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Le Rolle M, Massa F, Siggers P, Turchi L, Loubat A, Koo BK, Clevers H, Greenfield A, Schedl A, Chaboissier MC, Chassot AA. Arrest of WNT/β-catenin signaling enables the transition from pluripotent to differentiated germ cells in mouse ovaries. Proc Natl Acad Sci U S A 2021; 118:e2023376118. [PMID: 34301885 PMCID: PMC8325354 DOI: 10.1073/pnas.2023376118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Germ cells form the basis for sexual reproduction by producing gametes. In ovaries, primordial germ cells exit the cell cycle and the pluripotency-associated state, differentiate into oogonia, and initiate meiosis. Despite the importance of germ cell differentiation for sexual reproduction, signaling pathways regulating their fate remain largely unknown. Here, we show in mouse embryonic ovaries that germ cell-intrinsic β-catenin activity maintains pluripotency and that its repression is essential to allow differentiation and meiosis entry in a timely manner. Accordingly, in β-catenin loss-of-function and gain-of-function mouse models, the germ cells precociously enter meiosis or remain in the pluripotent state, respectively. We further show that interaction of β-catenin and the pluripotent-associated factor POU5F1 in the nucleus is associated with germ cell pluripotency. The exit of this complex from the nucleus correlates with germ cell differentiation, a process promoted by the up-regulation of Znrf3, a negative regulator of WNT/β-catenin signaling. Together, these data identify the molecular basis of the transition from primordial germ cells to oogonia and demonstrate that β-catenin is a central gatekeeper in ovarian differentiation and gametogenesis.
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Affiliation(s)
- Morgane Le Rolle
- CNRS, Inserm, Institut de Biologie Valrose, Université Côte d'Azur, Parc Valrose, 06108 Nice Cedex 2, France
| | - Filippo Massa
- CNRS, Inserm, Institut de Biologie Valrose, Université Côte d'Azur, Parc Valrose, 06108 Nice Cedex 2, France
- Inovarion, 75005 Paris, France
| | - Pam Siggers
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Oxfordshire OX11 0RD, United Kingdom
| | - Laurent Turchi
- CNRS, Inserm, Institut de Biologie Valrose, Université Côte d'Azur, Parc Valrose, 06108 Nice Cedex 2, France
- Délégation à la Recherche Clinique et à l'Innovation, Centre Hospitalier Universitaire de Nice, 06000 Nice, France
| | - Agnès Loubat
- CNRS, Inserm, Institut de Biologie Valrose, Université Côte d'Azur, Parc Valrose, 06108 Nice Cedex 2, France
| | - Bon-Kyoung Koo
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, 3584 CT Utrecht, The Netherlands
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna Biocenter, 1030 Vienna, Austria
| | - Hans Clevers
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, 3584 CT Utrecht, The Netherlands
| | - Andy Greenfield
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Oxfordshire OX11 0RD, United Kingdom
| | - Andreas Schedl
- CNRS, Inserm, Institut de Biologie Valrose, Université Côte d'Azur, Parc Valrose, 06108 Nice Cedex 2, France
| | - Marie-Christine Chaboissier
- CNRS, Inserm, Institut de Biologie Valrose, Université Côte d'Azur, Parc Valrose, 06108 Nice Cedex 2, France
| | - Anne-Amandine Chassot
- CNRS, Inserm, Institut de Biologie Valrose, Université Côte d'Azur, Parc Valrose, 06108 Nice Cedex 2, France;
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2
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Abstract
Primordial germ cells (PGCs) must complete a complex and dynamic developmental program during embryogenesis to establish the germline. This process is highly conserved and involves a diverse array of tasks required of PGCs, including migration, survival, sex differentiation, and extensive epigenetic reprogramming. A common theme across many organisms is that PGC success is heterogeneous: only a portion of all PGCs complete all these steps while many other PGCs are eliminated from further germline contribution. The differences that distinguish successful PGCs as a population are not well understood. Here, we examine variation that exists in PGCs as they navigate the many stages of this developmental journey. We explore potential sources of PGC heterogeneity and their potential implications in affecting germ cell behaviors. Lastly, we discuss the potential for PGC development to function as a multistage selection process that assesses heterogeneity in PGCs to refine germline quality.
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Affiliation(s)
- Daniel H Nguyen
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States
| | - Rebecca G Jaszczak
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States
| | - Diana J Laird
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States.
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3
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Abstract
In mammalian development, primordial germ cells (PGCs) represent the initial population of cells that are committed to the germ cell lineage. PGCs segregate early in development, triggered by signals from the extra-embryonic ectoderm. They are distinguished from surrounding cells by their unique gene expression patterns. Some of the more common genes used to identify them are Blimp1, Oct3/4, Fragilis, Stella, c-Kit, Mvh, Dazl and Gcna1. These genes are involved in regulating their migration and differentiation, and in maintaining the pluripotency of these cells. Recent research has demonstrated the possibility of obtaining PGCs, and subsequently, mature germ cells from a starting population of embryonic stem cells (ESCs) in culture. This phenomenon has been investigated using a variety of methods, and ESC lines of both mouse and human origin. Embryonic stem cells can differentiate into germ cells of both the male and female phenotype and in one case has resulted in the birth of live pups from the fertilization of oocytes with ESC derived sperm. This finding leads to the prospect of using ESC derived germ cells as a treatment for sterility. This review outlines the evolvement of germ cells from ESCs in vitro in relation to in vivo events.
