on studies that have marked this field of study.
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Affiliation(s)
- Robert S Viger
- Ontogeny-Reproduction Research Unit, CHUL Research Centre, Department of Obstetrics and Gynecology, Faculty of Medicine, Laval University, Ste-Foy, Québec G1V 4G2, Canada
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161
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van Bragt MPA, Ciliberti N, Stanford WL, de Rooij DG, van Pelt AMM. LY6A/E (SCA-1) expression in the mouse testis. Biol Reprod 2005; 73:634-8. [PMID: 15930324 DOI: 10.1095/biolreprod.105.040303] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Recently, it was found by two research groups that LY6A, known widely in the stem cell community as stem cell antigen-1 or SCA-1, is expressed on testicular side population (SP) cells. Whether these SP cells are spermatogonial stem cells is a point of disagreement and, therefore, the identity of the LY6A-positive cells as well. We studied the expression pattern of LY6A in testis by immunohistochemistry and found it to be expressed in the interstitial tissue on peritubular myoid, endothelial, and spherical-shaped peritubular mesenchymal cells. To address the question whether LY6A has a function in spermatogenesis or testis development, we studied the testis of Ly6a(-/-) mice (allele Ly6a(tm1Pmf)). We found no morphological abnormalities or differences in numbers of spermatogonia, spermatocytes, Leydig cells, or macrophages in relation to the number of Sertoli cells. Therefore, we conclude that LY6A expression does not influence testis development or spermatogenesis and that spermatogonial stem cells are LY6A negative.
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Affiliation(s)
- Maaike P A van Bragt
- Department of Endocrinology, Faculty of Biology, Utrecht University, The Netherlands.
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162
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Malki S, Nef S, Notarnicola C, Thevenet L, Gasca S, Méjean C, Berta P, Poulat F, Boizet-Bonhoure B. Prostaglandin D2 induces nuclear import of the sex-determining factor SOX9 via its cAMP-PKA phosphorylation. EMBO J 2005; 24:1798-809. [PMID: 15889150 PMCID: PMC1142593 DOI: 10.1038/sj.emboj.7600660] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Accepted: 04/05/2005] [Indexed: 01/23/2023] Open
Abstract
During mammalian gonadal development, nuclear import/export of the transcription factor SOX9 is a critical step of the Sry-initiated testis-determining cascade. In this study, we identify a molecular mechanism contributing to the SOX9 nuclear translocation in NT2/D1 cells, which is mediated by the prostaglandin D2 (PGD2) signalling pathway via stimulation of its adenylcyclase-coupled DP1 receptor. We find that activation of cAMP-dependent protein kinase A (PKA) induces phosphorylation of SOX9 on its two S64 and S181 PKA sites, and its nuclear localization by enhancing SOX9 binding to the nucleocytoplasmic transport protein importin beta. Moreover, in embryonic gonads, we detect a male-specific prostaglandin D synthase expression and an active PGD2 signal at the time and place of SOX9 expression. We thus propose a new step in the sex-determining cascade where PGD2 acts as an autocrine factor inducing SOX9 nuclear translocation and subsequent Sertoli cell differentiation.
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Affiliation(s)
- Safia Malki
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
| | - Serge Nef
- Department of Genetic Medicine and Development, University of Geneva Medical School, rue Michel-Servet, Geneva, Switzerland
| | - Cécile Notarnicola
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
| | - Laurie Thevenet
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
| | - Stéphan Gasca
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
| | - Catherine Méjean
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
| | - Philippe Berta
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
| | - Francis Poulat
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
| | - Brigitte Boizet-Bonhoure
- Institut de Génétique Humaine, CNRS UPR1142, rue de la Cardonille, Montpellier Cedex, France
- Institut de Génétique Humaine, CNRS UPR1142, 141, rue de la Cardonille, Montpellier Cedex 5, 34396, France. Tel.: +33 4 99 61 99 40; Fax: +33 4 99 61 99 42; E-mail:
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163
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Yao HHC, DiNapoli L, Capel B. Cellular mechanisms of sex determination in the red-eared slider turtle, Trachemys scripta. Mech Dev 2005; 121:1393-401. [PMID: 15454268 PMCID: PMC4067764 DOI: 10.1016/j.mod.2004.06.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 06/02/2004] [Accepted: 06/02/2004] [Indexed: 11/15/2022]
Abstract
In all vertebrates sex determination is the step at which development of a testis or ovary is initiated in the bipotential gonad. Although Mus musculus and the red-eared slider turtle, Trachemys scripta, use different mechanisms to initiate organogenesis of the testis (the Y-linked gene, Sry, in the mouse vs. the incubation temperature of the egg in the turtle), the structure of the adult testis is strikingly similar. We have identified several cellular mechanisms involved in testis organogenesis in mouse. Here we investigated whether these cellular mechanisms are conserved in T. scripta downstream of the temperature-dependent switch. Cell tracing experiments indicated that the coelomic epithelium in T. scripta contributes precursors for Sertoli cells and interstitial cells as in mouse. However, we detect no male-specific mesonephric cell migration, a process required for the de novo testis cord-forming process in mouse. In contrast to mouse gonads, where no cord structure is discernible until after the divergence of testis development, we find that primitive sex cords continuous with the coelomic epithelium exist in all T. scripta gonads from the earliest bipotential stages examined. We conclude that typical testis architecture results from the maintenance and elaboration of primitive sex cords in T. scripta rather than the assembly of de novo structures as in mouse.
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Affiliation(s)
| | | | - Blanche Capel
- Corresponding author. Tel.: +1-919-684-6290; fax: +1-919-684-5481. (B. Capel)
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164
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Matoba S, Kanai Y, Kidokoro T, Kanai-Azuma M, Kawakami H, Hayashi Y, Kurohmaru M. A novel Sry-downstream cellular event which preserves the readily available energy source of glycogen in mouse sex differentiation. J Cell Sci 2005; 118:1449-59. [PMID: 15769848 DOI: 10.1242/jcs.01738] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sry is transiently activated in pre-Sertoli cells of the gonadal ridge to initiate testis differentiation in mice. In pre-Sertoli cells, however, the cellular events induced immediately after the onset of Sry expression remain largely unknown. Here we show that testis-specific glycogen accumulation in pre-Sertoli cells is one of the earliest cellular events downstream of Sry action. In developing XY gonads, glycogen accumulation starts to occur in pre-Sertoli cells from around 11.15 dpc (tail somite 14 stage) in a center-to-pole pattern similar to the initial Sry expression profile. Glycogen accumulation was also found in XX male gonads of Sry-transgenic embryos, but not in XX female gonads of wildtype embryos at any developmental stage. In vitro analyses using various culture conditions suggest that testis-specific glycogen deposition is a tissue-autonomous event that can be induced even in serum-free conditions and in a culture of gonadal explants without adjacent mesonephros. Moreover, glycogen accumulation in pre-Sertoli cells was significantly inhibited in vitro by the PI3K inhibitor LY294002, but not by the MEK inhibitor PD98059. Active phospho-AKT (PI3K effector) showed a high degree of accumulation in gonadal somatic cells of genital ridges in a testis-specific manner, both in vitro and in vivo. Therefore, these findings suggest that immediately after the onset of Sry expression, activation of the PI3K-AKT pathway promotes testis-specific glycogen storage in pre-Sertoli cells. To the best of our knowledge, this is a novel Sry-downstream cellular event which preserves this readily available energy source in Sertoli cells for testis-specific morphogenesis and hormone production.
