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Usongo M, Farookhi R. β-catenin/Tcf-signaling appears to establish the murine ovarian surface epithelium (OSE) and remains active in selected postnatal OSE cells. BMC DEVELOPMENTAL BIOLOGY 2012; 12:17. [PMID: 22682531 PMCID: PMC3465187 DOI: 10.1186/1471-213x-12-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 03/28/2012] [Indexed: 02/07/2023]
Abstract
Background Wnts are a family of secreted signaling molecules involved in a number of developmental processes including the establishment of cell fate, polarity and proliferation. Recent studies also implicate wnts in epithelial adult stem cell maintenance, renewal and differentiation. Wnts transduce their signal through one of three signaling pathways. The best studied, the wnt/β-catenin pathway, leads to an increase in intracellular β-catenin which acts as a co-transcription factor with members of the Tcf/Lef family. A number of wnts are expressed in the ovary, specifically in the membrana granulosa and ovarian surface epithelium (OSE). We investigated the spatio-temporal pattern of β-catenin/Tcf expression in the OSE using responsive transgenic (TopGal) mice. Results The generated β-galactosidase response (lacZ+) identified the cell population that overlies the medio-lateral surface of the indifferent gonad at embryonic day (E) 11.5. From E12.5 onwards, lacZ expression disappeared in cells covering the testis but remained with ovary development. LacZ+ OSE cells were present throughout embryonic and postnatal ovarian development but demonstrated an age-dependent decrease to a small proportion when animals were weaned and remained at this proportion with aging. Flow cytometric (FACS) and ovarian section analyses showed lacZ+ cells constitute approximately 20% of OSE in postnatal (day 1) mice which fell to 8% in 5 day-old animals while in prepubertal and adult mice this accounted for only 0.2% of OSE. Apoptosis was undetected in OSE of neonates and β-catenin/Tcf-signaling cells were proliferative in neonatal mice indicating that neither cell death nor proliferation failure was responsible for the proportion alteration. It appeared that lacZ+ cells give rise to lacZ- cells and this was confirmed in cell cultures. The DNA-binding dye DyeCycle Violet was used to set up the side population (SP) assay aimed at identifying subpopulations of OSE cells with chemoresistance phenotype associated with ABCG2 transporter activity. FACS analysis revealed lacZ+ cells exhibit cytoprotective mechanisms as indicated by enrichment within the SP. Conclusions The study raises the possibility that wnt/β-catenin-signaling cells constitute a progenitor cell population and could underlie the pronounced histopathology observed for human ovarian cancer.
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Affiliation(s)
- Macalister Usongo
- Department of Experimental Medicine, McGill University, Montreal, QC, Canada
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152
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Molecular control of oogenesis. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1896-912. [PMID: 22634430 DOI: 10.1016/j.bbadis.2012.05.013] [Citation(s) in RCA: 242] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 05/08/2012] [Accepted: 05/13/2012] [Indexed: 11/20/2022]
Abstract
Oogenesis is a complex process regulated by a vast number of intra- and extra-ovarian factors. Oogonia, which originate from primordial germ cells, proliferate by mitosis and form primary oocytes that arrest at the prophase stage of the first meiotic division until they are fully-grown. Within primary oocytes, synthesis and accumulation of RNAs and proteins throughout oogenesis are essential for oocyte growth and maturation; and moreover, crucial for developing into a viable embryo after fertilization. Oocyte meiotic and developmental competence is gained in a gradual and sequential manner during folliculogenesis and is related to the fact that the oocyte grows in interaction with its companion somatic cells. Communication between oocyte and its surrounding granulosa cells is vital, both for oocyte development and for granulosa cells differentiation. Oocytes depend on differentiated cumulus cells, which provide them with nutrients and regulatory signals needed to promote oocyte nuclear and cytoplasmic maturation and consequently the acquisition of developmental competence.The purpose of this article is to summarize recent knowledge on the molecular aspects of oogenesis and oocyte maturation, and the crucial role of cumulus-cell interactions, highlighting the valuable contribution of experimental evidences obtained in animal models. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.
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153
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Ungewitter EK, Yao HHC. How to make a gonad: cellular mechanisms governing formation of the testes and ovaries. Sex Dev 2012; 7:7-20. [PMID: 22614391 PMCID: PMC3474884 DOI: 10.1159/000338612] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Sex determination of the gonad is an extraordinary process by which a single organ anlage is directed to form one of two different structures, a testis or an ovary. Morphogenesis of these two organs utilizes many common cellular events; differences in the timing and execution of these events must combine to generate sexually dimorphic structures. In this chapter, we review recent research on the cellular processes of gonad morphogenesis, focusing on data from mouse models. We highlight the shared cellular mechanisms in testis and ovary morphogenesis and examine the differences that enable formation of the two organs responsible for the perpetuation of all sexually reproducing species.
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Affiliation(s)
- E K Ungewitter
- Reproductive Developmental Biology Group, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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154
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Correa SM, Washburn LL, Kahlon RS, Musson MC, Bouma GJ, Eicher EM, Albrecht KH. Sex reversal in C57BL/6J XY mice caused by increased expression of ovarian genes and insufficient activation of the testis determining pathway. PLoS Genet 2012; 8:e1002569. [PMID: 22496664 PMCID: PMC3320579 DOI: 10.1371/journal.pgen.1002569] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 01/16/2012] [Indexed: 11/18/2022] Open
Abstract
Sex reversal can occur in XY humans with only a single functional WT1 or SF1 allele or a duplication of the chromosome region containing WNT4. In contrast, XY mice with only a single functional Wt1, Sf1, or Wnt4 allele, or mice that over-express Wnt4 from a transgene, reportedly are not sex-reversed. Because genetic background plays a critical role in testis differentiation, particularly in C57BL/6J (B6) mice, we tested the hypothesis that Wt1, Sf1, and Wnt4 are dosage sensitive in B6 XY mice. We found that reduced Wt1 or Sf1 dosage in B6 XY(B6) mice impaired testis differentiation, but no ovarian tissue developed. If, however, a Y(AKR) chromosome replaced the Y(B6) chromosome, these otherwise genetically identical B6 XY mice developed ovarian tissue. In contrast, reduced Wnt4 dosage increased the amount of testicular tissue present in Sf1+/- B6 XY(AKR), Wt1+/- B6 XY(AKR), B6 XY(POS), and B6 XY(AKR) fetuses. We propose that Wt1(B6) and Sf1(B6) are hypomorphic alleles of testis-determining pathway genes and that Wnt4(B6) is a hypermorphic allele of an ovary-determining pathway gene. The latter hypothesis is supported by the finding that expression of Wnt4 and four other genes in the ovary-determining pathway are elevated in normal B6 XX E12.5 ovaries. We propose that B6 mice are sensitive to XY sex reversal, at least in part, because they carry Wt1(B6) and/or Sf1(B6) alleles that compromise testis differentiation and a Wnt4(B6) allele that promotes ovary differentiation and thereby antagonizes testis differentiation. Addition of a "weak" Sry allele, such as the one on the Y(POS) chromosome, to the sensitized B6 background results in inappropriate development of ovarian tissue. We conclude that Wt1, Sf1, and Wnt4 are dosage-sensitive in mice, this dosage-sensitivity is genetic background-dependant, and the mouse strains described here are good models for the investigation of human dosage-sensitive XY sex reversal.
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Affiliation(s)
- Stephanie M. Correa
- Department of Medicine, Biomedical Genetics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | | | - Ravi S. Kahlon
- Department of Medicine, Biomedical Genetics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Michelle C. Musson
- Department of Medicine, Biomedical Genetics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Gerrit J. Bouma
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Eva M. Eicher
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Kenneth H. Albrecht
- Department of Medicine, Biomedical Genetics, Boston University School of Medicine, Boston, Massachusetts, United States of America
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail:
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155
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Heaney JD, Anderson EL, Michelson MV, Zechel JL, Conrad PA, Page DC, Nadeau JH. Germ cell pluripotency, premature differentiation and susceptibility to testicular teratomas in mice. Development 2012; 139:1577-86. [PMID: 22438569 DOI: 10.1242/dev.076851] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Testicular teratomas result from anomalies in germ cell development during embryogenesis. In the 129 family of inbred strains of mice, teratomas initiate around embryonic day (E) 13.5 during the same developmental period in which female germ cells initiate meiosis and male germ cells enter mitotic arrest. Here, we report that three germ cell developmental abnormalities, namely continued proliferation, retention of pluripotency, and premature induction of differentiation, associate with teratoma susceptibility. Using mouse strains with low versus high teratoma incidence (129 versus 129-Chr19(MOLF/Ei)), and resistant to teratoma formation (FVB), we found that germ cell proliferation and expression of the pluripotency factor Nanog at a specific time point, E15.5, were directly related with increased tumor risk. Additionally, we discovered that genes expressed in pre-meiotic embryonic female and adult male germ cells, including cyclin D1 (Ccnd1) and stimulated by retinoic acid 8 (Stra8), were prematurely expressed in teratoma-susceptible germ cells and, in rare instances, induced entry into meiosis. As with Nanog, expression of differentiation-associated factors at a specific time point, E15.5, increased with tumor risk. Furthermore, Nanog and Ccnd1, genes with known roles in testicular cancer risk and tumorigenesis, respectively, were co-expressed in teratoma-susceptible germ cells and tumor stem cells, suggesting that retention of pluripotency and premature germ cell differentiation both contribute to tumorigenesis. Importantly, Stra8-deficient mice had an 88% decrease in teratoma incidence, providing direct evidence that premature initiation of the meiotic program contributes to tumorigenesis. These results show that deregulation of the mitotic-meiotic switch in XY germ cells contributes to teratoma initiation.