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Affiliation(s)
- Deshira Saiti
- Monash Immunology and Stem Cell Laboratories, Level 3, STRIP 1 – Buildings 75, Monash University, Wellington Rd., Clayton, Australia, 3800
| | - Orly Lacham-Kaplan
- Monash Immunology and Stem Cell Laboratories, Level 3, STRIP 1 – Buildings 75, Monash University, Wellington Rd., Clayton, Australia, 3800
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4
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Arora R, Abby E, Ross ADJ, Cantu AV, Kissner MD, Castro V, Ho HYH, Livera G, Laird DJ. Meiotic onset is reliant on spatial distribution but independent of germ cell number in the mouse ovary. J Cell Sci 2016; 129:2493-9. [PMID: 27199373 DOI: 10.1242/jcs.189910] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/13/2016] [Indexed: 01/09/2023] Open
Abstract
Mouse ovarian germ cells enter meiosis in a wave that propagates from anterior to posterior, but little is known about contribution of germ cells to initiation or propagation of meiosis. In a Ror2 mutant with diminished germ cell number and migration, we find that overall timing of meiotic initiation is delayed at the population level. We use chemotherapeutic depletion to exclude a profoundly reduced number of germ cells as a cause for meiotic delay. We rule out sex reversal or failure to specify somatic support cells as contributors to the meiotic phenotype. Instead, we find that anomalies in the distribution of germ cells as well as gonad shape in mutants contribute to aberrant initiation of meiosis. Our analysis supports a model of meiotic initiation via diffusible signal(s), excludes a role for germ cells in commencing the meiotic wave and furnishes the first phenotypic demonstration of the wave of meiotic entry. Finally, our studies underscore the importance of considering germ cell migration defects while studying meiosis to discern secondary effects resulting from positioning versus primary meiotic entry phenotypes.
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Affiliation(s)
- Ripla Arora
- Department of Ob/Gyn and Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Emilie Abby
- University Paris Diderot, Sorbonne Paris Cite, Laboratory of Development of the Gonads; CEA, DSV, iRCM, SCSR, LDG; INSERM, Unit of Genetic Stability, Stem cells and Radiation, UMR-967; University Paris-Sud, Fontenay-aux-Roses F-92265, France
| | - Adam D J Ross
- Department of Ob/Gyn and Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Andrea V Cantu
- Department of Ob/Gyn and Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Michael D Kissner
- Department of Ob/Gyn and Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Vianca Castro
- Department of Ob/Gyn and Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
| | - Hsin-Yi Henry Ho
- Department of Cell Biology and Human Anatomy, University of California, Davis School of Medicine, 4422 Tupper Hall, Davis, CA 95616, USA
| | - Gabriel Livera
- University Paris Diderot, Sorbonne Paris Cite, Laboratory of Development of the Gonads; CEA, DSV, iRCM, SCSR, LDG; INSERM, Unit of Genetic Stability, Stem cells and Radiation, UMR-967; University Paris-Sud, Fontenay-aux-Roses F-92265, France
| | - Diana J Laird
- Department of Ob/Gyn and Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA 94143, USA
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5
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Jorgensen JS. Defining the neighborhoods that escort the oocyte through its early life events and into a functional follicle. Mol Reprod Dev 2013; 80:960-76. [PMID: 24105719 PMCID: PMC3980676 DOI: 10.1002/mrd.22232] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 08/15/2013] [Indexed: 01/19/2023]
Abstract
The ovary functions to chaperone the most precious cargo for female individuals, the oocyte, thereby allowing the passage of genetic material to subsequent generations. Within the ovary, single oocytes are surrounded by a legion of granulosa cells inside each follicle. These two cell types depend upon one another to support follicle formation and oocyte survival. The infrastructure and events that work together to ultimately form these functional follicles within the ovary are unprecedented, given that the oocyte originates as a cell like all other neighboring cells within the embryo prior to gastrulation. This review discusses the journey of the germ cell in the context of the developing female mouse embryo, with a focus on specific signaling events and cell-cell interactions that escort the primordial germ cell as it is specified into the germ cell fate, migrates through the hindgut into the gonad, differentiates into an oocyte, and culminates upon formation of the primordial and then primary follicle.