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Affiliation(s)
- Shogo Matoba
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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165
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Yoshioka H, Ishimaru Y, Sugiyama N, Tsunekawa N, Noce T, Kasahara M, Morohashi KI. Mesonephric FGF signaling is associated with the development of sexually indifferent gonadal primordium in chick embryos. Dev Biol 2005; 280:150-61. [PMID: 15766755 DOI: 10.1016/j.ydbio.2005.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 01/11/2005] [Accepted: 01/12/2005] [Indexed: 11/18/2022]
Abstract
The gonad as well as the reproductive tracts, kidney, and adrenal cortex are derived from the intermediate mesoderm. In addition, the intermediate mesoderm forms the mesonephros. Although the mesonephros is the source of certain testicular cell types, its contribution to gonad formation through expression of growth factors is largely unknown. Here, we examined the expression profiles of FGF9 in the developing mesonephros of chick embryos at sexually indifferent stages, and found that the expression domain is adjacent to the gonadal primordium. Moreover, FGFR3 (FGF receptor 3) showed a strong expression in the gonadal primordium. Next, we examined the functions of FGF signal during gonadal development with misexpressed FGF9. Interestingly, misexpression of FGF9 led to gonadal expansion through stimulation of cell proliferation. In contrast, treatment with a chemical inhibitor for FGFR decreased cell proliferation and resulted in reduction of the gonadal size. Simultaneously, the treatment resulted in reduction of gonadal marker gene expression. Our study demonstrated that FGF expressed in the developing mesonephros is involved in the development of the gonad at the sexually indifferent stages through stimulation of gonadal cell proliferation and gonadal marker gene expression.
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Affiliation(s)
- Hidefumi Yoshioka
- Department of Natural Sciences, Hyogo University of Teacher Education, 942-1, Yashiro-cho, Kato Gun, Hyogo 673-1494, Japan
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166
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Abstract
The embryonic gonad is undifferentiated in males and females until a critical stage when the sex chromosomes dictate its development as a testis or ovary. This binary developmental process provides a unique opportunity to delineate the molecular pathways that lead to distinctly different tissues. The testis comprises three main cell types: Sertoli cells, Leydig cells, and germ cells. The Sertoli cells and germ cells reside in seminiferous tubules where spermatogenesis occurs. The Leydig cells populate the interstitial compartment and produce testosterone. The ovary also comprises three main cell types: granulosa cells, theca cells, and oocytes. The oocytes are surrounded by granulosa and theca cells in follicles that grow and differentiate during characteristic reproductive cycles. In this review, we summarize the molecular pathways that regulate the distinct differentiation of these cell types in the developing testis and ovary. In particular, we focus on the transcription factors that initiate these cascades. Although most of the early insights into the sex determination pathway were based on human mutations, targeted mutagenesis in mouse models has revealed key roles for genes not anticipated to regulate gonadal development. Defining these molecular pathways provides the foundation for understanding this critical developmental event and provides new insight into the causes of gonadal dysgenesis.
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Affiliation(s)
- Susan Y Park
- Division of Endocrinology, Metabolism, and Molecular Medicine, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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167
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Mendes SC, Robin C, Dzierzak E. Mesenchymal progenitor cells localize within hematopoietic sites throughout ontogeny. Development 2005; 132:1127-36. [PMID: 15689383 DOI: 10.1242/dev.01615] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mesenchymal stem cells (MSCs) have great clinical potential for the replacement and regeneration of diseased or damaged tissue. They are especially important in the production of the hematopoietic microenvironment, which regulates the maintenance and differentiation of hematopoietic stem cells (HSCs). In the adult, MSCs and their differentiating progeny are found predominantly in the bone marrow (BM). However, it is as yet unknown in which embryonic tissues MSCs reside and whether there is a localized association of these cells within hematopoietic sites during development. To investigate the embryonic origins of these cells, we performed anatomical mapping and frequency analysis of mesenchymal progenitors at several stages of mouse ontogeny. We report here the presence of mesenchymal progenitors, with the potential to differentiate into cells of the osteogenic, adipogenic and chondrogenic lineages, in most of the sites harboring hematopoietic cells. They first appear in the aorta-gonad-mesonephros (AGM) region at the time of HSC emergence. However, at this developmental stage, their presence is independent of HSC activity. They increase numerically during development to a plateau level found in adult BM. Additionally, mesenchymal progenitors are found in the embryonic circulation. Taken together, these data show a co-localization of mesenchymal progenitor/stem cells to the major hematopoietic territories, suggesting that, as development proceeds, mesenchymal progenitors expand within these potent hematopoietic sites.
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Affiliation(s)
- Sandra C Mendes
- Department of Cell Biology and Genetics, Erasmus University Medical Center, PO Box 1738, 3000 DR, Rotterdam, The Netherlands
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168
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Smith CA, McClive PJ, Sinclair AH. Temporal and spatial expression profile of the novelarmadillo-related gene,Alex2, during testicular differentiation in the mouse embryo. Dev Dyn 2005; 233:188-93. [PMID: 15759267 DOI: 10.1002/dvdy.20309] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In a screen for transcripts differentially expressed during gonadal development in mouse embryos, we identified the novel armadillo-related gene, Alex2. The armadillo (arm) family of proteins share a 42 amino acid tandem repeat motif called the arm domain, through which they interact with different binding partners. These intracellular proteins are implicated in a variety of developmental processes, including cell proliferation, migration, maintenance of tissue integrity, and tumorigenesis. Alex2 is a member of a novel subgroup within the arm family, encoding a protein with a single arm domain and a putative transmembrane or signal sequence. Alex2 has a developmentally regulated expression profile during embryogenesis in the mouse. In the urogenital system, it is strongly expressed in the developing testis but is down-regulated during ovarian development. Alex2 expression is localized within the interstitial cell lineage of the developing testis, which gives rise to peritubular myoid, endothelial, and fetal Leydig cells. Alex2 is also expressed in the developing forebrain and somites and in dorsal root ganglia. In testicular cell lines, Alex2 fusion proteins localize to membrane structures within the cell. The expression profile of Alex2 suggests that it plays a role in the development of several tissues during embryogenesis, notably testicular differentiation. In the developing testis, its expression profile suggests that Alex2 has a role in specification or development of the interstitial cell lineage.
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Affiliation(s)
- Craig A Smith
- Murdoch Childrens Research Institute and Department of Paediatrics, The University of Melbourne, Melbourne, Victoria 3052, Australia.
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169
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Puglianiello A, Campagnolo L, Farini D, Cipollone D, Russo MA, Siracusa G. Expression and role of PDGF-BB and PDGFR-beta during testis morphogenesis in the mouse embryo. J Cell Sci 2004; 117:1151-60. [PMID: 14996938 DOI: 10.1242/jcs.00981] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role played by PDGF in testis morphogenesis is still incompletely understood. The present study investigates the expression and potential role of platelet-derived growth factor-BB (PDGF-BB) and its receptor, PDGF receptor beta (PDGFR-beta), during mouse testis cord formation, and the possibility that the growth factor may be involved in the migration to the gonad of mesenchymal cells of mesonephric origin. Studies from this laboratory have previously shown that mesenchymal cells that migrate from the mesonephros into the gonad, to form peritubular myoid cells and most of the intertubular cells, can be identified by the presence on their surface of the p75 neurotrophin receptor (p75NTR), and can be isolated to near-purity by immunomagnetic selection with anti-p75NTR antibody. We show here that mesonephric p75NTR(+) cells also bear the PDGFR-beta, and are able to migrate and proliferate in vitro in response to PDGF-BB. PDGF-BB is expressed at higher levels in male than female developing gonads, suggesting a role for this factor in testis development. Such a role is further supported by the observation that addition of PDGF-BB to serum-free medium is sufficient to allow organ-cultured male 11.5 days post-coitum urogenital ridges to form testis cords. Finally, we show that mesonephric cell motility and growth induced by exposure to PDGF-BB involve mitogen-activated protein kinases (MAPK) and phosphatidylinositol-3 kinase (PI3-K) pathways, as MAPK inhibitor U0126 and PI3K inhibitor Ly294002 inhibit migration and proliferation in vitro assays. The present findings support the hypothesis that the PDGF/PDGFR system plays a key role in testis morphogenesis in the mouse embryo.