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Affiliation(s)
- Jason D Heaney
- Department of Genetics, Case Western Reserve University, Cleveland, OH 44106, USA.
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156
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Jameson SA, Natarajan A, Cool J, DeFalco T, Maatouk DM, Mork L, Munger SC, Capel B. Temporal transcriptional profiling of somatic and germ cells reveals biased lineage priming of sexual fate in the fetal mouse gonad. PLoS Genet 2012; 8:e1002575. [PMID: 22438826 PMCID: PMC3305395 DOI: 10.1371/journal.pgen.1002575] [Citation(s) in RCA: 215] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 01/17/2012] [Indexed: 11/18/2022] Open
Abstract
The divergence of distinct cell populations from multipotent progenitors is poorly understood, particularly in vivo. The gonad is an ideal place to study this process, because it originates as a bipotential primordium where multiple distinct lineages acquire sex-specific fates as the organ differentiates as a testis or an ovary. To gain a more detailed understanding of the process of gonadal differentiation at the level of the individual cell populations, we conducted microarrays on sorted cells from XX and XY mouse gonads at three time points spanning the period when the gonadal cells transition from sexually undifferentiated progenitors to their respective sex-specific fates. We analyzed supporting cells, interstitial/stromal cells, germ cells, and endothelial cells. This work identified genes specifically depleted and enriched in each lineage as it underwent sex-specific differentiation. We determined that the sexually undifferentiated germ cell and supporting cell progenitors showed lineage priming. We found that germ cell progenitors were primed with a bias toward the male fate. In contrast, supporting cells were primed with a female bias, indicative of the robust repression program involved in the commitment to XY supporting cell fate. This study provides a molecular explanation reconciling the female default and balanced models of sex determination and represents a rich resource for the field. More importantly, it yields new insights into the mechanisms by which different cell types in a single organ adopt their respective fates.
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Affiliation(s)
| | | | | | | | | | | | | | - Blanche Capel
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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157
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Angelopoulou R, Lavranos G, Manolakou P. Sex determination strategies in 2012: towards a common regulatory model? Reprod Biol Endocrinol 2012; 10:13. [PMID: 22357269 PMCID: PMC3311596 DOI: 10.1186/1477-7827-10-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 02/22/2012] [Indexed: 12/21/2022] Open
Abstract
Sex determination is a complicated process involving large-scale modifications in gene expression affecting virtually every tissue in the body. Although the evolutionary origin of sex remains controversial, there is little doubt that it has developed as a process of optimizing metabolic control, as well as developmental and reproductive functions within a given setting of limited resources and environmental pressure. Evidence from various model organisms supports the view that sex determination may occur as a result of direct environmental induction or genetic regulation. The first process has been well documented in reptiles and fish, while the second is the classic case for avian species and mammals. Both of the latter have developed a variety of sex-specific/sex-related genes, which ultimately form a complete chromosome pair (sex chromosomes/gonosomes). Interestingly, combinations of environmental and genetic mechanisms have been described among different classes of animals, thus rendering the possibility of a unidirectional continuous evolutionary process from the one type of mechanism to the other unlikely. On the other hand, common elements appear throughout the animal kingdom, with regard to a) conserved key genes and b) a central role of sex steroid control as a prerequisite for ultimately normal sex differentiation. Studies in invertebrates also indicate a role of epigenetic chromatin modification, particularly with regard to alternative splicing options. This review summarizes current evidence from research in this hot field and signifies the need for further study of both normal hormonal regulators of sexual phenotype and patterns of environmental disruption.
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Affiliation(s)
- Roxani Angelopoulou
- Experimental Embryology Unit, Department of Histology and Embryology, Medical School, Athens University, Athens, Greece
| | - Giagkos Lavranos
- Experimental Embryology Unit, Department of Histology and Embryology, Medical School, Athens University, Athens, Greece
| | - Panagiota Manolakou
- Experimental Embryology Unit, Department of Histology and Embryology, Medical School, Athens University, Athens, Greece
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158
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Griswold MD, Hogarth CA, Bowles J, Koopman P. Initiating meiosis: the case for retinoic acid. Biol Reprod 2012; 86:35. [PMID: 22075477 DOI: 10.1095/biolreprod.111.096610] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The requirement for vitamin A in reproduction and development was first determined from studies of nutritional deficiencies. Subsequent research has shown that embryonic development and both male and female reproduction are modulated by retinoic acid (RA), the active form of vitamin A. Because RA is active in multiple developmental systems, its synthesis, transport, and degradation are tightly regulated in different tissues. A growing body of evidence implicates RA as a requirement for the initiation of meiosis in both male and female mammals, resulting in a mechanistic model involving the interplay of RA, RA synthesis enzymes, RA receptors, and degradative cytochrome P450 enzymes in this system. Recently, that model has been challenged, prompting a review of the established paradigm. While it remains possible that additional molecules may be involved in regulating entry into meiosis, the weight of evidence supporting a key role for RA is incontrovertible.
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Affiliation(s)
- Michael D Griswold
- School of Molecular Biosciences, Washington State University, Pullman, 99164, USA.
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159
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Baillet A, Mandon-Pépin B, Veitia R, Cotinot C. [Genetics of early ovarian differentiation: recent data]. Biol Aujourdhui 2012; 205:201-21. [PMID: 22251856 DOI: 10.1051/jbio/2011021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Indexed: 11/14/2022]
Abstract
Early ovarian development has long been thought of as a default pathway switched on passively by the absence of SRY gene. Recent genetic and transcriptomic studies challenge this view and show that two master pathways simultaneously repress male-specific genes and activate female-specific genetic cascades. This antagonistic action is maintained from embryonic stages to adulthood. The differentiation of the ovarian somatic component is regulated by both the forkhead transcription factor FOXL2 (alone or in combination with oestrogens according to the species) and β-catenin pathway activated by Wnt4 and Rspo1. The sex-specific change in the fate of primordial germ cells depends on the gonad environment. Female gonocytes actively proliferate by mitosis then enter meiosis I until the diplotene stage. Primordial follicle formation occurs when oocytes are individually surrounded with pre-granulosa cells. In mammals, the population of primordial follicles serves as a resting and finite pool of oocytes available during the female reproductive life span. Recent data on factors controlling these molecular processes will be presented in this review.
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Affiliation(s)
- Adrienne Baillet
- Laboratoire de Génétique et Biologie Cellulaire, EA 4589 Université de Versailles Saint-Quentin-en-Yvelines, École Pratique des Hautes Études, 78035 Versailles Cedex, France
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160
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Childs AJ, Anderson RA. Experimental approaches to the study of human primordial germ cells. Methods Mol Biol 2012; 825:199-210. [PMID: 22144246 DOI: 10.1007/978-1-61779-436-0_15] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The survival, proliferation, and differentiation of primordial germ cells in the mammalian embryo is regulated by a complex cocktail of growth factors and interactions with surrounding somatic cells, which together form a microenvironment known as the germ cell niche. Extensive insight into the signalling pathways that regulate PGC behaviour has been provided by the study of these cells in rodent models, however little is known about the factors that regulate these processes in human PGCs. In this review, we outline experimental approaches to the culture and manipulation of the first trimester human fetal ovary, and discuss immunohistochemical and stereological approaches to detect changes in human PGC numbers and proliferation in response to treatment with exogenous growth factors.
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Affiliation(s)
- Andrew J Childs
- MRC Centre for Reproductive Health, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.