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Affiliation(s)
- Joan S Jorgensen
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin
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6
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Chen B, Zhang L, Tang J, Feng X, Feng Y, Liang G, Wang L, Feng Y, Li L, De Felici M, Shi Q, Shen W. Recovery of functional oocytes from cultured premeiotic germ cells after kidney capsule transplantation. Stem Cells Dev 2012; 22:567-80. [PMID: 22978409 DOI: 10.1089/scd.2012.0436] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The efficiency of in vitro culture systems for a premeiotic female germ cell is still low, mostly because of our incomplete understanding of the mechanisms controlling oogenesis and the obvious difficulties in reproducing the complex in vivo environment of such a process under in vitro conditions. Here we explored the possibility of recovering the developmental potential of mouse oocytes generated in vitro from premeiotic germ cells by transplantation under a kidney capsule of adult animals. To this aim, mouse embryonic ovaries of 12.5 days postcoitum cultured in vitro in a serum-free medium for 7 or 14 days, were transplanted beneath the kidney capsule of immunodeficient mice and analyzed after 21 (7+21 group) or 14 days (14+14 group). Cultured ovaries before transplantation showed delayed oocyte meiotic progression and follicle development. Interestingly, grafted ovaries of both groups, especially those of the 7+21 group, seemed able to restore the reproductive cycle of recipients. While the almost complete absence of primordial follicles was observed in grafted ovaries, oocytes from these ovaries showed transcript levels of genes associated to oocyte maturation similar to control. Moreover, the developmental stage of follicles and oocytes of the 7+21 group ovaries were comparable to that of 21 days post partum in vivo ovaries, whereas significant developmental delay were found in the 14+14 group ovaries. Nevertheless, oocytes retrieved from transplanted ovaries of both groups matured (around 80%) and were fertilized in vitro (around 20%-45%). Two-cell embryos from the fertilized oocytes developed to hatching blastocysts (about 50%) or gave rise to healthy live offspring (from 6% to 10%) when transplanted in a host mother. In conclusion, our results indicate that premeiotic female germ cells cultured in vitro up to primordial/primary follicle stages preserve their capability to complete oogenesis and can be fertilized and generate live pups after transplantation into a suitable in vivo environment.
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Affiliation(s)
- Bo Chen
- Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, Qingdao Agricultural University, Qingdao, China
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7
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Notarianni E. Reinterpretation of evidence advanced for neo-oogenesis in mammals, in terms of a finite oocyte reserve. J Ovarian Res 2011; 4:1. [PMID: 21211009 PMCID: PMC3024995 DOI: 10.1186/1757-2215-4-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 01/06/2011] [Indexed: 12/22/2022] Open
Abstract
The central tenet of ovarian biology, that the oocyte reserve in adult female mammals is finite, has been challenged over recent years by proponents of neo-oogenesis, who claim that germline stem cells exist in the ovarian surface epithelium or the bone marrow. Currently opinion is divided over these claims, and further scrutiny of the evidence advanced in support of the neo-oogenesis hypothesis is warranted - especially in view of the enormous implications for female fertility and health. This article contributes arguments against the hypothesis, providing alternative explanations for key observations, based on published data. Specifically, DNA synthesis in germ cells in the postnatal mouse ovary is attributed to mitochondrial genome replication, and to DNA repair in oocytes lagging in meiotic progression. Lines purported to consist of germline stem cells are identified as ovarian epithelium or as oogonia, from which cultures have been derived previously. Effects of ovotoxic treatments are found to negate claims for the existence of germline stem cells. And arguments are presented for the misidentification of ovarian somatic cells as de novo oocytes. These clarifications, if correct, undermine the concept that germline stem cells supplement the oocyte quota in the postnatal ovary; and instead comply with the theory of a fixed, unregenerated reserve. It is proposed that acceptance of the neo-oogenesis hypothesis is erroneous, and may effectively impede research in areas of ovarian biology. To illustrate, a novel explanation that is consistent with orthodox theory is provided for the observed restoration of fertility in chemotherapy-treated female mice following bone marrow transplantation, otherwise interpreted by proponents of neo-oogenesis as involving stimulation of endogenous germline stem cells. Instead, it is proposed that the chemotherapeutic regimens induce autoimmunity to ovarian antigens, and that the haematopoietic chimaerism produced by bone marrow transplantation circumvents activation of an autoreactive response, thereby rescuing ovarian function. The suggested mechanism draws from animal models of autoimmune ovarian disease, which implicate dysregulation of T cell regulatory function; and from a surmised role for follicular apoptosis in the provision of ovarian autoantigens, to sustain self-tolerance during homeostasis. This interpretation has direct implications for fertility preservation in women undergoing chemotherapy.
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Affiliation(s)
- Elena Notarianni
- Department of Biological & Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
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8
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Fukunaga N, Teramura T, Onodera Y, Takehara T, Fukuda K, Hosoi Y. Leukemia inhibitory factor (LIF) enhances germ cell differentiation from primate embryonic stem cells. Cell Reprogram 2010; 12:369-76. [PMID: 20698776 DOI: 10.1089/cell.2009.0097] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recently, several research groups have shown that germ cells can be produced in vitro from pluripotent embryonic stem cells (ESCs). In the mouse, live births of offspring using germ cells induced from ESCs in vitro have been reported. Furthermore, some efficient methods for inducing the useful number of germ cells from ESCs have also been developed. On the other hand, in primates, despite the appearances of germ cell-like cells including meiotic cells were observed by spontaneous differentiation or introducing transgenes, it has not been determined whether fully functional germ cells can be derived from ESCs. To elucidate the property for the germ cells induced from primate ESCs, specification of the promoting factors for the germ cell development and improving the efficiency of germ cell derivation are essential. Leukemia inhibitory factor (LIF) has been reported as one of the important factors for mouse primordial germ cell (PGC) survival in vitro. However, the effects of LIF on germ cell formation from pluripotent cells of primates have not been examined. The aim of this study is to determine whether LIF addition can improve in vitro germ cell production from cynomolgus monkey ESCs (cyESCs). After 8 days of differentiation, LIF added culture induced dome-shaped germ cell colonies as indicated by the intense expression of alkaline phosphatase activity (ALP). These cells also demonstrate high-level expression of the germ cell-marker VASA, OCT-4, and BLIMP-1, and show SSEA-1 expression that supports their early stage germ cell identity. Finally, we observed that adding LIF to differentiating cultures inhibited meiotic gene expressions and increased the percentage of ALP-positive cells, and demonstrate that the addition of LIF to differentiation media increases differentiation of early germ cells from the cyESCs.