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Affiliation(s)
- Antonella Puglianiello
- Department of Public Health and Cell Biology, Section Histology and Embryology, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
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170
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Ricci G, Catizone A, Galdieri M. Embryonic mouse testis development: role of platelet derived growth factor (PDGF-BB). J Cell Physiol 2004; 200:458-67. [PMID: 15254974 DOI: 10.1002/jcp.20035] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Platelet-derived growth factors (PDGFs) are paracrine growth factors mediating epithelial-mesenchymal interactions and exerting multiple biological activities which include cell proliferation, motility, and differentiation. As previously demonstrated, PDGFs act during embryonic development and recently, by culturing male genital ridges, we have demonstrated that PDGF-BB is able to support in vitro testicular cord formation. In the present paper, we report that PDGF-BB is present during embryonic testis development and, in organ culture, induces cord formation although with reduced diameters compared with the cords formed in the genital ridges cultured in the presence of HGF. Moreover we have analyzed the roles exerted by this growth factor during the morphogenesis of the testis. We demonstrate by immunohistochemical experiments that PDGF-BB and its receptors are synthesized by the male UGRs isolated from 11.5 and 13.5 dpc embryos and by Western blot that the factor is secreted in a biologically active form by testicular cells isolated from 13.5 dpc embryos. The biological roles of the factor have also been studied and we demonstrate that PDGF-BB acts as a migratory factor for male mesonephric cells whose migration is a male specific event necessary for a normal testicular morphogenesis. In addition we demonstrate that during testicular development, PDGF-BB induces testicular cell proliferation being in this way responsible for the increase in size of the testis. Finally we demonstrate that PDGF-BB is able to reorganize dissociated testicular cells inducing the formation of large cellular aggregates. However the structures formed in vitro under PDGF-BB stimulation never had a cord-like morphology similar to the cord-like structures formed in the presence of HGF (Ricci et al., 2002, Mech Dev 118:19-28), suggesting that this factor does not act as a morphogenetic factor during testicular development. All together the data presented in this paper demonstrate that PDGF-BB and its receptors (alpha- and beta-subunits) are present during the crucial ages of embryonic mouse testis morphogenesis and indicate the multiple roles exerted by this factor during the development of the male gonad.
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Affiliation(s)
- G Ricci
- Department of Experimental Medicine, Histology and Embryology Laboratory, School of Medicine, Second University of Naples, Naples, Italy
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171
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Cui S, Ross A, Stallings N, Parker KL, Capel B, Quaggin SE. Disrupted gonadogenesis and male-to-female sex reversal in Pod1knockout mice. Development 2004; 131:4095-105. [PMID: 15289436 DOI: 10.1242/dev.01266] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Congenital defects in genital and/or gonadal development occur in 1 in 1000 humans, but the molecular basis for these defects in most cases remains undefined. We show that the basic helix-loop-helix transcription factor Pod1(capsulin/epicardin/Tcf21) is essential for normal development of the testes and ovaries, and hence for sexual differentiation. The gonads of Pod1knockout (KO) mice were markedly hypoplastic, and the urogenital tracts of both XX and XY mice remained indistinguishable throughout embryogenesis. Within Pod1 KO gonads, the number of cells expressing the cholesterol side-chain cleavage enzyme (Scc) was increased markedly. Biochemical and genetic approaches demonstrated that Pod1 transcriptionally represses steroidogenic factor 1 (Sf1/Nr5a1/Ad4BP), an orphan nuclear receptor that regulates the expression of multiple genes (including Scc) that mediate sexual differentiation. Our results establish that Pod1 is essential for gonadal development, and place it in a transcriptional network that orchestrates cell fate decisions in gonadal progenitors.
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Affiliation(s)
- Shiying Cui
- Department of Maternal and Fetal Health, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Ontario M5G 1X5, Canada
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172
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Schmahl J, Kim Y, Colvin JS, Ornitz DM, Capel B. Fgf9induces proliferation and nuclear localization of FGFR2 in Sertoli precursors during male sex determination. Development 2004; 131:3627-36. [PMID: 15229180 DOI: 10.1242/dev.01239] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recently, we demonstrated that loss of Fgf9 results in a block of testis development and a male to female sex-reversed phenotype; however, the function of Fgf9 in sex determination was unknown. We now show that Fgf9 is necessary for two steps of testis development just downstream of the male sex-determining gene, Sry: (1) for the proliferation of a population of cells that give rise to Sertoli progenitors; and (2) for the nuclear localization of an FGF receptor (FGFR2) in Sertoli cell precursors. The nuclear localization of FGFR2 coincides with the initiation of Sry expression and the nuclear localization of SOX9 during the early differentiation of Sertoli cells and the determination of male fate.
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Affiliation(s)
- Jennifer Schmahl
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
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173
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Brennan J, Capel B. One tissue, two fates: molecular genetic events that underlie testis versus ovary development. Nat Rev Genet 2004; 5:509-21. [PMID: 15211353 DOI: 10.1038/nrg1381] [Citation(s) in RCA: 405] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jennifer Brennan
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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174
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Natoli TA, Alberta JA, Bortvin A, Taglienti ME, Menke DB, Loring J, Jaenisch R, Page DC, Housman DE, Kreidberg JA. Wt1 functions in the development of germ cells in addition to somatic cell lineages of the testis. Dev Biol 2004; 268:429-40. [PMID: 15063178 DOI: 10.1016/j.ydbio.2003.12.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2003] [Revised: 12/03/2003] [Accepted: 12/09/2003] [Indexed: 11/16/2022]
Abstract
The Wilms' tumor suppressor gene, Wt1, encodes a transcription factor critical for development of the urogenital system. To identify lineages within the developing urogenital system that have a cell-autonomous requirement for Wt1, chimeric mice were generated from Wt1-null ES cells. Males with large contributions of Wt1-/- cells showed hypoplastic and dysgenic testes, with seminiferous tubules lacking spermatogonia. Wt1-null cells contributed poorly to both somatic and germ cell lineages within the developing gonad, suggesting an unexpected role for Wt1 in germ cell development in addition to a role in the development of the somatic lineages of the gonad. Wt1 expression was detected in embryonic germ cells beginning at embryonic day 11.5 after migrating primordial germ cells (PGCs) have entered the gonad. Germ cells isolated from Wt1-null embryos showed impaired growth in culture, further demonstrating a role for Wt1 in germ cell proliferation or survival. Therefore, Wt1 plays important, and in some cases previously unrecognized, roles in multiple lineages during urogenital development.
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Affiliation(s)
- Thomas A Natoli
- Department of Medicine, The Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
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175
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Boyer A, Lussier JG, Sinclair AH, McClive PJ, Silversides DW. Pre-sertoli specific gene expression profiling reveals differential expression of Ppt1 and Brd3 genes within the mouse genital ridge at the time of sex determination. Biol Reprod 2004; 71:820-7. [PMID: 15128596 DOI: 10.1095/biolreprod.104.029371] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In mammals, testis determination is initiated when the SRY gene is expressed in pre-Sertoli cells of the undifferentiated genital ridge. SRY directs the differentiation of these cells into Sertoli cells and initiates the testis differentiation pathway via currently ill-defined mechanisms. Because Sertoli cells are the first somatic cells to differentiate within the developing testis, it is likely that the signals for orchestrating testis determination are expressed within pre-Sertoli cells. We have previously generated a transgenic mouse line that expresses green fluorescent protein under the control of the pig SRY promoter, thus marking pre-Sertoli cells via fluorescence. We have now used suppression-subtractive hybridization (SSH) to construct a normalized cDNA library derived from fluorescence-activated cell sorting (FACS) purified pre-Sertoli cells taken from 12.0 to 12.5 days postcoitum (dpc) fetal transgenic mouse testes. A total of 35 candidate cDNAs for known genes were identified. Detection of Sf1, a gene known for its role in sex determination as well as Vanin-1, Vcp1, Sparc, and Aldh3a1, four genes previously identified in differential screens as gene overexpressed in developing testis compared with ovary, support the biological validity of our experimental model. Whole-mount in situ hybridization was performed on the 35 candidate genes for qualitative differential expression between male and female genital ridges; six were upregulated in the testis and one was upregulated in the ovary. The expression pattern of two genes, Ppt1 and Brd3, were examined in further detail. We conclude that combining transgenically marked fluorescent cell populations with differential expression screening is useful for cell expression profiling in developmental systems such as sex determination and differentiation.