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161
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Fetal exposure to bisphenol A affects the primordial follicle formation by inhibiting the meiotic progression of oocytes. Mol Biol Rep 2011; 39:5651-7. [DOI: 10.1007/s11033-011-1372-3] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 12/12/2011] [Indexed: 01/09/2023]
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162
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Baillet A, Le Bouffant R, Volff JN, Luangpraseuth A, Poumerol E, Thépot D, Pailhoux E, Livera G, Cotinot C, Mandon-Pépin B. TOPAZ1, a novel germ cell-specific expressed gene conserved during evolution across vertebrates. PLoS One 2011; 6:e26950. [PMID: 22069478 PMCID: PMC3206057 DOI: 10.1371/journal.pone.0026950] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 10/06/2011] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND We had previously reported that the Suppression Subtractive Hybridization (SSH) approach was relevant for the isolation of new mammalian genes involved in oogenesis and early follicle development. Some of these transcripts might be potential new oocyte and granulosa cell markers. We have now characterized one of them, named TOPAZ1 for the Testis and Ovary-specific PAZ domain gene. PRINCIPAL FINDINGS Sheep and mouse TOPAZ1 mRNA have 4,803 bp and 4,962 bp open reading frames (20 exons), respectively, and encode putative TOPAZ1 proteins containing 1,600 and 1653 amino acids. They possess PAZ and CCCH domains. In sheep, TOPAZ1 mRNA is preferentially expressed in females during fetal life with a peak during prophase I of meiosis, and in males during adulthood. In the mouse, Topaz1 is a germ cell-specific gene. TOPAZ1 protein is highly conserved in vertebrates and specifically expressed in mouse and sheep gonads. It is localized in the cytoplasm of germ cells from the sheep fetal ovary and mouse adult testis. CONCLUSIONS We have identified a novel PAZ-domain protein that is abundantly expressed in the gonads during germ cell meiosis. The expression pattern of TOPAZ1, and its high degree of conservation, suggests that it may play an important role in germ cell development. Further characterization of TOPAZ1 may elucidate the mechanisms involved in gametogenesis, and particularly in the RNA silencing process in the germ line.
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Affiliation(s)
- Adrienne Baillet
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Ronan Le Bouffant
- CEA, DSV/DRR/SEGG/LDRG, Laboratory of Differentiation and Radiobiology of the Gonads, Unit of Gametogenesis and Genotoxicity, Fontenay aux Roses, France
| | - Jean Nicolas Volff
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, CNRS, INRA, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Alix Luangpraseuth
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Elodie Poumerol
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Dominique Thépot
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Eric Pailhoux
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Gabriel Livera
- CEA, DSV/DRR/SEGG/LDRG, Laboratory of Differentiation and Radiobiology of the Gonads, Unit of Gametogenesis and Genotoxicity, Fontenay aux Roses, France
| | - Corinne Cotinot
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
| | - Béatrice Mandon-Pépin
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- ENVA, Maisons Alfort, France
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163
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Chassot AA, Gregoire EP, Lavery R, Taketo MM, de Rooij DG, Adams IR, Chaboissier MC. RSPO1/β-catenin signaling pathway regulates oogonia differentiation and entry into meiosis in the mouse fetal ovary. PLoS One 2011; 6:e25641. [PMID: 21991325 PMCID: PMC3185015 DOI: 10.1371/journal.pone.0025641] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 09/08/2011] [Indexed: 11/19/2022] Open
Abstract
Differentiation of germ cells into male gonocytes or female oocytes is a central event in sexual reproduction. Proliferation and differentiation of fetal germ cells depend on the sex of the embryo. In male mouse embryos, germ cell proliferation is regulated by the RNA helicase Mouse Vasa homolog gene and factors synthesized by the somatic Sertoli cells promote gonocyte differentiation. In the female, ovarian differentiation requires activation of the WNT/β-catenin signaling pathway in the somatic cells by the secreted protein RSPO1. Using mouse models, we now show that Rspo1 also activates the WNT/β-catenin signaling pathway in germ cells. In XX Rspo1−/− gonads, germ cell proliferation, expression of the early meiotic marker Stra8, and entry into meiosis are all impaired. In these gonads, impaired entry into meiosis and germ cell sex reversal occur prior to detectable Sertoli cell differentiation, suggesting that β-catenin signaling acts within the germ cells to promote oogonial differentiation and entry into meiosis. Our results demonstrate that RSPO1/β-catenin signaling is involved in meiosis in fetal germ cells and contributes to the cellular decision of germ cells to differentiate into oocyte or sperm.
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Affiliation(s)
- Anne-Amandine Chassot
- INSERM, U636, Nice, France
- Université de Nice-Sophia Antipolis, Laboratoire de Génétique du Développement Normal et Pathologique, Nice, France
| | - Elodie P. Gregoire
- INSERM, U636, Nice, France
- Université de Nice-Sophia Antipolis, Laboratoire de Génétique du Développement Normal et Pathologique, Nice, France
| | - Rowena Lavery
- INSERM, U636, Nice, France
- Université de Nice-Sophia Antipolis, Laboratoire de Génétique du Développement Normal et Pathologique, Nice, France
| | - Makoto M. Taketo
- Department of Pharmacology, Graduate School of Medicine, Kyoto University Yoshida-Konoé-cho, Sakyo, Kyoto, Japan
| | - Dirk G. de Rooij
- Center for Reproductive Medicine, Academic Medical Center, Amsterdam, The Netherlands
- Department of Endocrinology and Metabolism, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ian R. Adams
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, Scotland
| | - Marie-Christine Chaboissier
- INSERM, U636, Nice, France
- Université de Nice-Sophia Antipolis, Laboratoire de Génétique du Développement Normal et Pathologique, Nice, France
- * E-mail:
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164
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Sommer JR, Jackson LR, Simpson SG, Collins EB, Piedrahita JA, Petters RM. Transgenic Stra8-EYFP pigs: a model for developing male germ cell technologies. Transgenic Res 2011; 21:383-92. [PMID: 21826492 DOI: 10.1007/s11248-011-9542-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 07/22/2011] [Indexed: 01/02/2023]
Abstract
The male germ line in mammals is composed of self-renewing cells, spermatogonia, the meiotic spermatocytes and spermiogenic spermatids. Identification of these cell stages in vitro has been problematic. Transgenic animals expressing a marker gene with a promoter specific to certain cell stages in the testis would be a useful approach to identifying these cells in a viable state. Towards this end, we have produced transgenic pigs expressing mitochondrial localized enhanced yellow fluorescent protein (EYFP-mito) under control of the germ cell specific Stimulated by Retinoic Acid 8 (Stra8) promoter. Stra8 has been shown to be expressed in pre-meiotic germ cells of mice. Twelve clones harboring the Stra8-EYFP-mito transgene were produced. Analysis by Western blot indicated that expression of the transgene was limited to testicular tissue in the transgenic pigs. Single cells and seminiferous tubules were cultured in vitro and subsequently examined with epifluorescent microscopy. Expression of EYFP was noted in cells cultured for up to 5 days. Both EYFP-mito and STRA8 antibodies were shown to bind and co-localize in seminiferous tubule cells in whole mounts and in histological sections. EYFP-mito in the transgenic pigs co-localized with the endogenous stem cell marker, NANOG. Expression of the Stra8-EYFP transgene in spermatogenic cells indicates that these pigs will be useful by providing labelled cells for use in such technologies such as germ cell transplantation and in vitro spermatogenic studies.
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Affiliation(s)
- Jeffrey R Sommer
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695-7621, USA
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Zhang L, Tang J, Haines CJ, Feng HL, Lai L, Teng X, Han Y. c-kit and its related genes in spermatogonial differentiation. SPERMATOGENESIS 2011; 1:186-194. [PMID: 22319667 DOI: 10.4161/spmg.1.3.17760] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 08/13/2011] [Accepted: 08/15/2011] [Indexed: 11/19/2022]
Abstract
Spermatogenesis is the process of production of male gametes from SSCs. The SSCs are the stem cells that differentiate into male gametes in the testis. in the mean time, the Spg are remarkable for their potential multiple trans-differentiations, which make them greatly invaluable for clinical applications. However, the molecular mechanism controlling differentiation of the Spg is still not clear. Among the discovered spermatogenesis-related genes, c-kit seems to be expressed first by the Spgs thus may play a central role in switching on the differentiation process. Expression of Kit and the activation of the Kit/Kitl pathway coincide with the start of differentiation of Spgs. Several genes have been discovered to be related to the Kit/Kitl pathway. in this review, we have summarized the recent discoveries of c-kit and the Kit/Kitl pathway-related genes in the spermatogenic cells during different stages of spermatogenesis.