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Affiliation(s)
- Naoto Fukunaga
- Department of Biology Oriented Science and Technology, Kinki University, Osaka, Japan
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9
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Abstract
Evolutionary theory predicts that aging-related fertility declines result from tradeoffs between reproduction and somatic maintenance. Developmental programs for oogenesis also contribute to variation in aging-related reproductive declines among female vertebrates. Documented reproductive aging patterns in female vertebrates, including humans, are consistent with canonical aging patterns determined developmentally and require no special adaptive explanation. Here we discuss patterns of aging-related ovarian decline in diverse female vertebrates, and place human ovarian aging in comparative context. Depletion of finite oocyte stores accompanied by fertility loss occurs in a variety of nonhuman mammals and vertebrates, including short-lived rodents, birds, and some fishes; moreover, postreproductive lifespans of considerable length clearly are not limited to long-lived, social species with well-developed kin networks. We argue for a more rigorous comparative approach for understanding the evolutionary and developmental bases of ovarian aging in vertebrates with a wider range of aging patterns and social structures.
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Affiliation(s)
- Caleb E Finch
- Ethel Percy Andrus Gerontology Center, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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10
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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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11
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Cinquin O. Purpose and regulation of stem cells: a systems-biology view from the Caenorhabditis elegans germ line. J Pathol 2009; 217:186-98. [PMID: 19065622 PMCID: PMC2929242 DOI: 10.1002/path.2481] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Stem cells are expected to play a key role in the development and maintenance of organisms, and hold great therapeutic promises. However, a number of questions must be answered to achieve an understanding of stem cells and put them to use. Here I review some of these questions, and how they relate to the model system provided by the Caenorhabditis elegans germ line, which is exceptional in its thorough genetic characterization and experimental accessibility under in vivo conditions. A fundamental question is how to define a stem cell; different definitions can be adopted that capture different features of interest. In the C. elegans germ line, stem cells can be defined by cell lineage or by cell commitment ('commitment' must itself be carefully defined). These definitions are associated with two other important questions about stem cells: their functions (which must be addressed following a systems approach, based on an evolutionary perspective) and their regulation. I review possible functions and their evolutionary groundings, including genome maintenance and powerful regulation of cell proliferation and differentiation, and possible regulatory mechanisms, including asymmetrical division and control of transit amplification by a developmental timer. I draw parallels between Drosophila and C. elegans germline stem cells; such parallels raise intriguing questions about Drosophila stem cells. I conclude by showing that the C. elegans germ line bears similarities with a number of other stem cell systems, which underscores its relevance to the understanding of stem cells.
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Affiliation(s)
- Olivier Cinquin
- Howard Hughes Medical Institute and Department of Biochemistry, University of Wisconsin-Madison, WI 53706, USA.
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12
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KAKEGAWA R, TERAMURA T, TAKEHARA T, ANZAI M, MITANI T, MATSUMOTO K, SAEKI K, SAGAWA N, FUKUDA K, HOSOI Y. Isolation and Culture of Rabbit Primordial Germ Cells. J Reprod Dev 2008; 54:352-7. [DOI: 10.1262/jrd.20020] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Ryo KAKEGAWA
- Graduate School of Biology-Oriented Science and Technology, Kinki University
| | - Takeshi TERAMURA
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Mie University
- Institute of Advanced Clinical Medicine, Kinki University School of Medicine
| | - Toshiyuki TAKEHARA
- Graduate School of Biology-Oriented Science and Technology, Kinki University
| | | | | | - Kazuya MATSUMOTO
- Graduate School of Biology-Oriented Science and Technology, Kinki University
| | - Kazuhiro SAEKI
- Graduate School of Biology-Oriented Science and Technology, Kinki University
| | - Norimasa SAGAWA
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Mie University
| | - Kanji FUKUDA
- Institute of Advanced Clinical Medicine, Kinki University School of Medicine
- Department of Orthopaedic Surgery, Kinki University School of Medicine
| | - Yoshihiko HOSOI
- Graduate School of Biology-Oriented Science and Technology, Kinki University
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13
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Abstract
Although mammalian sex is determined genetically, the sex-specific development of germ cells as sperm or oocytes is initiated by cues provided by the gonadal environment. During embryogenesis, germ cells in an ovary enter meiosis, thereby committing to oogenesis. By contrast, germ cells in a testicular environment do not enter meiosis until puberty. Recent findings indicate that the key to this sex-specific timing of meiosis entry is the presence or absence of the signaling molecule retinoic acid. Although this knowledge clarifies a long-standing mystery in reproductive biology, it also poses many new questions, which we discuss in this review.