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Affiliation(s)
- Alexandre Boyer
- Centre de recherche en reproduction animale, Faculté de médecin vétérinaire, Université de Montréal, St.-Hyacinthe, Québec J2S 7C6, Canada
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176
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Li H, Kim KH. Retinoic Acid Inhibits Rat XY Gonad Development by Blocking Mesonephric Cell Migration and Decreasing the Number of Gonocytes. Biol Reprod 2004; 70:687-93. [PMID: 14613895 DOI: 10.1095/biolreprod.103.023135] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Vitamin A (also called retinol) and its derivatives, retinoic acids (RAs), are required for postnatal testicular function. Abnormal spermatogenesis is observed in rodents on vitamin A-deficient diets and in retinoic acid receptor alpha (RARalpha) knockout mice. In contrast, RA has an inhibitory effect on the XY gonad development in embryos. To characterize this inhibitory effect of RA, we investigated the cellular events that are required for the XY gonad development, including cell migration from the adjacent mesonephros into the gonad, fetal Sertoli cell differentiation, and survival of gonocytes. In organ cultures of Embryonic Day 13 (E13) XY gonads from rats, all-trans-retinoic acid (tRA) inhibited mesonephric cell migration into the gonad. Moreover, treatment with tRA decreased the expression of Müllerian-inhibiting substance in Sertoli cells and dramatically reduced the number of gonocytes. Increased apoptosis was detected in the XY gonads cultured with tRA, suggesting that the loss of gonocytes could be due to increased apoptosis. In addition, Am580, a synthetic compound that exhibits RARalpha-specific agonistic properties, mimicked the inhibitory effects of tRA on the XY gonad development including mesonephric cell migration and gonocyte survival. Conversely, a RARalpha-selective antagonist, Ro 41-5253, suppressed the inhibitory ability of tRA on the XY gonad development. These results suggest that retinoic acid acting through RARalpha negatively affects fetal Sertoli cell differentiation and gonocyte survival and blocks the migration of mesonephric cells, thereby leading to inhibition of the XY gonad development.
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Affiliation(s)
- Hui Li
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, 99164-4234, USA
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177
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Li Y, Yue L, Taketo T, Lau YFC. Protein transduction as a strategy for evaluating important factors in mammalian sex determination and differentiation. Cytogenet Genome Res 2003; 101:237-41. [PMID: 14684989 DOI: 10.1159/000074343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2003] [Accepted: 07/28/2003] [Indexed: 11/19/2022] Open
Abstract
Protein transduction is a powerful tool to deliver biologically active protein into mammalian cells and whole animals. Transduced proteins are folded properly and can mediate their respective functions in their hosts. To examine the feasibility of applying this strategy to study the molecular events of gonadogenesis, we have studied the kinetics of protein transduction and stability of transduced protein in in vitro mouse gonad culture systems using two reporter proteins, TAT-beta-gal and beta-gal fusion proteins with and without the TAT protein transduction domain (PTD) respectively. Our results indicate that the TAT-PTD was critical and essential for protein transduction to cultured fetal gonads. The TAT-beta-gal reporter entered the cells of the gonads and mesonephros efficiently for both sexes at E11.5 to E15.5 stages examined. The delivered protein persisted in the gonads for an extended period after an initial one-hour transduction. The distribution of the reporter was relatively even in gonads and mesonephros at E11.5 stage for both sexes and at later stages in female. The transduced protein was distributed heterogeneously in male gonads after seminiferous tubule differentiation in which the amount of reporter protein was higher outside than inside the tubules. Nevertheless, we surmise that such protein delivery technique should be useful in studies designed to evaluate the sex determining or differentiating functions of various new protein factors identified by advanced differential screening strategies.
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Affiliation(s)
- Y Li
- Department of Medicine, VA Medical Center, University of California, San Francisco, San Francisco, CA 94121, USA
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178
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Beverdam A, Wilhelm D, Koopman P. Molecular characterization of three gonad cell lines. Cytogenet Genome Res 2003; 101:242-9. [PMID: 14684990 DOI: 10.1159/000074344] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Accepted: 09/10/2003] [Indexed: 11/19/2022] Open
Abstract
To facilitate the study of the regulation and downstream interactions of genes involved in gonad development it is important to have a suitable cell culture model. We therefore aimed to characterize molecularly three different mouse gonad cell lines. TM3 and TM4 cells were originally isolated from prepubertal mouse gonads and were tentatively identified as being of Leydig cell and Sertoli cell origin, respectively, based upon their morphology and hormonal responses. The third line is a conditionally immortalized cell line, derived from 10.5-11.5 days post-coitum (dpc) male gonads of transgenic embryos carrying a temperature-sensitive SV40 large T-antigen. We studied by reverse transcription-polymerase chain reaction (RT-PCR) the expression profiles of a number of genes known to be important for early gonad development. Moreover, we assessed these cell lines for their capacity to induce SOX9 transcription upon expression of SRY, a key molecular event occurring during sex determination. We found that all three cell lines were unable to upregulate SOX9 expression upon transfection of SRY-expression constructs, even though these cells express many of the studied embryonic gonad genes. These observations point to a requirement for SRY cofactors for direct or indirect upregulation of SOX9 expression during testis determination.
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Affiliation(s)
- A Beverdam
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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179
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Knower KC, Kelly S, Harley VR. Turning on the male – SRY, SOX9 and sex determination in mammals. Cytogenet Genome Res 2003; 101:185-98. [PMID: 14684982 DOI: 10.1159/000074336] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2003] [Accepted: 07/02/2003] [Indexed: 11/19/2022] Open
Abstract
The decision of the bi-potential gonad to develop into either a testis or ovary is determined by the presence or absence of the Sex-determining Region gene on the Y chromosome (SRY). Since its discovery, almost 13 years ago, the molecular role that SRY plays in initiating the male sexual development cascade has proven difficult to ascertain. While biochemical studies of clinical mutants and mouse genetic models have helped in our understanding of SRY function, no direct downstream targets of SRY have yet been identified. There are, however, a number of other genes of equal importance in determining sexual phenotype, expressed before and after expression of SRY. Of these, one has proven of central importance to mammals and vertebrates, SOX9. This review describes our current knowledge of SRY and SOX9 structure and function in the light of recent key developments.
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Affiliation(s)
- K C Knower
- Human Molecular Genetics Laboratory, Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia
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180
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Abstract
Migration of mesonephric cells into XY gonads is a critical early event in testis cord formation. Based on the fact that anti-Müllerian hormone (AMH) can induce testis cord formation in XX gonads, we investigated whether AMH plays a role in the induction of cell migration. Addition of recombinant AMH induced mesonephric migration into XX gonads in culture. AMH-treated XX gonads displayed increased vascular development and altered morphology of the coelomic epithelium, both features of normal testis differentiation. AMH did not induce markers of Sertoli or Leydig cell differentiation. We examined early testis development in Amh-deficient mice, but found no abnormalities, suggesting that any function AMH may have in vivo is redundant. Other transforming growth factor (TGF-beta) family proteins, bone morphogenetic proteins (BMP2 and BMP4) show similar inductive effects on XX gonads in culture. Although neither BMP2 nor BMP4 is expressed in embryonic XY gonads, our findings suggest that a TGF-beta signalling pathway endogenous to the XY gonad may be involved in regulation of mesonephric cell migration. The factors involved in this process remain to be identified.