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Affiliation(s)
- Lei Zhang
- Department of Obstetrics and Gynaecology; Prince of Wales Hospital; The Chinese University of Hong Kong; Hong Kong
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166
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Childs AJ, Cowan G, Kinnell HL, Anderson RA, Saunders PTK. Retinoic Acid signalling and the control of meiotic entry in the human fetal gonad. PLoS One 2011; 6:e20249. [PMID: 21674038 PMCID: PMC3108594 DOI: 10.1371/journal.pone.0020249] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 04/28/2011] [Indexed: 12/24/2022] Open
Abstract
The development of mammalian fetal germ cells along oogenic or spermatogenic fate trajectories is dictated by signals from the surrounding gonadal environment. Germ cells in the fetal testis enter mitotic arrest, whilst those in the fetal ovary undergo sex-specific entry into meiosis, the initiation of which is thought to be mediated by selective exposure of fetal ovarian germ cells to mesonephros-derived retinoic acid (RA). Aspects of this model are hard to reconcile with the spatiotemporal pattern of germ cell differentiation in the human fetal ovary, however. We have therefore examined the expression of components of the RA synthesis, metabolism and signalling pathways, and their downstream effectors and inhibitors in germ cells around the time of the initiation of meiosis in the human fetal gonad. Expression of the three RA-synthesising enzymes, ALDH1A1, 2 and 3 in the fetal ovary and testis was equal to or greater than that in the mesonephros at 8–9 weeks gestation, indicating an intrinsic capacity within the gonad to synthesise RA. Using immunohistochemistry to detect RA receptors RARα, β and RXRα, we find germ cells to be the predominant target of RA signalling in the fetal human ovary, but also reveal widespread receptor nuclear localization indicative of signalling in the testis, suggesting that human fetal testicular germ cells are not efficiently shielded from RA by the action of the RA-metabolising enzyme CYP26B1. Consistent with this, expression of CYP26B1 was greater in the human fetal ovary than testis, although the sexually-dimorphic expression patterns of the germ cell-intrinsic regulators of meiotic initiation, STRA8 and NANOS2, appear conserved. Finally, we demonstrate that RA induces a two-fold increase in STRA8 expression in cultures of human fetal testis, but is not sufficient to cause widespread meiosis-associated gene expression. Together, these data indicate that while local production of RA within the fetal ovary may be important in regulating the onset of meiosis in the human fetal ovary, mechanisms other than CYP26B1-mediated metabolism of RA may exist to inhibit the entry of germ cells into meiosis in the human fetal testis.
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Affiliation(s)
- Andrew J Childs
- Medical Research Council Human Reproductive Sciences Unit, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom.
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167
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Lavery R, Lardenois A, Ranc-Jianmotamedi F, Pauper E, Gregoire EP, Vigier C, Moreilhon C, Primig M, Chaboissier MC. XY Sox9 embryonic loss-of-function mouse mutants show complete sex reversal and produce partially fertile XY oocytes. Dev Biol 2011; 354:111-22. [DOI: 10.1016/j.ydbio.2011.03.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 03/18/2011] [Accepted: 03/28/2011] [Indexed: 10/18/2022]
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168
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Dyce PW, Shen W, Huynh E, Shao H, Villagómez DA, Kidder GM, King WA, Li J. Analysis of Oocyte-Like Cells Differentiated from Porcine Fetal Skin-Derived Stem Cells. Stem Cells Dev 2011; 20:809-19. [DOI: 10.1089/scd.2010.0395] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Paul W. Dyce
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
| | - Wei Shen
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
- Laboratory of Germ Cell Biology, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, China
| | - Evanna Huynh
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
| | - Hua Shao
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
| | - Daniel A.F. Villagómez
- Department of Biomedical Science, University of Guelph, Guelph, Ontario, Canada
- Departamento de Producción Animal, Universidad de Guadalajara, Zapopan, México
| | - Gerald M. Kidder
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario and Children's Health Research Institute, London, Ontario, Canada
| | - W. Allan King
- Department of Biomedical Science, University of Guelph, Guelph, Ontario, Canada
| | - Julang Li
- Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
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169
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Licensing of gametogenesis, dependent on RNA binding protein DAZL, as a gateway to sexual differentiation of fetal germ cells. Proc Natl Acad Sci U S A 2011; 108:7443-8. [PMID: 21504946 DOI: 10.1073/pnas.1104501108] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mammalian oocytes and spermatozoa derive from fetal cells shared by the sexes. These primordial germ cells (PGCs) migrate to the developing somatic gonad, giving rise to oocytes or spermatozoa. These opposing sexual fates are determined not by the PGCs' own sex chromosome constitution (XX or XY), but by the sexual identity of the fetal gonad that they enter. We asked whether PGCs undergo a developmental transition that enables them to respond to feminizing or masculinizing cues from fetal ovary or testis. We conducted in vivo genetic studies of DAZL, an RNA-binding protein expressed in both ovarian and testicular germ cells. We found that germ cells in C57BL/6 Dazl--deficient fetuses-whether XX or XY--migrate to the gonad but do not develop either male or female features. Instead, they remain in a sexually undifferentiated state similar to that of migrating PGCs. Thus, germ cells in C57BL/6 Dazl-deficient fetuses do not respond to sexual cues from ovary or testis, whereas the earlier processes of germ cell specification and migration are unaffected. We propose that PGCs of both XX and XY fetuses undergo licensing, an active developmental transition that enables the resultant gametogenesis-competent cells to respond to feminizing or masculinizing cues produced by the fetal ovary or testis and hence to embark on oogenesis or spermatogenesis. In C57BL/6 mice, Dazl is required for licensing. Licensing serves as a gateway from the embryonic processes shared between the sexes--germ cell specification and migration--to the sex-specific pathways of oogenesis and spermatogenesis.
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170
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Strauss TJ, Castrillon DH, Hammes SR. GATA-like protein-1 (GLP-1) is required for normal germ cell development during embryonic oogenesis. Reproduction 2011; 141:173-81. [DOI: 10.1530/rep-10-0376] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Oogenesis and primordial follicle formation are tightly linked processes, requiring organized and precisely timed communication between somatic and germ cells. Deviations in ovarian cell cross talk, or aberrant gene expression within one of the cell populations, can lead to follicle loss or dysfunction, resulting in infertility. Expression of GATA-like protein-1 (GLP-1) in ovarian somatic cells is required for normal fertility in female mice, as GLP-1 deficiency leads to the absence of oocytes at birth. However, the timing and nature of this germ cell loss is not well understood. In this study, we characterize the embryonic germ cell loss in GLP-1 null mice. Quantitative PCR demonstrates that ovarian Glp-1 mRNA is expressed in a bimodal pattern during embryogenesis, peaking at E13.5–14.5 and again at birth. In contrast, adult ovaries express low but detectable levels of Glp-1 mRNA. Analysis of developing GLP-1 null mouse ovaries shows that germ cells are appropriately specified and migrate normally to nascent gonads. Upon arrival at the gonad, precocious loss of germ cells begins at around E13.5. This loss is completed by birth and is accompanied by defects in the expression of genes associated with meiotic entry. Interestingly, somatic pregranulosa cells still form basement membranes surrounding germ line cysts and express mRNA encoding paracrine signaling molecules that communicate with oocytes, albeit at lower levels than normal. Together, these data imply that the somatic cell protein GLP-1 is not necessary for many pregranulosa cell functions but is required for germ cell survival.
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171
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Kumar S, Chatzi C, Brade T, Cunningham TJ, Zhao X, Duester G. Sex-specific timing of meiotic initiation is regulated by Cyp26b1 independent of retinoic acid signalling. Nat Commun 2011; 2:151. [PMID: 21224842 DOI: 10.1038/ncomms1136] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 11/15/2010] [Indexed: 01/26/2023] Open
Abstract
Sex-specific initiation of meiosis in the fetal ovary has been suggested to require retinoic acid (RA) for induction of Stra8, with expression of the RA-degrading enzyme Cyp26b1 in fetal testis delaying meiosis until postnatal development. In this study, we investigate Raldh2(-/-) mice lacking RA synthesis and signalling in mesonephros and adjacent gonad and reveal that Stra8 expression in the fetal ovary does not require RA signalling. In contrast to previous observations, we find that Stra8 is expressed in the absence of physiologically detectable levels of RA. Ketoconazole inhibition of Cyp26b1 in Raldh2(-/-) testis allows RA-independent induction of Stra8, but only when the mesonephros remains attached, pointing to a non-RA signal from the mesonephros that induces Stra8 in the adjacent gonad. These findings demonstrate that Cyp26b1 prevents the onset of meiosis by metabolizing a substrate other than RA that controls Stra8 expression, thus changing the paradigm for how studies on Cyp26 function are conducted.