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Affiliation(s)
- Josephine Bowles
- Division of Molecular Genetics and Development, and ARC Centre of Excellence in Biotechnology and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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14
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Mackay S, Smith RA. Effects of growth factors on testicular morphogenesis. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 260:113-73. [PMID: 17482905 DOI: 10.1016/s0074-7696(06)60003-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Since the discovery of the sex-determining gene Sry in 1990, research effort has focused on the events downstream of its expression. A range of different experimental approaches including gene expression, knocking-out and knocking-in genes of interest, and cell and tissue culture techniques have been applied, highlighting the importance of growth factors at all stages of testicular morphogenesis. Migration of primordial germ cells and the mesonephric precursors of peritubular myoid cells and endothelial cells to the gonad is under growth factor control. Proliferation of both germ cells and somatic cells within the gonadal primordium is also controlled by cytokines as is the interaction of Sertoli cells (with each other and with the extracellular matrix) to form testicular cords. Several growth factors/growth factor families (e.g., platelet-derived growth factor, fibroblast growth factor family, TGFbeta family, and neurotrophins) have emerged as key players, exerting an influence at different time points and steps in organogenesis. Although most evidence has emerged in the mouse, comparative studies are important in elucidating the variety, potential, and evolution of control mechanisms.
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Affiliation(s)
- Sarah Mackay
- Division of Neuroscience and Biomedical Systems, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK, G12 8QQ
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15
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Maatouk DM, Kellam LD, Mann MRW, Lei H, Li E, Bartolomei MS, Resnick JL. DNA methylation is a primary mechanism for silencing postmigratory primordial germ cell genes in both germ cell and somatic cell lineages. Development 2006; 133:3411-8. [PMID: 16887828 DOI: 10.1242/dev.02500] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
DNA methylation is necessary for the silencing of endogenous retrotransposons and the maintenance of monoallelic gene expression at imprinted loci and on the X chromosome. Dynamic changes in DNA methylation occur during the initial stages of primordial germ cell development; however, all consequences of this epigenetic reprogramming are not understood. DNA demethylation in postmigratory primordial germ cells coincides with erasure of genomic imprints and reactivation of the inactive X chromosome, as well as ongoing germ cell differentiation events. To investigate a possible role for DNA methylation changes in germ cell differentiation, we have studied several marker genes that initiate expression at this time. Here, we show that the postmigratory germ cell-specific genes Mvh, Dazl and Scp3 are demethylated in germ cells, but not in somatic cells. Premature loss of genomic methylation in Dnmt1 mutant embryos leads to early expression of these genes as well as GCNA1, a widely used germ cell marker. In addition, GCNA1 is ectopically expressed by somatic cells in Dnmt1 mutants. These results provide in vivo evidence that postmigratory germ cell-specific genes are silenced by DNA methylation in both premigratory germ cells and somatic cells. This is the first example of ectopic gene activation in Dnmt1 mutant mice and suggests that dynamic changes in DNA methylation regulate tissue-specific gene expression of a set of primordial germ cell-specific genes.
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Affiliation(s)
- Danielle M Maatouk
- Department of Molecular Genetics and Microbiology, PO Box 100266, University of Florida, Gainesville, FL 32610-0266, USA
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16
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Sakai Y, Noce T, Yamashina S. Cleavage-like cell division and explosive increase in cell number of neonatal gonocytes. Dev Growth Differ 2004; 46:15-21. [PMID: 15008851 DOI: 10.1111/j.1440-169x.2004.00724.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Based on previous conventional quantitative observations of rat testes, it was proposed that large numbers of gonocytes degenerate after birth and this notion was widely accepted. However, many studies show that neonatal gonocytes display high levels of mitotic activity. In order to resolve the apparent contradiction of increased mitotic activity in gonocytes despite a decrease in their numbers at the neonate stage, quantitative analysis using a marker of suitably higher resolution is required. It has been shown that the vasa protein could be used as a marker of germ cells. In this study, quantitative changes in gonocytes were re-examined using a germ-cell-specific marker in order to delineate more clearly the process of development from gonocytes to spermatogonia after birth. The vasa-positive cells, which correspond to gonocytes and spermatogonia, increased exponentially after birth. This observation suggests that all gonocyte divide actively after birth and do not degenerate as previously believed. Surprisingly, the cell volume of gonocytes decreased during their division. The largest population size was 2000-4000 micro3 at day 2, 1000-2000 micro3 at day 4 and 500-1000 micro3 at day 6. This finding suggests that gonocytes divide in a similar way to cleavage, which can be considered a special mode of fertilized eggs. Judging from the growth of seminiferous tubules and the degree of volume reduction, 60% of the contribution rate is estimated to be due to ordinal cell growth, and 40% due to volume reduction as in cleavage of a fertilized egg. This unique cleavage-like division may contribute to the supply of large numbers of spermatogonia.