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Affiliation(s)
- Andrea J. Ross
- Department of Cell Biology, Duke University Medical Center, Box 3709, 340 Nanaline Duke, Research Dr., Durham, NC 27710, USA
| | - Christopher Tilman
- Department of Cell Biology, Duke University Medical Center, Box 3709, 340 Nanaline Duke, Research Dr., Durham, NC 27710, USA
| | - Humphrey Yao
- Department of Cell Biology, Duke University Medical Center, Box 3709, 340 Nanaline Duke, Research Dr., Durham, NC 27710, USA
| | - David MacLaughlin
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Blanche Capel
- Department of Cell Biology, Duke University Medical Center, Box 3709, 340 Nanaline Duke, Research Dr., Durham, NC 27710, USA
- Corresponding author. Tel.: +1-919-684-6390; fax: +1-919-684-5481. (B. Capel)
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181
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Funes S, Hedrick JA, Vassileva G, Markowitz L, Abbondanzo S, Golovko A, Yang S, Monsma FJ, Gustafson EL. The KiSS-1 receptor GPR54 is essential for the development of the murine reproductive system. Biochem Biophys Res Commun 2003; 312:1357-63. [PMID: 14652023 DOI: 10.1016/j.bbrc.2003.11.066] [Citation(s) in RCA: 475] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
GPR54 is a G-protein-coupled receptor that displays a high percentage of identity in the transmembrane domains with the galanin receptors. The ligand for GPR54 has been identified as a peptide derived from the KiSS-1 gene. KiSS-1 has been shown to have anti-metastatic effects, suggesting that KiSS-1 or its receptor represents a potential therapeutic target. To further our understanding of the physiological function of this receptor, we have generated a mutant mouse line with a targeted disruption of the GPR54 receptor (GPR54 -/-). The analysis of the GPR54 mutant mice revealed developmental abnormalities of both male and female genitalia and histopathological changes in tissues which normally contain sexually dimorphic features. These data suggest a role for GPR54/KiSS-1 in normal sexual development, and indicate that study of the GPR54 mutant mice may provide valuable insights into human reproductive syndromes.
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Affiliation(s)
- Sandrine Funes
- Functional Genomics Research, Discovery Technologies Department, Schering-Plough Research Institute, 2015 Galloping Hill Rd., Kenilworth, NJ 07033, USA
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182
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McClive PJ, Hurley TM, Sarraj MA, van den Bergen JA, Sinclair AH. Subtractive hybridisation screen identifies sexually dimorphic gene expression in the embryonic mouse gonad. Genesis 2003; 37:84-90. [PMID: 14595844 DOI: 10.1002/gene.10231] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The sex of most mammals is determined by the action of SRY. Its presence initiates testis formation resulting in male differentiation, its absence results in ovary formation and female differentiation. We have used suppression subtraction hybridisation between 12.0-12.5 days postcoitum (dpc) mouse testes and ovaries to identify genes that potentially lie within the Sry pathway. Normalised urogenital ridge libraries comprising 8,352 clones were differentially screened with subtracted probes. A total of 272 candidate cDNAs were tested for qualitative differential expression and localisation by whole mount in situ hybridisation; germ cell-dependent or -independent expression was further resolved using busulfan. Fifty-four genes were identified that showed higher expression in the testis than the ovary. One novel gene may be a candidate for interactions with WT1, based on its localisation to Sertoli cells and map position (16q24.3).
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183
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Yao HHC, DiNapoli L, Capel B. Meiotic germ cells antagonize mesonephric cell migration and testis cord formation in mouse gonads. Development 2003; 130:5895-902. [PMID: 14561636 PMCID: PMC4073601 DOI: 10.1242/dev.00836] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The developmental fate of primordial germ cells in the mammalian gonad depends on their environment. In the XY gonad, Sry induces a cascade of molecular and cellular events leading to the organization of testis cords. Germ cells are sequestered inside testis cords by 12.5 dpc where they arrest in mitosis. If the testis pathway is not initiated, germ cells spontaneously enter meiosis by 13.5 dpc, and the gonad follows the ovarian fate. We have previously shown that some testis-specific events, such as mesonephric cell migration, can be experimentally induced into XX gonads prior to 12.5 dpc. However, after that time, XX gonads are resistant to the induction of cell migration. In current experiments, we provide evidence that this effect is dependent on XX germ cells rather than on XX somatic cells. We show that, although mesonephric cell migration cannot be induced into normal XX gonads at 14.5 dpc, it can be induced into XX gonads depleted of germ cells. We also show that when 14.5 dpc XX somatic cells are recombined with XY somatic cells, testis cord structures form normally; however, when XX germ cells are recombined with XY somatic cells, cord structures are disrupted. Sandwich culture experiments suggest that the inhibitory effect of XX germ cells is mediated through short-range interactions rather than through a long-range diffusible factor. The developmental stage at which XX germ cells show a disruptive effect on the male pathway is the stage at which meiosis is normally initiated, based on the immunodetection of meiotic markers. We suggest that at the stage when germ cells commit to meiosis, they reinforce ovarian fate by antagonizing the testis pathway.
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184
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Li H, Kim KH. Effects of ethanol on embryonic and neonatal rat testes in organ cultures. JOURNAL OF ANDROLOGY 2003; 24:653-60. [PMID: 12954654 DOI: 10.1002/j.1939-4640.2003.tb02723.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Ethanol exposure in adult animals and humans has shown to elicit significant inhibitory effects on the function of male reproduction, but consequences of ethanol exposure on the embryonic and early postnatal testis development are not known. The current study investigated the effect of ethanol on embryonic and neonatal testis development using an organ culture technique. In embryonic day 13 (E13) testis organ cultures, ethanol had no effect on the testicular cord formation, the expression of Müllerian-inhibiting substance (MIS) in Sertoli cells or the number of gonocytes. Similarly, in the ethanol-treated embryonic day 18 (E18) testes, both the number of gonocytes and the expression of GATA-4 and MIS were similar to those from the control testes. In contrast, in postnatal day 3 (P3) testes, ethanol at concentrations of 150 and 200 mM significantly decreased the number of gonocytes without affecting the expression of GATA-4 and MIS in Sertoli cells. This effect was shown to be resulting from the enhanced apoptosis of gonocytes. In addition, ethanol abnormally activated retinoic acid receptor alpha (RARalpha), as indicated by increased nuclear localization of RARalpha with increasing doses of ethanol treatment. These observations suggest that the effect of ethanol on testis varies at different stages during embryonic and neonatal testis development. Furthermore, germ cells may be the main target for the action of ethanol on the early postnatal testis.
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Affiliation(s)
- Hui Li
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
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185
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Abstract
DAX1 encoded by NR0B1, when mutated, is responsible for X-linked adrenal hypoplasia congenita (AHC). AHC is due to failure of the adrenal cortex to develop normally and is fatal if untreated. When duplicated, this gene is associated with an XY sex-reversed phenotype. DAX1 expression is present during development of the steroidogenic hypothalamic-pituitary-adrenal-gonadal (HPAG) axis and persists into adult life. Despite recognition of the crucial role for DAX1, its function remains largely undefined. The phenotypes of patients and animal models are complex and not always in agreement. Investigations using cell lines have proved difficult to interpret, possibly reflecting cell line choices and their limited characterization. We will review the efforts of our group and others to identify appropriate cell lines for optimizing ex vivo analysis of NR0B1 function throughout development. We will examine the role of DAX1 and its network partners in development of the hypothalamic-pituitary-adrenal/gonadal axis (HPAG) using a variety of different types of investigations, including those in model organisms. This network analysis will help us to understand normal and abnormal development of the HPAG. In addition, these studies permit identification of candidate genes for human inborn errors of HPAG development.
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186
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Smith L, Van Hateren N, Willan J, Romero R, Blanco G, Siggers P, Walsh J, Banerjee R, Denny P, Ponting C, Greenfield A. Candidate testis-determining gene, Maestro (Mro), encodes a novel HEAT repeat protein. Dev Dyn 2003; 227:600-7. [PMID: 12889070 DOI: 10.1002/dvdy.10342] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mammalian sex determination depends on the presence or absence of SRY transcripts in the embryonic gonad. Expression of SRY initiates a pathway of gene expression resulting in testis development. Here, we describe a novel gene potentially functioning in this pathway using a cDNA microarray screen for genes exhibiting sexually dimorphic expression during murine gonad development. Maestro (Mro) transcripts are first detected in the developing male gonad before overt testis differentiation. By 12.5 days postcoitus (dpc), Mro transcription is restricted to the developing testis cords and its expression is not germ cell-dependent. No expression is observed in female gonads between 10.5 and 14.5 dpc. Maestro encodes a protein containing HEAT-like repeats that localizes to the nucleolus in cell transfection assays. Maestro maps to a region of mouse chromosome 18 containing a genetic modifier of XX sex reversal. We discuss the possible function of Maestro in light of these data.