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Affiliation(s)
- Sandeep Kumar
- Sanford-Burnham Medical Research Institute, Development and Aging Program, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
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172
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Zaytouni T, Efimenko EE, Tevosian SG. GATA transcription factors in the developing reproductive system. ADVANCES IN GENETICS 2011; 76:93-134. [PMID: 22099693 DOI: 10.1016/b978-0-12-386481-9.00004-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Previous work has firmly established the role for both GATA4 and FOG2 in the initial global commitment to sexual fate, but their (joint or individual) function in subsequent steps remained unknown. Hence, gonad-specific deletions of these genes in mice were required to reveal their roles in sexual development and gene regulation. The development of tissue-specific Cre lines allowed for substantial advances in the understanding of the function of GATA proteins in sex determination, gonadal differentiation and reproductive development in mice. Here we summarize the recent work that examined the requirement of GATA4 and FOG2 proteins at several critical stages in testis and ovarian differentiation. We also discuss the molecular mechanisms involved in this regulation through the control of Dmrt1 gene expression in the testis and the canonical Wnt/ß-catenin pathway in the ovary.
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Affiliation(s)
- Tamara Zaytouni
- Department of Genetics, Dartmouth Medical School, Hanover, NH, USA
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173
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174
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Rolland AD, Lehmann KP, Johnson KJ, Gaido KW, Koopman P. Uncovering gene regulatory networks during mouse fetal germ cell development. Biol Reprod 2010; 84:790-800. [PMID: 21148109 DOI: 10.1095/biolreprod.110.088443] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The commitment of germ cells to either oogenesis or spermatogenesis occurs during fetal gonad development: germ cells enter meiosis or mitotic arrest, depending on whether they reside within an ovary or a testis, respectively. Despite the critical importance of this step for sexual reproduction, gene networks underlying germ cell development have remained only partially understood. Taking advantage of the W(v) mouse model, in which gonads lack germ cells, we conducted a microarray study to identify genes expressed in fetal germ cells. In addition to distinguishing genes expressed by germ cells from those expressed by somatic cells within the developing gonads, we were able to highlight specific groups of genes expressed only in female or male germ cells. Our results provide an important resource for deciphering the molecular pathways driving proper germ cell development and sex determination and will improve our understanding of the etiology of human germ cell tumors that arise from dysregulation of germ cell differentiation.
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Affiliation(s)
- Antoine D Rolland
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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175
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Ewen K, Jackson A, Wilhelm D, Koopman P. A Male-Specific Role for p38 Mitogen-Activated Protein Kinase in Germ Cell Sex Differentiation in Mice1. Biol Reprod 2010; 83:1005-14. [DOI: 10.1095/biolreprod.110.086801] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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176
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Bowles J, Feng CW, Spiller C, Davidson TL, Jackson A, Koopman P. FGF9 suppresses meiosis and promotes male germ cell fate in mice. Dev Cell 2010; 19:440-9. [PMID: 20833365 DOI: 10.1016/j.devcel.2010.08.010] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 08/12/2010] [Accepted: 08/17/2010] [Indexed: 11/25/2022]
Abstract
Sex determination of mammalian germ cells occurs during fetal development and depends on signals from gonadal somatic cells. Previous studies have established that retinoic acid (RA) triggers ovarian germ cells to enter meiosis and thereby commit to oogenesis, whereas in the developing testis, the enzyme CYP26B1 degrades RA and germ cells are not induced to enter meiosis. Using in vitro and in vivo models, we demonstrate that fibroblast growth factor 9 (FGF9) produced in the fetal testis acts directly on germ cells to inhibit meiosis; in addition, FGF9 maintains expression of pluripotency-related genes and upregulates markers associated with male germ cell fate. We conclude that two independent and mutually antagonistic pathways involving RA and FGF9 act in concert to determine mammalian germ cell sexual fate commitment and support a model in which the mitosis/meiosis switch is robustly controlled by both positive and negative regulatory factors.
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Affiliation(s)
- Josephine Bowles
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
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177
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Guerquin MJ, Duquenne C, Lahaye JB, Tourpin S, Habert R, Livera G. New testicular mechanisms involved in the prevention of fetal meiotic initiation in mice. Dev Biol 2010; 346:320-30. [PMID: 20707993 DOI: 10.1016/j.ydbio.2010.08.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 07/30/2010] [Accepted: 08/03/2010] [Indexed: 11/28/2022]
Abstract
In mammals, early fetal germ cells are unique in their ability to initiate the spermatogenesis or oogenesis programs dependent of their somatic environment. In mice, female germ cells enter into meiosis at 13.5 dpc whereas in the male, germ cells undergo mitotic arrest. Recent findings indicate that Cyp26b1, a RA-degrading enzyme, is a key factor preventing initiation of meiosis in the fetal testis. Here, we report evidence for additional testicular pathways involved in the prevention of fetal meiosis. Using a co-culture model in which an undifferentiated XX gonad is cultured with a fetal or neonatal testis, we demonstrated that the testis prevented the initiation of meiosis and induced male germ cell differentiation in the XX gonad. This testicular effect disappeared when male meiosis starts in the neonatal testis and was not directly due to Cyp26b1 expression. Moreover, neither RA nor ketoconazole, an inhibitor of Cyp26b1, completely prevented testicular inhibition of meiosis in co-cultured ovary. We found that secreted factor(s), with molecular weight greater than 10 kDa contained in conditioned media from cultured fetal testes, inhibited meiosis in the XX gonad. Lastly, although both Sertoli and interstitial cells inhibited meiosis in XX germ cells, only interstitial cells induced mitotic arrest in germ cell. In conclusion, our results demonstrate that male germ cell determination is supported by additional non-retinoid secreted factors inhibiting both meiosis and mitosis and produced by the testicular somatic cells during fetal and neonatal life.
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Affiliation(s)
- Marie-Justine Guerquin
- aboratory of Differentiation and Radiobiology ofGonads, Unit of Gametogenesis and Genotoxicity, UMR-U566, INSERM, U566, F_92265 Fontenay-aux-roses, France
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178
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Abstract
Primordial germ cells (PGCs) are embryonic progenitors for the gametes. In the gastrulating mouse embryo, a small group of cells begin expressing a unique set of genes and so commit to the germline. Over the next 3-5 days, these PGCs migrate anteriorly and increase rapidly in number via mitotic division before colonizing the newly formed gonads. PGCs then express a different set of unique genes, their inherited epigenetic imprint is erased and an individual methylation imprint is established, and for female PGCs, the silent X chromosome is reactivated. At this point, germ cells (GCs) commit to either a female or male sexual lineage, denoted by meiosis entry and mitotic arrest, respectively. This developmental program is determined by cues emanating from the somatic environment.
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Affiliation(s)
- Katherine A Ewen
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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179
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Bowles J, Koopman P. Sex determination in mammalian germ cells: extrinsic versus intrinsic factors. Reproduction 2010; 139:943-58. [DOI: 10.1530/rep-10-0075] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mammalian germ cells do not determine their sexual fate based on their XX or XY chromosomal constitution. Instead, sexual fate is dependent on the gonadal environment in which they develop. In a fetal testis, germ cells commit to the spermatogenic programme of development during fetal life, although they do not enter meiosis until puberty. In a fetal ovary, germ cells commit to oogenesis by entering prophase of meiosis I. Although it was believed previously that germ cells are pre-programmed to enter meiosis unless they are actively prevented from doing so, recent results indicate that meiosis is triggered by a signaling molecule, retinoic acid (RA). Meiosis is avoided in the fetal testis because a male-specifically expressed enzyme actively degrades RA during the critical time period. Additional extrinsic factors are likely to influence sexual fate of the germ cells, and in particular, we postulate that an additional male-specific fate-determining factor or factors is involved. The full complement of intrinsic factors that underlie the competence of gonadal germ cells to respond to RA and other extrinsic factors is yet to be defined.
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180
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Local signalling environments and human male infertility: what we can learn from mouse models. Expert Rev Mol Med 2010; 12:e15. [PMID: 20456819 DOI: 10.1017/s1462399410001468] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Infertility is one of the most prevalent public health problems facing young adult males in today's society. A clear, treatable cause of infertility cannot be determined in a large number of these patients, and a growing body of evidence suggests that infertility in many of these men may be due to genetic causes. Studies using mouse knockout technology have been integral for examination of normal spermatogenesis and to identify proteins essential for this process, which in turn are candidate genes for human male infertility. Successful spermatogenesis depends on a delicate balance of local signalling factors, and this review focuses on the genes that encode these factors. Normal functioning of all testicular cell types is essential for fertility and might also be crucial to prevent germ cell oncogenesis. Analysis of these signalling processes in spermatogenesis using mouse models has provided investigators with an invaluable tool to effectively translate basic science research to the research of human disease and infertility.