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Affiliation(s)
- Yasuhiro Sakai
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara 228-8555, Japan.
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17
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Bullejos M, Koopman P. Germ cells enter meiosis in a rostro-caudal wave during development of the mouse ovary. Mol Reprod Dev 2004; 68:422-8. [PMID: 15236325 DOI: 10.1002/mrd.20105] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Germ cells in the mouse embryo remain undifferentiated until about 13.5 days post-coitum (dpc), when male germ cells enter mitotic arrest and female germ cells enter meiosis. The molecular signals and transcriptional control mechanisms governing the differential fate of germ cells in males and females remain largely unknown. In order to gain insights into the behavior of germ cells around this period and into likely mechanisms controlling entry into meiosis, we have studied by wholemount in situ hybridization the expression pattern of two germ cell-specific markers, Oct4 and Sycp3, during mouse fetal gonad development. We observed a dynamic wave of expression of both genes in developing ovaries, with Oct4 expression being extinguished in a rostro-caudal wave and Sycp3 being upregulated in a corresponding wave, during the period 13.5-15.5 dpc. These results indicate that entry into meiosis proceeds in a rostro-caudal progression, in turn suggesting that somatically derived signals may contribute to the control of germ cell entry into meiosis in developing ovaries.
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Affiliation(s)
- Monica Bullejos
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
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18
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Affiliation(s)
- Anne McLaren
- The Wellcome Trust/Cancer Research UK Institute of Cancer and Developmental Biology, Tennis Court Road, Cambridge CB2 1QR, UK.
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19
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Maatouk DM, Resnick JL. Continuing primordial germ cell differentiation in the mouse embryo is a cell-intrinsic program sensitive to DNA methylation. Dev Biol 2003; 258:201-8. [PMID: 12781693 DOI: 10.1016/s0012-1606(03)00110-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The initial cohort of mammalian gametes is established by the proliferation of primordial germ cells in the early embryo. Primordial germ cells first appear in extraembyronic tissues and subsequently migrate to the developing gonad. Soon after they arrive in the gonad, the germ cells cease dividing and undertake sexually dimorphic patterns of development. Male germ cells arrest mitotically, while female germ cells directly enter meiotic prophase I. These sex-specific differentiation events are imposed upon a group of sex-common differentiation events that are shared by XX and XY germ cells. We have studied the appearance of GCNA1, a postmigratory sex-common germ cell marker, in cultures of premigratory germ cells to investigate how this differentiation program is regulated. Cultures in which proliferation was either inhibited or stimulated displayed a similar extent of differentiation as controls, suggesting that some differentiation events are the result of a cell-intrinsic program and are independent of cell proliferation. We also found that GCNA1 expression was accelerated by agents which promote DNA demethylation or histone acetylation. These results suggest that genomic demethylation of proliferative phase primordial germ cells is a mechanism by which germ cell maturation is coordinated.
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Affiliation(s)
- Danielle M Maatouk
- Department of Molecular Genetics and Microbiology, University of Florida, P.O. Box 10266, Gainesville, FL 32610-0266, USA
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20
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Takabayashi S, Sasaoka Y, Yamashita M, Tokumoto T, Ishikawa K, Noguchi M. Novel growth factor supporting survival of murine primordial germ cells: evidence from conditioned medium of ter fetal gonadal somatic cells. Mol Reprod Dev 2001; 60:384-96. [PMID: 11599050 DOI: 10.1002/mrd.1101] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ter (teratoma, chromosome 18) mutation causes a deficiency of primordial germ cells (PGCs) in ter/ter embryos from the ter congenic mouse strain at 8.0 days post coitum (dpc). In order to analyse the function of the ter gene, here we examined effects of conditioned medium (CM) from 14.5 dpc testicular and ovarian somatic cells of +/+, +/ter, or ter/ter genotype on mouse PGCs "mixed-cultured" with own somatic cells on feeder cells. The results showed that +/+ and +/ter CM supported survival in 9.5 and 11.5 dpc ICR PGCs but ter/ter CM did not rescue TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling)-positive apoptosis in the PGCs though it did not affect 5-bromo-2-deoxyuridine incorporation in PGCs. This supportive substance in +/+ CM, not ter/ter CM, was characterized as soluble, heat labile, and larger than 30 kDa. We also found that several known growth factors for PGCs and their receptors were expressed in ter/ter testes as well as +/+ testes, suggesting the ter function is independent. Thus, it was concluded that fetal gonadal somatic cells express a novel PGC growth factor (designated as TER Factor) supporting survival of PGCs not somatic cells and that the PGC deficiency in ter/ter testes is caused by a loss of this factor.