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Affiliation(s)
- Lee Smith
- MRC Mammalian Genetics Unit, Harwell, Didcot, United Kingdom
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187
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Jeays-Ward K, Hoyle C, Brennan J, Dandonneau M, Alldus G, Capel B, Swain A. Endothelial and steroidogenic cell migration are regulated by WNT4 in the developing mammalian gonad. Development 2003; 130:3663-70. [PMID: 12835383 DOI: 10.1242/dev.00591] [Citation(s) in RCA: 247] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The signalling molecule WNT4 has been associated with sex reversal phenotypes in mammals. Here we show that the role of WNT4 in gonad development is to pattern the sex-specific vasculature and to regulate steroidogenic cell recruitment. Vascular formation and steroid production in the mammalian gonad occur in a sex-specific manner. During testis development, endothelial cells migrate from the mesonephros into the gonad to form a coelomic blood vessel. Leydig cells differentiate and produce steroid hormones a day later. Neither of these events occurs in the XX gonad. We show that WNT4 represses mesonephric endothelial and steroidogenic cell migration in the XX gonad, preventing the formation of a male-specific coelomic blood vessel and the production of steroids. In the XY gonad, Wnt4 expression is downregulated after sex determination. Transgenic misexpression of Wnt4 in the embryonic testis did not inhibit coelomic vessel formation but vascular pattern was affected. Leydig cell differentiation was not affected in these transgenic animals and our data implies that Wnt4 does not regulate steroidogenic cell differentiation but represses the migration of steroidogenic adrenal precursors into the gonad. These studies provide a model for understanding how the same signalling molecule can act on two different cell types to coordinate sex development.
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Affiliation(s)
- Katherine Jeays-Ward
- Section of Gene Function and Regulation, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
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188
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Abstract
Cell proliferation has been shown to have multiple functions in development and pattern formation, including roles in growth, morphogenesis, and gene expression. Previously, we determined that the earliest known morphological event downstream of the male sex determining gene, Sry, is the induction of proliferation. In this study, we used proliferation inhibitors to block cell division during early gonad development, at stages before the XY gonad has committed to the testis pathway. Using the expression of sex-specific genes and the formation of testis morphology as markers of testis determination, we found that proliferation within a specific 8-h window was critical for the establishment of the male pathway and the formation of the testis. Inhibition of proliferation before or after this critical period led to smaller gonads, but did not block testis formation. The critical period of proliferation coincides with the initiation of Sry expression and is essential for the differentiation of Sertoli cells, suggesting that proliferation is a vital component of the initiation of the male pathway by Sry. We believe these studies suggest that proliferation is involved not only in the elaboration of organ pattern, but also in the choice between patterns (male and female) in the bipotential gonad.
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Affiliation(s)
- Jennifer Schmahl
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
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189
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Cupp AS, Uzumcu M, Skinner MK. Chemotactic role of neurotropin 3 in the embryonic testis that facilitates male sex determination. Biol Reprod 2003; 68:2033-7. [PMID: 12606390 DOI: 10.1095/biolreprod.102.012617] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The first morphological event after initiation of male sex determination is seminiferous cord formation in the embryonic testis. Cord formation requires migration of pre-peritubular myoid cells from the adjacent mesonephros. The embryonic Sertoli cells are the first testicular cells to differentiate and have been shown to express neurotropin-3 (NT3), which can act on high-affinity trkC receptors expressed on migrating mesonephros cells. NT3 expression is elevated in the embryonic testis during the time of seminiferous cord formation. A trkC receptor tyrophostin inhibitor, AG879, was found to inhibit seminiferous cord formation and mesonephros cell migration. Beads containing NT3 were found to directly promote mesonephros cell migration into the gonad. Beads containing other growth factors such as epidermal growth factor (EGF) did not influence cell migration. At male sex determination the SRY gene promotes testis development and the expression of downstream sex differentiation genes such as SOX-9. Inhibition of NT3 actions caused a reduction in the expression of SOX-9. Combined observations suggest that when male sex determination is initiated, the developing Sertoli cells express NT3 as a chemotactic agent for migrating mesonephros cells, which are essential to promote embryonic testis cord formation and influence downstream male sex differentiation.
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Affiliation(s)
- Andrea S Cupp
- Center for Reproductive Biology, School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-4231, USA
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190
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Wakayama T, Hamada K, Yamamoto M, Suda T, Iseki S. The expression of platelet endothelial cell adhesion molecule-1 in mouse primordial germ cells during their migration and early gonadal formation. Histochem Cell Biol 2003; 119:355-62. [PMID: 12736726 DOI: 10.1007/s00418-003-0528-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2003] [Indexed: 10/25/2022]
Abstract
The platelet endothelial cell adhesion molecule-1 (PECAM-1), or CD31, a member of the immunoglobulin superfamily, is located on the plasma membrane of endothelial and hematopoietic cells and involved in vascular development and inflammation. In this study, by use of immunohistochemistry at light and electron microscopic levels in combination with enzyme histochemistry for alkaline phosphatase, we demonstrated that PECAM-1/CD31 is expressed in the mouse primordial germ cell (PGC). Up to 8 days postcoitum (dpc), PGCs with alkaline phosphatase activity showed no PECAM-1/CD31 immunoreactivity. At 9 dpc, PECAM-1/CD31 immunoreactivity was first detected with low intensity in some PGCs located in the hindgut. Between 10 and 11 dpc, intense immunoreactivity was shown on the entire surface of PGCs migrating along the dorsal wall. After arrival and settlement of PGCs in the genital ridges around 11.5 dpc, the intense immunoreactivity was maintained on the entire surface of PGCs. By electron microscopy, the immunoreactivity was localized exclusively on the plasma membrane of PGCs, being as strong at the portions adjacent to neighboring PGCs as those adjacent to somatic cells. As the male and female gonads began to differentiate, PECAM-1/CD31 immunoreactivity remained strong in germ cells until 13 dpc, after which it gradually decreased in intensity and disappeared by 16 dpc. These results suggested that cell-to-cell interaction through PECAM-1/CD31 plays roles in the development of PGCs during their migration on the dorsal wall and homing in the gonads.
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Affiliation(s)
- Tomohiko Wakayama
- Department of Histology and Embryology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, 920-8640 Kanazawa, Japan
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191
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McClive PJ, Sinclair AH. Type II and type IX collagen transcript isoforms are expressed during mouse testis development. Biol Reprod 2003; 68:1742-7. [PMID: 12606408 DOI: 10.1095/biolreprod.102.008235] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mutations in the transcription factor SOX9 give rise to campomelic dysplasia, a syndrome characterized by skeletal abnormalities and XY sex reversal. Sox9 is expressed at sites of chondrogenesis and in the developing testis, and, thus, it plays a role in two overtly different pathways of differentiation. Previous studies have identified the gene for type II collagen, Col2a1, as a target of Sox9 in mouse chondrocytes and implicated Col9a3 as a Sox9 target in testis. Using differential expression analysis combined with reverse transcription-polymerase chain reaction and whole-mount in situ hybridization, we have identified nonchondrocytic collagen transcript isoforms that are expressed in the early male mouse gonad. Male-specific, gonadal expression of nonchondrocytic Col2a1 was first seen at 11.5 days postcoitum (dpc) and was undetectable by 13.5 dpc. This was accompanied by increasing expression of nonchondrocytic Col9a1, Col9a2, and Col9a3, first detected at 11.5 dpc. Expression was analyzed in testes that had been depleted of germ cells by the cytotoxic drug busulfan. These studies showed Col9a3 and Col2a1 to be expressed in Sertoli cells within the developing testis cords. Nonchondrocytic type II collagen contains a cysteine-rich domain that has been shown to bind members of the transforming growth factor beta superfamily of signaling molecules. Thus, this interaction may play a role in the morphogenesis and differentiation of the testis.