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181
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Zhang P, Lv LX, Xing WJ. Early Meiotic-Specific Protein Expression in Post-natal Rat Ovaries. Reprod Domest Anim 2010; 45:e447-53. [DOI: 10.1111/j.1439-0531.2010.01599.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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182
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Pazin DE, Albrecht KH. Developmental expression of Smoc1 and Smoc2 suggests potential roles in fetal gonad and reproductive tract differentiation. Dev Dyn 2010; 238:2877-90. [PMID: 19842175 DOI: 10.1002/dvdy.22124] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
SMOC1 and SMOC2 are matricellular proteins thought to influence growth factor signaling, migration, proliferation, and angiogenesis. We examined the expression and regulation of Smoc1 and Smoc2 in fetal gonad/mesonephros complexes to discover possible roles for these genes in gonad and mesonephros development. Smoc1 was upregulated at approximately E10.75 in a center-to-poles wave in pre-Sertoli and pre-granulosa cells and its expression was greatly reduced in Wt1, Sf1, and Fog2 mutants. After E13.5, Smoc1 was downregulated in an anterior-to-posterior wave in granulosa cells but persisted in Sertoli cells, suggesting a sexually dimorphic requirement in supporting cell lineage differentiation. Smoc2 was expressed in Leydig cells, mesonephroi, and Wnt4 mutant ovaries, but not wildtype ovaries. Using organ culture, we determined that Smoc2 expression was dependent on Hedgehog signaling in testes, mesonephroi, and kidneys. Overall, these results demonstrate that SMOC1 and SMOC2 may mediate intercellular signaling and cell type-specific differentiation during gonad and reproductive tract development.
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Affiliation(s)
- Dorothy E Pazin
- Genetics Program, Department of Medicine, and Graduate Program in Genetics and Genomics, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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183
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Antonangeli F, Giampietri C, Petrungaro S, Filippini A, Ziparo E. Expression profile of a 400-bp Stra8 promoter region during spermatogenesis. Microsc Res Tech 2010; 72:816-22. [PMID: 19378319 DOI: 10.1002/jemt.20724] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Although numerous markers have been helpful in isolating and enriching spermatogonial stem cells (SSCs), such as Thy-1 and GFR alpha-1, no specific marker for this cell type has been identified so far. A 400-bp regulatory region of the stimulated by retinoic acid gene 8 (Stra8) promoter was reported to direct gene expression into SSCs and we have recently generated a new transgenic mouse model harboring the enhanced green fluorescent protein (EGFP) downstream of this Stra8 promoter. In this study, a detailed analysis of the EGFP expression pattern in the testis was carried out, showing that the transgene was expressed in meiotic and postmeiotic germ cells and not in undifferentiated germ cells. These findings were supported by confocal microscopy and flow cytometric analyses, and do not agree with the previous report concerning the 400-bp Stra8 promoter activity.
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Affiliation(s)
- Fabrizio Antonangeli
- Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy
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184
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Yamaji M, Tanaka T, Shigeta M, Chuma S, Saga Y, Saitou M. Functional reconstruction of NANOS3 expression in the germ cell lineage by a novel transgenic reporter reveals distinct subcellular localizations of NANOS3. Reproduction 2010; 139:381-93. [DOI: 10.1530/rep-09-0373] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Mutations of RNA-binding proteins such as NANOS3, TIAL1, and DND1 in mice have been known to result in the failure of survival and/or proliferation of primordial germ cells (PGCs) soon after their fate is specified (around embryonic day (E) 8.0), leading to the infertility of these animals. However, the mechanisms of actions of these RNA-binding proteins remain largely unresolved. As a foundation to explore the role of these RNA-binding proteins in germ cells, we established a novel transgenic reporter strain that expresses NANOS3 fused with EGFP under the control of Nanos3 regulatory elements. NANOS3–EGFP exhibited exclusive expression in PGCs as early as E7.25, and continued to be expressed in female germ cells until around E14.5 and in male germ cells throughout the fetal period with declining expression levels after E16.5. NANOS3–EGFP resumed strong expression in postnatal spermatogonia and continued to be expressed in undifferentiated spermatogonial cells in adults. Importantly, the Nanos3–EGFP transgene rescued the sterile phenotype of Nanos3 homozygous mutants, demonstrating the functional equivalency of NANOS3–EGFP with endogenous NANOS3. We found that throughout germ cell development, a predominant amount of NANOS3–EGFP co-localized with TIAL1 (also known as TIAR) and phosphorylated eukaryotic initiation factor 2α, markers for the stress granules, whereas a fraction of it showed co-localization with DCP1A, a marker for the processing bodies. On the other hand, NANOS3–EGFP did not co-localize with Tudor domain-containing protein 1, a marker for the intermitochondrial cements, in spermatogenic cells. These findings unveil the presence of distinct posttranscriptional regulations in PGCs soon after their specification, for which RNA-binding proteins such as NANOS3 and TIAL1 would play critical functions.
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185
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Naillat F, Prunskaite-Hyyryläinen R, Pietilä I, Sormunen R, Jokela T, Shan J, Vainio SJ. Wnt4/5a signalling coordinates cell adhesion and entry into meiosis during presumptive ovarian follicle development. Hum Mol Genet 2010; 19:1539-50. [PMID: 20106871 DOI: 10.1093/hmg/ddq027] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Germ cells are the foundation of an individual, since they generate the gametes and provide the unique genome established through meiosis. The sex-specific fate of the germline in mammals is thought to be controlled by somatic signals, which are still poorly characterized. We demonstrate here that somatic Wnt signalling is crucial for the control of female germline development. Wnt-4 maintains germ cell cysts and early follicular gene expression and provides a female pattern of E-cadherin and beta-catenin expression within the germ cells. In addition, we find that Stra8 expression is downregulated and the Cyp26b1 gene is expressed ectopically in the partially masculinized Wnt-4-deficient ovary. Wnt-4 may control meiosis via these proteins since the Cyp26b1 enzyme is known to degrade retinoic acid (RA) and inhibit meiosis in the male embryo, and Stra8 induces meiosis in the female through RA. Reintroduction of a Wnt-4 signal to the partially masculinized embryonic ovary, in fact, rescues the female property to a certain degree, as seen by inhibition of Cyp26b1 and induction of Irx3 gene expression. Wnt-4 deficiency allows only 20% of the germ cells to initiate meiosis in the ovary, whereas meiosis is inhibited completely in the Wnt-4/Wnt-5a double mutant. These findings indicate a critical role for Wnt signalling in meiosis. Thus, the Wnt signals are important somatic cell signals that coordinate presumptive female follicle development.
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Affiliation(s)
- Florence Naillat
- Laboratory of Developmental Biology, Department of Medical Biochemistry and Molecular Biology, Oulu Centre for Cell-Matrix Research, Institute of Biomedicine, Biocenter Oulu, University of Oulu, PO Box 5000, FIN-90220 Oulu, Finland
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186
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Wang N, Tilly JL. Epigenetic status determines germ cell meiotic commitment in embryonic and postnatal mammalian gonads. Cell Cycle 2010; 9:339-49. [PMID: 20009537 DOI: 10.4161/cc.9.2.10447] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The meiotic cell cycle is required for production of fertilization-competent gametes. Germ cell meiotic commitment requires expression of Stimulated by retinoic acid gene 8 (Stra8), which is transcriptionally activated by retinoic acid (RA). Meiotic suppression in embryonic male germ cells is believed to result from sex-specific differences in CYP26B1-catalyzed RA metabolism in the developing gonads. Here we show in mice that RA-induced Stra8 transcription is epigenetically controlled and requires a co-activator that binds proximal to the RA response elements (RAREs) in the Stra8 promoter. Embryonic male germ cells exposed in utero to the class I/II histone deacetylase (HDAC) inhibitor, trichostatin-A (TSA), show premature Stra8 activation and meiotic entry without altered Cyp26b1 expression. We also show that Stra8 expression is detectable and physiologically regulated in adult mouse ovaries. Further, oogenesis induction in adult females using TSA is associated with Stra8 activation, and these events are absent in mice deficient in the RA precursor vitamin A. Finally, all of the actions of TSA in premeiotic germ cells in vitro and in mouse ovaries in vivo can be reproduced with the small molecule HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA). Thus, the ability of RA to transcriptionally induce expression of the meiosis-commitment gene, Stra8, is epigenetically controlled and this process involves a novel co-activator that functions upstream of the RAREs. These events not only coordinate the sex-specific timing of meiotic entry during embryogenesis, but also contribute to the regulation of oogenesis in adult female mammals.