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Affiliation(s)
- S Takabayashi
- Department of Biology and Geosciences, Faculty of Science, Shizuoka University, Ohya 836, Shizuoka 422-8529, Japan
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21
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Takabayashi S, Nozaki M, Ishikawa K, Noguchi M. Theter/terGonadal Somatic Cells Cause Apoptosis inter/terPrimordial Germ Cells (PGCs) with Normal Survivability and Proliferation Ability in the Mouse: Evidence from PGC-Somatic Cell “Exchange-Co-Culture”. Zoolog Sci 2001. [DOI: 10.2108/zsj.18.695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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Chuma S, Nakatsuji N. Autonomous transition into meiosis of mouse fetal germ cells in vitro and its inhibition by gp130-mediated signaling. Dev Biol 2001; 229:468-79. [PMID: 11203703 DOI: 10.1006/dbio.2000.9989] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mouse primordial germ cells (PGCs) arrive at the urogenital ridge (UGR) at around 10.5 days postcoitum (dpc). They proliferate until around 13.5 dpc, then enter into meiosis in the female or become mitotically arrested in the male gonads. In this study, meiotic transition of mouse PGCs was examined in vitro. Female PGCs obtained from UGRs or genital ridges at 10.5-11.5 dpc began to express meiosis-specific genes, Scp3 and Dmc1, after dissociation and cultivation on feeder cells for several days. Meiotic transition into the leptotene stage was confirmed by the formation of axial cores. Male PGCs at 10.5-11.5 dpc and migratory PGCs obtained from mesenteries at 10.5 dpc also expressed Scp3 and formed axial cores after several days of culture, supporting the hypothesis that PGCs are capable of entering meiosis before arriving at the UGR. gp130-mediated signaling, known to promote survival/growth of PGCs and also to inhibit the differentiation of embryonic stem cells, suppressed the expression of Scp3 in PGCs and inhibited the following formation of axial cores in vitro. This novel activity of gp130-mediated signaling may provide some clues for the understanding of pluripotency of mammalian germ-line cells and/or the sex differentiation of fetal germ cells.
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Affiliation(s)
- S Chuma
- Mammalian Development Laboratory, National Institute of Genetics, Mishima, Japan
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23
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Nagano R, Tabata S, Nakanishi Y, Ohsako S, Kurohmaru M, Hayashi Y. Reproliferation and relocation of mouse male germ cells (gonocytes) during prespermatogenesis. THE ANATOMICAL RECORD 2000; 258:210-20. [PMID: 10645968 DOI: 10.1002/(sici)1097-0185(20000201)258:2<210::aid-ar10>3.0.co;2-x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the prespermatogenesis period, male germ cells (gonocytes) begin to reproliferate and move to the basement membrane of the seminiferous tubule. Although these two events-reproliferation and relocation-are important for establishment of spermatogenesis, they have not been greatly analyzed both in a mechanical and in an endocrine or paracrine aspect. In this study, the relationship between reproliferation and relocation of gonocytes was examined, using the thymidine analog bromodeoxyuridine (BrdU) labeling method and transmission electron microscopy (TEM). BrdU was injected into the fetuses [day 13.5 post coitus (dpc) to 18.5 dpc] and pups [day 0. 5 post partum (dpp) to 6.5 dpp] of C57BL/6J mice. Two hours later, BrdU positive gonocytes were examined immunohistochemically and these data were analyzed. TEM and LM observation was carried out as well. Gonocytes began to relocate on the basement membrane from 18.5 dpc (1.4%) while BrdU-labeled gonocytes were first detected on 1.5 dpp (13.6%). Relocated BrdU-negative gonocytes were recognized from 18.5 dpc (1.4%), and relocated BrdU-labeled gonocytes were recognized from 1.5 dpp (8.4%). On the other hand, non-relocated BrdU-labeled gonocytes were detected from 1.5 dpp (5.2%). Gonocyte relocation began 2 days earlier than reproliferation during the late fetal period. After birth, the two events occurred at random. These results indicate that the reproliferation of the gonocyte does not correlate with relocation. The two events may be regulated by different mechanisms.
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Affiliation(s)
- R Nagano
- Department of Veterinary Anatomy, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
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24
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Richards AJ, Enders GC, Resnick JL. Differentiation of murine premigratory primordial germ cells in culture. Biol Reprod 1999; 61:1146-51. [PMID: 10491656 DOI: 10.1095/biolreprod61.4.1146] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In the mouse embryo, primordial germ cells first appear in the extraembryonic mesoderm and divide rapidly while migrating to the fetal gonad. Shortly after their arrival in the gonad, germ cells sexually differentiate as proliferation ceases. Previous studies have established that primordial germ cells proliferate and migrate in feeder layer culture. To explore cellular regulation of fetal germ cell development, we have used germ cell nuclear antigen 1 (GCNA1), a marker normally expressed only in postmigratory germ cells, to investigate the developmental potency of both pre- and postmigratory cells in this culture system. We found that explanted premigratory germ cells will initiate expression of this marker and are, therefore, capable of undertaking some aspects of gonocyte differentiation without intimate exposure to the fetal gonad. We have also tested whether postmigratory gonocytes are stable in culture. As detected by either alkaline phosphatase or GCNA1, we did not detect long-term survival of either prospermatogonia or oogonia under conditions that support the survival, proliferation, and differentiation of earlier premigratory cells. These observations are consistent with an autonomous cellular mechanism governing the initial stages of gonocyte differentiation, and suggest that differentiation towards gonocytes is accompanied by a change in requirements for cell survival.