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Affiliation(s)
- Peter J McClive
- Murdoch Children's Research Institute and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Victoria 3052, Australia.
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192
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Schmahl J, Yao HH, Pierucci-Alves F, Capel B. Colocalization of WT1 and cell proliferation reveals conserved mechanisms in temperature-dependent sex determination. Genesis 2003; 35:193-201. [PMID: 12717730 PMCID: PMC4041374 DOI: 10.1002/gene.10176] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
During vertebrate development the gonad has two possible fates, the testis or the ovary. The choice between these fates is made by a variety of sex-determining mechanisms, from the sex-determining gene on the Y chromosome (Sry) in mammals, to nongenetic temperature-dependent systems in many reptiles. Despite the differences in the mechanisms at the top of the sex-determining cascade, the resulting morphology and many genes involved in early testis and ovarian development are common to most vertebrates, leading to the hypothesis that the underlying processes of sex determination are conserved. In this study, we examined the early steps of gonad development in the red-eared slider turtle (Trachemys scripta), a species that uses the temperature of egg incubation to determine sex. A dramatic increase in cell proliferation was observed in the male gonad during the earliest stages of sex determination. Using the localization of Wilms' Tumor suppressor 1 (WT1), we determined that this proliferation increase occurred in a population that contained pre-Sertoli cells. The proliferation of pre-Sertoli cells has been documented during sex determination in both mice and alligators, suggesting that proliferation of this cell type has an important role in vertebrate testis organogenesis and the determination of male fate.
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Affiliation(s)
| | | | | | - Blanche Capel
- Correspondence to: Blanche Capel, Box 3709 Duke University Medical Center, Durham NC, 27710.
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193
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Brennan J, Tilmann C, Capel B. Pdgfr-alpha mediates testis cord organization and fetal Leydig cell development in the XY gonad. Genes Dev 2003; 17:800-10. [PMID: 12651897 PMCID: PMC196020 DOI: 10.1101/gad.1052503] [Citation(s) in RCA: 260] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
During testis development, the rapid morphological changes initiated by Sry require the coordinate integration of many signaling pathways. Based on the established role of the platelet-derived growth factor (PDGF) family of ligands and receptors in migration, proliferation, and differentiation of cells in various organ systems, we have investigated the role of PDGF in testis organogenesis. Analysis of expression patterns and characterization of the gonad phenotype in Pdgfr-alpha(-/-) embryos identified PDGFR-alpha as a critical mediator of signaling in the early testis at multiple steps of testis development. Pdgfr-alpha(-/-) XY gonads displayed disruptions in the organization of the vasculature and in the partitioning of interstitial and testis cord compartments. Closer examination revealed severe reductions in characteristic XY proliferation, mesonephric cell migration, and fetal Leydig cell differentiation. This work identifies PDGF signaling through the alpha receptor as an important event downstream of Sry in testis organogenesis and Leydig cell differentiation.
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Affiliation(s)
- Jennifer Brennan
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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194
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Meeks JJ, Crawford SE, Russell TA, Morohashi KI, Weiss J, Jameson JL. Dax1 regulates testis cord organization during gonadal differentiation. Development 2003; 130:1029-36. [PMID: 12538527 DOI: 10.1242/dev.00316] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutations of the DAX1 nuclear receptor gene cause adrenal hypoplasia congenita, an X-linked disorder characterized by adrenal insufficiency and hypogonadotropic hypogonadism. Targeted deletion of Dax1 in mice also reveals primary testicular dysgenesis, which is manifest by obstruction of the rete testis by Sertoli cells and hyperplastic Leydig cells, leading to seminiferous tubule dilation and degeneration of germ cells. Because Dax1 is expressed early in gonadal development, and because Sertoli and Leydig cells are located ectopically in the adult, we hypothesized that these testis abnormalities are the result of an early defect in testis development. In Dax1(-/Y) males, the gonad develops normally until 12.5 dpc. However, by 13.5 dpc, the testis cords are disorganized and incompletely formed in Dax1-deficient mice. The number of germ and Sertoli cells is unchanged, and the expression of Sertoli-specific markers appears to be normal. However, the number of peritubular myoid cells, which normally surround the testis cords, is reduced. BrdU labeling of peritubular myoid cells is low, consistent with decreased proliferation. The basal lamina produced by peritubular myoid and Sertoli cells is disrupted, leading to open and incompletely formed testis cords. Leydig cells, which normally reside in the peritubular space and extend from the coelomic surface to the dorsal surface of the gonad, are restricted to the coelomic surface of Dax1-deficient testis. We conclude that Dax1 plays a crucial role in testis differentiation by regulating the development of peritubular myoid cells and the formation of intact testis cords. The developmental abnormalities in the Dax1-deficient testis lay the foundation for gonadal dysgenesis and infertility in adult mice and, potentially in humans with DAX1 mutations.
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Affiliation(s)
- Joshua J Meeks
- Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
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195
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Uzumcu M, Westfall SD, Dirks KA, Skinner MK. Embryonic testis cord formation and mesonephric cell migration requires the phosphotidylinositol 3-kinase signaling pathway. Biol Reprod 2002; 67:1927-35. [PMID: 12444071 DOI: 10.1095/biolreprod.102.006254] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Mesonephric cell migration and seminiferous cord formation are critical processes in embryonic testis development at the time of male sex determination. Extracellular growth factors shown to influence seminiferous cord formation such as neurotropin-3 utilize in part the phosphotidylinositol 3-kinase (PI3K) signal transduction pathway. The current study investigates the hypothesis that the PI3K pathway is critical in seminiferous cord formation and testis development. The role of the PI3K signaling pathway in testicular cord formation was examined using an Embryonic Day 13 organ culture system and a PI3K-specific inhibitor LY294002. The actions of a mitogen-activated protein (MAP) kinase-specific inhibitor PD98059 was also examined. The PI3K inhibitor blocked cord formation or reduced the number of cords in a concentration-dependent manner. The actions of LY294002 were found to have a developmental stage specificity in that cord inhibition was observed in organs from embryos with 16-17 tail somites, while organs from embryos with 19 or more tail somites had no block in cord formation and only a small reduction in cord number. In contrast, the MAP kinase inhibitor PD98059 did not block cord formation and only caused a slight reduction in cord number. Neither PI3K or MAP kinase inhibitor altered apoptotic cell number, suggesting apoptosis was not the reason for the inhibition of cord formation. Embryonic testis cell migration assays showed that the PI3K inhibitor LY294002 blocked mesonephros cell migration into the testis, while the MAP kinase inhibitor had no effect. Observations suggest the interference of cell migration is the cause for the inhibition of cord formation. Western blot analysis confirmed that LY294002 and PD98509 inhibited phosphorylation of Akt and ERK1/ERK2, respectively. Combined observations demonstrate that the PI3K signaling pathway is involved in embryonic testis cord formation and mesonephros cell migration.
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Affiliation(s)
- Mehmet Uzumcu
- Center for Reproductive Biology, School of Molecular Biosciences, Washington State University, Pullman 99164-4231, USA
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196
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Tevosian SG, Albrecht KH, Crispino JD, Fujiwara Y, Eicher EM, Orkin SH. Gonadal differentiation, sex determination and normalSryexpression in mice require direct interaction between transcription partners GATA4 and FOG2. Development 2002; 129:4627-34. [PMID: 12223418 DOI: 10.1242/dev.129.19.4627] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In mammals, Sry expression in the bipotential, undifferentiated gonad directs the support cell precursors to differentiate as Sertoli cells, thus initiating the testis differentiation pathway. In the absence of Sry, or if Sry is expressed at insufficient levels, the support cell precursors differentiate as granulosa cells, thus initiating the ovarian pathway. The molecular mechanisms upstream and downstream of Sry are not well understood. We demonstrate that the transcription factor GATA4 and its co-factor FOG2 are required for gonadal differentiation. Mouse fetuses homozygous for a null allele of Fog2 or homozygous for a targeted mutation in Gata4 (Gata4ki) that abrogates the interaction of GATA4 with FOG co-factors exhibit abnormalities in gonadogenesis. We found that Sry transcript levels were significantly reduced in XY Fog2–/– gonads at E11.5, which is the time when Sry expression normally reaches its peak. In addition, three genes crucial for normal Sertoli cell function (Sox9, Mis and Dhh) and three Leydig cell steroid biosynthetic enzymes (p450scc, 3βHSD and p450c17) were not expressed in XY Fog2–/– and Gataki/ki gonads, whereas Wnt4, a gene required for normal ovarian development, was expressed ectopically. By contrast, Wt1 and Sf1, which are expressed prior to Sry and necessary for gonad development in both sexes, were expressed normally in both types of mutant XY gonads. These results indicate that GATA4 and FOG2 and their physical interaction are required for normal gonadal development.