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Affiliation(s)
- Ning Wang
- Vincent Center for Reproductive Biology, Vincent Obstetrics and Gynecology Service, Massachusetts General Hospital, and Department of Obstetrics, Gynecology and Reproductive Biology, Harvard Medical School, Boston, MA, USA
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187
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Hiramatsu R, Harikae K, Tsunekawa N, Kurohmaru M, Matsuo I, Kanai Y. FGF signaling directs a center-to-pole expansion of tubulogenesis in mouse testis differentiation. Development 2010; 137:303-12. [DOI: 10.1242/dev.040519] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In mouse embryogenesis, Sry is transiently activated in a center-to-pole wavelike manner along the anteroposterior (AP) axis of developing XY gonads. However, the mechanism and significance of the center-to-pole expansion of testis initiation pathways downstream of Sry expression remain unclear. Here we demonstrate that FGF9 can act as a diffusible conductor for a poleward expansion of tubulogenic programs at early phases of testis differentiation. In XY genital ridge cultures of anterior, middle and posterior segments at 11.0-11.25 days post-coitum, male-specific activation of Sry and its target gene, Sox9, was still observed in both anterior and posterior pole segments despite their isolation from the central domain. However, high-level Sox9 expression was not maintained, resulting in the failure of testis cord organization in most pole segments. A reconstruction experiment using ROSA:lacZ middle segments showed rescue of the tubulogenic defect in the poles without any appreciable contribution of lacZ-positive gonadal parenchyma cells. A partition culture assay also showed a possible contribution of soluble/diffusible factors secreted from the gonadal center domain to proper tubulogenesis in the poles. Among various signaling factors, Fgf9 expression was significantly lower in both anterior and posterior pole segments than in the central domain. The supportive role of the central domain could be substituted by exogenous FGF9 supply, whereas reduction of Wnt4 activity did not rescue the tubulogenesis defect in the pole segments. These observations imply that center-to-pole FGF9 diffusion directs a poleward expansion of testiculogenic programs along the AP axis of developing XY gonads.
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Affiliation(s)
- Ryuji Hiramatsu
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
- Department of Molecular Embryology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka Prefectural Hospital Organization, Murodo-cho, Izumi, Osaka, 594-1101, Japan
| | - Kyoko Harikae
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Naoki Tsunekawa
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Masamichi Kurohmaru
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Isao Matsuo
- Department of Molecular Embryology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka Prefectural Hospital Organization, Murodo-cho, Izumi, Osaka, 594-1101, Japan
| | - Yoshiakira Kanai
- Department of Veterinary Anatomy, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
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188
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Tedesco M, La Sala G, Barbagallo F, De Felici M, Farini D. STRA8 shuttles between nucleus and cytoplasm and displays transcriptional activity. J Biol Chem 2009; 284:35781-93. [PMID: 19805549 PMCID: PMC2791008 DOI: 10.1074/jbc.m109.056481] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Revised: 09/22/2009] [Indexed: 12/18/2022] Open
Abstract
Stra8 (stimulated by retinoic acid 8) encodes a protein crucial for mammalian germ cells entering into premeiotic stages. Here, to elucidate the still unknown STRA8 molecular functions, we studied the cellular localization of the protein in several cell types, including premeiotic mouse germ cells and stem cell lines. We reported distinct STRA8 localization in germ and stem cell types and a heterogeneous protein distribution in the cytoplasm and nucleus of such cells suggesting that the protein can shuttle between these two compartments. Moreover, we identified specific protein motifs determining its nuclear import/export. Furthermore, we demonstrated that in transfected cell lines the nuclear import of STRA8 is an active process depending on an N-terminal basic nuclear localization signal. Moreover, its nuclear export is mainly mediated by the Exportin1 (XPO1) recognition of a nuclear export signal. Significantly, we also demonstrated that STRA8 associates with DNA and possesses transcriptional activity. These observations strongly suggest that STRA8 can exert important functions in the nucleus rather than in the cytoplasm as believed previously, likely depending on the cell type and regulated by its nuclear-cytoplasmic shuttling.
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Affiliation(s)
- Marianna Tedesco
- From the Department of Public Health and Cell Biology, University of Rome “Tor Vergata,” 00173 Rome, Italy
| | - Gina La Sala
- From the Department of Public Health and Cell Biology, University of Rome “Tor Vergata,” 00173 Rome, Italy
| | - Federica Barbagallo
- From the Department of Public Health and Cell Biology, University of Rome “Tor Vergata,” 00173 Rome, Italy
| | - Massimo De Felici
- From the Department of Public Health and Cell Biology, University of Rome “Tor Vergata,” 00173 Rome, Italy
| | - Donatella Farini
- From the Department of Public Health and Cell Biology, University of Rome “Tor Vergata,” 00173 Rome, Italy
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189
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The DM domain protein DMRT1 is a dose-sensitive regulator of fetal germ cell proliferation and pluripotency. Proc Natl Acad Sci U S A 2009; 106:22323-8. [PMID: 20007774 DOI: 10.1073/pnas.0905431106] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Dmrt1 (doublesex and mab-3 related transcription factor 1) is a conserved transcriptional regulator of male differentiation required for testicular development in vertebrates. Here, we show that in mice of the 129Sv strain, loss of Dmrt1 causes a high incidence of teratomas, whereas these tumors do not form in Dmrt1 mutant C57BL/6J mice. Conditional gene targeting indicates that Dmrt1 is required in fetal germ cells but not in Sertoli cells to prevent teratoma formation. Mutant 129Sv germ cells undergo apparently normal differentiation up to embryonic day 13.5 (E13.5), but some cells fail to arrest mitosis and ectopically express pluripotency markers. Expression analysis and chromatin immunoprecipitation identified DMRT1 target genes, whose missexpression may underlie teratoma formation. DMRT1 indirectly activates the GDNF coreceptor Ret, and it directly represses the pluripotency regulator Sox2. Analysis of human germ cell tumors reveals similar gene expression changes correlated to DMRT1 levels. Dmrt1 behaves genetically as a dose-sensitive tumor suppressor gene in 129Sv mice, and natural variation in Dmrt1 activity can confer teratoma susceptibility. This work reveals a genetic link between testicular dysgenesis, pluripotency regulation, and teratoma susceptibility that is highly sensitive to genetic background and to gene dosage.
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190
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Li H, Clagett-Dame M. Vitamin A Deficiency Blocks the Initiation of Meiosis of Germ Cells in the Developing Rat Ovary In Vivo1. Biol Reprod 2009; 81:996-1001. [DOI: 10.1095/biolreprod.109.078808] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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191
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Abstract
Two major functions of the mammalian ovary are the production of germ cells (oocytes), which allow continuation of the species, and the generation of bioactive molecules, primarily steroids (mainly estrogens and progestins) and peptide growth factors, which are critical for ovarian function, regulation of the hypothalamic-pituitary-ovarian axis, and development of secondary sex characteristics. The female germline is created during embryogenesis when the precursors of primordial germ cells differentiate from somatic lineages of the embryo and take a unique route to reach the urogenital ridge. This undifferentiated gonad will differentiate along a female pathway, and the newly formed oocytes will proliferate and subsequently enter meiosis. At this point, the oocyte has two alternative fates: die, a common destiny of millions of oocytes, or be fertilized, a fate of at most approximately 100 oocytes, depending on the species. At every step from germline development and ovary formation to oogenesis and ovarian development and differentiation, there are coordinated interactions of hundreds of proteins and small RNAs. These studies have helped reproductive biologists to understand not only the normal functioning of the ovary but also the pathophysiology and genetics of diseases such as infertility and ovarian cancer. Over the last two decades, parallel progress has been made in the assisted reproductive technology clinic including better hormonal preparations, prenatal genetic testing, and optimal oocyte and embryo analysis and cryopreservation. Clearly, we have learned much about the mammalian ovary and manipulating its most important cargo, the oocyte, since the birth of Louise Brown over 30 yr ago.
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Affiliation(s)
- Mark A Edson
- Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
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192
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Matsui Y, Tokitake Y. Primordial germ cells contain subpopulations that have greater ability to develop into pluripotential stem cells. Dev Growth Differ 2009; 51:657-67. [DOI: 10.1111/j.1440-169x.2009.01125.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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193
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Tingen C, Kim A, Woodruff TK. The primordial pool of follicles and nest breakdown in mammalian ovaries. Mol Hum Reprod 2009; 15:795-803. [PMID: 19710243 DOI: 10.1093/molehr/gap073] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The creation of the pool of follicles available for selection and ovulation is a multi-faceted, tightly regulated process that spans the period from embryonic development through to the first reproductive cycle of the organism. In mice, this development can occur in mere weeks, but in humans, it is sustained for years. Embryonic germ cell development involves the migration of primordial germs cells to the genital ridge, and the mitotic division of germ cell nuclei without complete cytokinesis to form a multi-nucleated syncytia, or germ cell nest. Through combined actions of germ cell apoptosis and somatic cell migration, the germ cell nuclei are packaged, with surrounding granulosa cells, into primordial follicles to form the initial follicle pool. Though often dismissed as quiescent and possibly uninteresting, this initial follicle pool is actually quite dynamic. In a very strictly controlled mechanism, a large portion of the initial primordial follicles formed is lost by atresia before cycling even begins. Remaining follicles can undergo alternate fates of continued dormancy or selection leading to follicular growth and differentiation. Together, the processes involved in the fate decisions of atresia, sustained dormancy, or activation carve out the follicle pool of puberty, the pool of available oocytes from which all future reproductive cycles of the female can choose. The formation of the initial and pubertal follicle pools can be predictably affected by exogenous treatment with hormones or molecules such as activin, demonstrating the ways the ovary controls the quality and quantity of germ cells maintained. Here, we review the biological processes involved in the formation of the initial follicle pool and the follicle pool of puberty, address the alternate models for regulating germ cell number and outline how the ovary quality-controls the germ cells produced.