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Affiliation(s)
- A J Richards
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida 32610-0266, USA
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25
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Abstract
A large number of primordial germ cells (PGCs), as well as spermatogonia, undergo programmed cell death or apoptosis in the physiological context. In this process, environmental, cytoplasmic and nuclear factors are involved. Bcl-2 and its related molecules are known as general regulators of cell death, and some are important for survival of PGCs and spermatogonia. Steel factor, a ligand for c-Kit, also supports growth and survival of these cells. In addition, bone morphogenetic protein (BMP)8B and Desert Hedgehog (Dhh), which are secreted proteins, and a nuclear factor, c-Myc, play a role in spermatocyte survival. This suggests that germ cell survival or death at each stage of differentiation is precisely controlled by specific signalling pathways which consist of a number of molecules.
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Affiliation(s)
- Y Matsui
- Department of Cell Biology, Tohoku University, Japan
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26
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Rajpert-De Meyts E, Jørgensen N, Brøndum-Nielsen K, Müller J, Skakkebaek NE. Developmental arrest of germ cells in the pathogenesis of germ cell neoplasia. APMIS 1998; 106:198-204; discussion 204-6. [PMID: 9524579 DOI: 10.1111/j.1699-0463.1998.tb01336.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Clinical observations and epidemiological evidence suggest that important aetiopathological events that cause neoplastic transformation of the male germ cell may occur in fetal life or early infancy. The incidence of germ cell neoplasia is high in individuals with various disorders of gonadal development and sexual differentiation, such as gonadal dysgenesis or androgen insensitivity syndrome. Increased risk has also been noted in individuals with trisomy 21, idiopathic infertility and low birth weight. Infertility is sometimes associated with small aberrations of sex chromosomes (e.g. low frequency mosaicism XY/XO) which can also be found in patients with testicular cancer. The variety of conditions that predispose to testicular neoplasia and the rise in its incidence in many countries speaks for the influence of environmental factors which may affect genetically predisposed individuals. We hypothesise that if the development of the testis is disturbed or delayed, primordial germ cells or gonocytes undergo maturation delay or differentiation arrest which may render them susceptible to neoplastic transformation. Morphologically homogenous premalignant carcinoma in situ (CIS) cells have the potential to differentiate into a variety of histological forms of overt testicular tumours. Analysis of cell surface antigens expressed by CIS cells found in the vicinity of pure and mixed tumours demonstrates that CIS cells are phenotypically heterogeneous. Comparison of the phenotypes of CIS cells, primordial germ cells, human embryonal carcinoma cells and closely related primate embryonal stem cells reveals various similarities but also differences. We speculate that phenotypical heterogeneity of CIS cells may be associated with their potential to give rise to different tumour types, and may be related to the developmental stage of the early germ cell which has undergone malignant transformation.
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Affiliation(s)
- E Rajpert-De Meyts
- Department of Growth and Reproduction, Copenhagen University and Rigshospitalet, Denmark
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27
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Abstract
Germ cells harvested from mouse embryonic genital ridges were mixed with disaggregated embryonic lung cells, and the reaggregates were cultured for 4-7 days. Germ cells derived from female embryos 10.5-13.5 days postcoitum (dpc) entered and progressed through meiotic prophase in vitro as in vivo, although with a 12- to 24-hr delay. If the cultures were maintained for 2-3 weeks, the germ cells developed into growing oocytes. When germ cells were taken from male embryos 10.5 and 11.5 dpc, they too entered and progressed through meiotic prophase, but germ cells from later embryos (12.5 and 13.5 dpc) developed as prospermatogonia, as in male genital ridges in vivo. When 11.5 dpc male genital ridges were disaggregated, reaggregated, and cultured in the same way as the lung reaggregates, the germ cells again entered meiotic prophase. We conclude that the male genital ridge at about 12 dpc produces a factor that inhibits entry of germ cells into meiosis, and that production of this factor is disrupted by prior disaggregation of the genital ridge. If a meiotic inducing substance is required for entry of germ cells into meiosis, it must be present in the male genital ridge as well as in the female genital ridge, and probably also in the lung.
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Affiliation(s)
- A McLaren
- Wellcome/CRC Institute, Cambridge, United Kingdom
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28
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Abstract
Monoclonal antibodies anti-SSEA-1 and EMA-1, and the lectins DBA and LTA, bound to the surface of large, round cells randomly distributed in the 26-day pig genital ridge. Other antibodies, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81, did not react with any cells in the pig genital ridge. SSEA-1-positive cells displayed pseudopods and appeared to migrate from the dorsal mesentery of the hindgut (18-day) to the primordium of the gonad (day 23) and entered the genital ridge by 26 days. The number of SSEA-1-positive cells associated with the dorsal mesentery and genital ridge markedly increased from the 18-day to the 26-day pig embryo. It was concluded that the SSEA-1-positive cells were primordial germ cells (PGCs). Using these markers and alkaline phosphatase histochemistry, pig PGCs derived from the 26-day genital ridge showed no proliferation when grown in STO co-culture in the presence of human LIF, bFGF and SCF.
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Affiliation(s)
- Y Takagi
- Faculty of Agriculture, Shinshu University, Minamiminowa, Nagano, Japan
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