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Affiliation(s)
- Sergei G Tevosian
- Division of Hematology and Oncology, Children's Hospital, Harvard Medical School, Boston, MA, USA
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197
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Ricci G, Catizone A, Galdieri M. Pleiotropic activity of hepatocyte growth factor during embryonic mouse testis development. Mech Dev 2002; 118:19-28. [PMID: 12351166 DOI: 10.1016/s0925-4773(02)00247-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The hepatocyte growth factor (HGF) is a pleiotropic cytokine whose action is mediated by c-met, a glycoproteic receptor with tyrosine kinase activity which transduces its multiple biological activities including cell proliferation, motility and differentiation. During embryonic development HGF acts as a morphogenetic factor as previously demonstrated for metanephric and lung development. Recently, culturing male genital ridges, we demonstrated that HGF is able to support in vitro testicular cord formation. In the present paper we report the expression pattern of the HGF gene during embryonic testis development and the multiple roles exerted by this factor during the morphogenesis of this organ. Northern blot analysis reveals a positive signal in urogenital ridges isolated from 11.5 days post coitum (dpc) embryos and in testes isolated from 13.5 and 15.5 dpc male embryos. On the contrary HGF mRNA is undetectable in ovaries isolated from 13.5 and 15.5 dpc embryos. Moreover, we demonstrate that HGF is synthesized and secreted by the male gonad and is biologically active. These data indicate a male specific biological function of HGF during embryonic gonadal development. This hypothesis is supported by the in vitro demonstration that HGF acts as a migratory factor for male mesonephric cells which is a male specific event. In addition we demonstrate that during testicular development, HGF acts as a morphogenetic factor able to reorganize dissociated testicular cells which, under HGF stimulation, form a tridimensional network of cord-like structures. Finally, we demonstrate that HGF induces testicular cell proliferation in this way being responsible for the size increase of the testis. All together the data presented in this paper demonstrate that HGF is expressed during the embryonic development of the testis and clarify the multiple roles exerted by this factor during the morphogenesis of the male gonad.
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Affiliation(s)
- G Ricci
- Department of Histology and Medical Embryology, University of Rome La Sapienza, Via A. Scarpa 14, Rome 00161, Italy
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198
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Gasca S, Canizares J, De Santa Barbara P, Mejean C, Poulat F, Berta P, Boizet-Bonhoure B. A nuclear export signal within the high mobility group domain regulates the nucleocytoplasmic translocation of SOX9 during sexual determination. Proc Natl Acad Sci U S A 2002; 99:11199-204. [PMID: 12169669 PMCID: PMC123233 DOI: 10.1073/pnas.172383099] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In mammals, male sex determination starts when the Y chromosome Sry gene is expressed within the undetermined male gonad. One of the earliest effect of Sry expression is to induce up-regulation of Sox9 gene expression in the developing gonad. SOX9, like SRY, contains a high mobility group domain and is sufficient to induce testis differentiation in transgenic XX mice. Before sexual differentiation, SOX9 protein is initially found in the cytoplasm of undifferentiated gonads from both sexes. At the time of testis differentiation and anti-Müllerian hormone expression, it becomes localized to the nuclear compartment in males whereas it is down-regulated in females. In this report, we used NIH 3T3 cells as a model to examine the regulation of SOX9 nucleo-cytoplasmic shuttling. SOX9-transfected cells expressed nuclear and cytoplasmic SOX9 whereas transfected cells treated with the nuclear export inhibitor leptomycin B, displayed an exclusive nuclear localization of SOX9. By using SOX9 deletion constructs in green fluorescent protein fusion proteins, we identified a functional nuclear export signal sequence between amino acids 134 and 147 of SOX9 high mobility group box. More strikingly, we show that inhibiting nuclear export with leptomycin B in mouse XX gonads cultured in vitro induced a sex reversal phenotype characterized by nuclear SOX9 and anti-Müllerian hormone expression. These results indicate that SOX9 nuclear export signal is essential for SOX9 sex-specific subcellular localization and could be part of a regulatory switch repressing (in females) or triggering (in males) male-specific sexual differentiation.
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Affiliation(s)
- Stephan Gasca
- Human Molecular Genetics Group, Institut de Génétique Humaine, Centre National de la Recherche Scientifique Unité Propre de Recherche 1142, 34396 Montpellier Cedex 5, France
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199
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Yao HHC, Capel B. Disruption of testis cords by cyclopamine or forskolin reveals independent cellular pathways in testis organogenesis. Dev Biol 2002; 246:356-65. [PMID: 12051821 PMCID: PMC4073602 DOI: 10.1006/dbio.2002.0663] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Most studies to date indicate that the formation of testis cords is critical for proper Sertoli cell differentiation, inhibition of germ cell meiosis, and regulation of Leydig cell differentiation. However, the connections between these events are poorly understood. The objective of this study was to dissect the molecular and cellular relationships between these events in testis formation. We took advantage of the different effects of two hedgehog signaling inhibitors, cyclopamine and forskolin, on gonad explant cultures. Both hedgehog inhibitors phenocopied the disruptive effect of Dhh(-/-) on formation of testis cords without influencing Sertoli cell differentiation. However, they exhibited different effects on other cellular events during testis development. Treatment with cyclopamine did not affect inhibition of germ cell meiosis and mesonephric cell migration but caused defects in Leydig cell differentiation. In contrast, forskolin treatment induced germ cell meiosis, inhibited mesonephric cell migration, and had no effect on Leydig cell differentiation. By carefully contrasting the different effects of these two hedgehog inhibitors, we demonstrate that, although formation of testis cords and development of other cell types normally take place in a tightly regulated sequence, each of these events can occur independent of the others.
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Affiliation(s)
- Humphrey Hung-Chang Yao
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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200
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Yao HHC, Whoriskey W, Capel B. Desert Hedgehog/Patched 1 signaling specifies fetal Leydig cell fate in testis organogenesis. Genes Dev 2002; 16:1433-40. [PMID: 12050120 PMCID: PMC186321 DOI: 10.1101/gad.981202] [Citation(s) in RCA: 344] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Establishment of the steroid-producing Leydig cell lineage is an event downstream of Sry that is critical for masculinization of mammalian embryos. Neither the origin of fetal Leydig cell precursors nor the signaling pathway that specifies the Leydig cell lineage is known. Based on the sex-specific expression patterns of Desert Hedgehog (Dhh) and its receptor Patched 1 (Ptch1) in XY gonads, we investigated the potential role of DHH/PTCH1 signaling in the origin and specification of fetal Leydig cells. Analysis of Dhh(-/-) XY gonads revealed that differentiation of fetal Leydig cells was severely defective. Defects in Leydig cell differentiation in Dhh(-/-) XY gonads did not result from failure of cell migration from the mesonephros, thought to be a possible source of Leydig cell precursors. Nor did DHH/PTCH1 signaling appear to be involved in the proliferation or survival of fetal Leydig precursors in the interstitium of the XY gonad. Instead, our results suggest that DHH/PTCH1 signaling triggers Leydig cell differentiation by up-regulating Steroidogenic Factor 1 and P450 Side Chain Cleavage enzyme expression in Ptch1-expressing precursor cells located outside testis cords.
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Affiliation(s)
- Humphrey Hung-Chang Yao
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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