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Affiliation(s)
- Candace Tingen
- The Department of Obstetrics and Gynecology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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194
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Morita-Fujimura Y, Tokitake Y, Matsui Y. Heterogeneity of mouse primordial germ cells reflecting the distinct status of their differentiation, proliferation and apoptosis can be classified by the expression of cell surface proteins integrin α6 and c-Kit. Dev Growth Differ 2009; 51:567-83. [DOI: 10.1111/j.1440-169x.2009.01119.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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195
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Kossack N, Meneses J, Shefi S, Nguyen HN, Chavez S, Nicholas C, Gromoll J, Turek PJ, Reijo-Pera RA. Isolation and characterization of pluripotent human spermatogonial stem cell-derived cells. Stem Cells 2009; 27:138-49. [PMID: 18927477 PMCID: PMC2729695 DOI: 10.1634/stemcells.2008-0439] [Citation(s) in RCA: 222] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Several reports have documented the derivation of pluripotent cells (multipotent germline stem cells) from spermatogonial stem cells obtained from the adult mouse testis. These spermatogonia-derived stem cells express embryonic stem cell markers and differentiate to the three primary germ layers, as well as the germline. Data indicate that derivation may involve reprogramming of endogenous spermatogonia in culture. Here, we report the derivation of human multipotent germline stem cells (hMGSCs) from a testis biopsy. The cells express distinct markers of pluripotency, form embryoid bodies that contain derivatives of all three germ layers, maintain a normal XY karyotype, are hypomethylated at the H19 locus, and express high levels of telomerase. Teratoma assays indicate the presence of human cells 8 weeks post-transplantation but limited teratoma formation. Thus, these data suggest the potential to derive pluripotent cells from human testis biopsies but indicate a need for novel strategies to optimize hMGSC culture conditions and reprogramming.
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Affiliation(s)
- Nina Kossack
- Institute for Stem Cell Biology and Regenerative Medicine, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Palo Alto, California 94304-5542, USA
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196
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Lee HJ, Pazin DE, Kahlon RS, Correa SM, Albrecht KH. Novel markers of early ovarian pre-granulosa cells are expressed in an Sry-like pattern. Dev Dyn 2009; 238:812-25. [PMID: 19301398 DOI: 10.1002/dvdy.21902] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mammalian gonad differentiation involves sexually dimorphic cell-fate decisions within the bipotential gonadal primordia. Testis differentiation is initiated by a center-to-poles wave of Sry expression that induces supporting cell precursors (SCPs) to become Sertoli rather than granulosa cells. The initiation of ovary differentiation is less well understood. We identified two novel SCP markers, 1700106J16Rik and Sprr2d, whose expression is ovary-biased during early gonad development, and altered in Wnt4, Sf1, Wt1, and Fog2 mutant gonads. In XX and XY gonads, both genes were up-regulated at approximately E11 in a center-to-poles wave, and then rapidly down-regulated in XY gonads in a center-to-poles wave, which is reminiscent of Sry expression in XY gonads. Our data suggest that 1700106J16Rik and Sprr2d may have important roles in early gonad development, and are consistent with the hypothesis that ovarian SCP differentiation occurs in a center-to-poles wave with similar timing to that of testicular SCP differentiation.
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Affiliation(s)
- Hyunjoo J Lee
- Department of Medicine, Genetics Program, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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197
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Buaas FW, Val P, Swain A. The transcription co-factor CITED2 functions during sex determination and early gonad development. Hum Mol Genet 2009; 18:2989-3001. [DOI: 10.1093/hmg/ddp237] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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198
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Nicholas CR, Chavez SL, Baker VL, Reijo Pera RA. Instructing an embryonic stem cell-derived oocyte fate: lessons from endogenous oogenesis. Endocr Rev 2009; 30:264-83. [PMID: 19366753 PMCID: PMC2726843 DOI: 10.1210/er.2008-0034] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Female reproductive potential is limited in the majority of species due to oocyte depletion. Because functional human oocytes are restricted in number and accessibility, a robust system to differentiate oocytes from stem cells would enable a thorough investigation of the genetic, epigenetic, and environmental factors affecting human oocyte development. Also, the differentiation of functional oocytes from stem cells may permit the success of human somatic cell nuclear transfer for reprogramming studies and for the production of patient-specific embryonic stem cells (ESCs). Thus, ESC-derived oocytes could ultimately help to restore fertility in women. Here, we review endogenous and ESC-derived oocyte development, and we discuss the potential and challenges for differentiating functional oocytes from ESCs.
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Affiliation(s)
- Cory R Nicholas
- Department of Obstetrics and Gynecology, Stanford University School of Medicine, Palo Alto, California 94304, USA.
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199
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Kocer A, Reichmann J, Best D, Adams IR. Germ cell sex determination in mammals. Mol Hum Reprod 2009; 15:205-13. [PMID: 19218284 PMCID: PMC2657314 DOI: 10.1093/molehr/gap008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 01/20/2009] [Accepted: 01/26/2009] [Indexed: 12/14/2022] Open
Abstract
One of the major decisions that germ cells make during their development is whether to differentiate into oocytes or sperm. In mice, the germ cells' decision to develop as male or female depends on sex-determining signalling molecules in the embryonic gonadal environment rather than the sex chromosome constitution of the germ cells themselves. In response to these sex-determining cues, germ cells in female embryos initiate oogenesis and enter meiosis, whereas germ cells in male embryos initiate spermatogenesis and inhibit meiosis until after birth. However, it is not clear whether the signalling molecules that mediate germ cell sex determination act in the developing testis or the developing ovary, or what these signalling molecules might be. Here, we review the evidence for the existence of meiosis-inducing and meiosis-preventing substances in the developing gonad, and more recent studies aimed at identifying these molecules in mice. In addition, we discuss the possibility that some of the reported effects of these factors on germ cell development may be indirect consequences of impairing sexual differentiation of gonadal somatic cells or germ cell survival. Understanding the molecular mechanisms of germ cell sex determination may provide candidate genes for susceptibility to germ cell tumours and infertility in humans.
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Affiliation(s)
| | | | | | - Ian R. Adams
- MRC Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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200
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Qin J, Guo X, Cui GH, Zhou YC, Zhou DR, Tang AF, Yu ZD, Gui YT, Cai ZM. Cluster characterization of mouse embryonic stem cell-derived pluripotent embryoid bodies in four distinct developmental stages. Biologicals 2009; 37:235-44. [PMID: 19339198 DOI: 10.1016/j.biologicals.2009.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 03/04/2009] [Accepted: 03/04/2009] [Indexed: 10/20/2022] Open
Abstract
The formation of embryoid bodies (EBs) is the principal step in the differentiation of embryonic stem (ES) cells. In this study, the morphological characteristics and gene expression patterns of EBs related to the sequential stages of embryonic development were well defined in four distinct developmental groups over 112 days of culture: early-stage EBs groups (1-7 days of differentiation), mid-stage EBs groups (9-15 days of differentiation), maturing EBs groups (17-45 days of differentiation) and matured EBs groups (50 days of differentiation). We first determined definite histological location of apoptosis within EBs and the sequential expression of molecular markers representing stem cells (Oct4, SSEA-1, Sox-2 and AKP), germ cells (Fragilis, Dazl, c-kit, StellaR, Mvh and Stra8), ectoderm (Neurod, Nestin and Neurofilament), mesoderm (Gata-1, Flk-1 and Hbb) and endoderm (AFP and Transthyretin). Our results revealed that developing EBs possess either pluripotent stem cell or germ cell states and that three-dimensional aggregates of EBs initiate mES cell differentiation during prolonged culture in vitro. Therefore, we suggest that this EB system to some extent recapitulates the early developmental processes occurring in vivo.
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Affiliation(s)
- J Qin
- Key Laboratory of Male Reproduction & Genetics of Guangdong Province, Peking University, Shenzhen Hospital, Lianhua Road 1120, FuTian District, Shenzhen 518036, PR China
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