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Sample records for germ cells pgcs

  1. Effect of microgravity on primordial germ cells (PGCs) in silk chicken offspring ( Gallus gallus domesticus)

    NASA Astrophysics Data System (ADS)

    Zhou, Zhenming; Li, Zandong

    2011-08-01

    Primordial germ cells (PGCs), precursors of germline cells, display a variety of antigens during their migration to target gonads. Here, we used silk chicken offspring ( Gallus gallus domesticus) embryos subjected to space microgravity to investigate the influence of microgravity on PGCs. The ShenZhou-3 unmanned spaceship carried nine fertilized silk chicken eggs, named the flight group, returned to Earth after 7 days space flight. And the control group has the same clan with the flight group. PGCs from flight and control group silk chicken offspring embryos were examined during migration by using two antibodies (2C9 and anti-SSEA-1), in combination with the horseradish peroxidase detection system, and using periodic acid-Schiff's solution (PAS) reaction. After incubation for about 30 h, SSEA-1 and 2C9 positive cells were detected in the germinal crescent of flight and control group silk chicken offspring embryos. After incubation of eggs for 2-2.5 days, SSEA-1 and 2C9 positive cells were detected in embryonic blood vessels of flight and control group silk chicken offspring embryos. After incubation of eggs for 5.5 days, PGCs in the dorsal mesentery and gonad could also be identified in flight and control group silk chicken offspring embryos by using SSEA-1 and 2C9 antibodies. Based on location and PAS staining, these cells were identified as PGCs. Meanwhile, at the stage of PGCs migration and then becoming established in the germinal ridges, no difference in SSEA-1 or 2C9 staining was detected between female and male PGCs in flight and control group silk chicken offspring embryos. Although there were differences in the profiles of PGC concentration between male and female embryos during the special circulating stage, changing profile of PGCs concentration was similar in same sex between flight and control group offspring embryos. We concluded that there is little effect on PGCs in offspring embryos of microgravity-treated chicken and that PGC development appears

  2. Reprogramming of germ cells into pluripotency

    PubMed Central

    Sekita, Yoichi; Nakamura, Toshinobu; Kimura, Tohru

    2016-01-01

    Primordial germ cells (PGCs) are precursors of all gametes, and represent the founder cells of the germline. Although developmental potency is restricted to germ-lineage cells, PGCs can be reprogrammed into a pluripotent state. Specifically, PGCs give rise to germ cell tumors, such as testicular teratomas, in vivo, and to pluripotent stem cells known as embryonic germ cells in vitro. In this review, we highlight the current knowledge on signaling pathways, transcriptional controls, and post-transcriptional controls that govern germ cell differentiation and de-differentiation. These regulatory processes are common in the reprogramming of germ cells and somatic cells, and play a role in the pathogenesis of human germ cell tumors. PMID:27621759

  3. Reprogramming of germ cells into pluripotency.

    PubMed

    Sekita, Yoichi; Nakamura, Toshinobu; Kimura, Tohru

    2016-08-26

    Primordial germ cells (PGCs) are precursors of all gametes, and represent the founder cells of the germline. Although developmental potency is restricted to germ-lineage cells, PGCs can be reprogrammed into a pluripotent state. Specifically, PGCs give rise to germ cell tumors, such as testicular teratomas, in vivo, and to pluripotent stem cells known as embryonic germ cells in vitro. In this review, we highlight the current knowledge on signaling pathways, transcriptional controls, and post-transcriptional controls that govern germ cell differentiation and de-differentiation. These regulatory processes are common in the reprogramming of germ cells and somatic cells, and play a role in the pathogenesis of human germ cell tumors. PMID:27621759

  4. dead end, a novel vertebrate germ plasm component, is required for zebrafish primordial germ cell migration and survival.

    PubMed

    Weidinger, Gilbert; Stebler, Jürg; Slanchev, Krasimir; Dumstrei, Karin; Wise, Clare; Lovell-Badge, Robin; Thisse, Christine; Thisse, Bernard; Raz, Erez

    2003-08-19

    In most animals, primordial germ cell (PGC) specification and development depend on maternally provided cytoplasmic determinants that constitute the so-called germ plasm. Little is known about the role of germ plasm in vertebrate germ cell development, and its molecular mode of action remains elusive. While PGC specification in mammals occurs via different mechanisms, several germ plasm components required for early PGC development in lower organisms are expressed in mammalian germ cells after their migration to the gonad and are involved in gametogenesis. Here we show that the RNA of dead end, encoding a novel putative RNA binding protein, is a component of the germ plasm in zebrafish and is specifically expressed in PGCs throughout embryogenesis; Dead End protein is localized to perinuclear germ granules within PGCs. Knockdown of dead end blocks confinement of PGCs to the deep blastoderm shortly after their specification and results in failure of PGCs to exhibit motile behavior and to actively migrate thereafter. PGCs subsequently die, while somatic development is not effected. We have identified dead end orthologs in other vertebrates including Xenopus, mouse, and chick, where they are expressed in germ plasm and germ-line cells, suggesting a role in germ-line development in these organisms as well. PMID:12932328

  5. Analysis of chicken primordial germ cells

    PubMed Central

    Motono, Makoto; Ohashi, Takuya; Iijima, Shinji

    2008-01-01

    Primordial germ cells (PGCs) are precursors of germline cells. Although avian PGCs have been used to produce transgenic birds, their characteristics largely remain unknown. In this study, we isolated PGCs from chicken embryos at various developmental stages and analyzed the gene expression. Using the expression of stage-specific embryonic antigen-1 (SSEA-1) as a marker of chicken PGCs, we purified PGCs from embryos by fluorescence-activated cell sorting after incubation for 2.5–8.5 days. The number of SSEA-1+ cells was almost unchanged during days 2.5–8.5 of incubation in females but continuously increased in male. Expression of several genes, including Blimp1, SOX2, and CXCR4, was observed in SSEA-1+ cells but not in SSEA-1− cells in both female and male embryos. Quantitative reverse-transcription PCR analysis revealed that the expression of CXCR4, a chemokine receptor essential for migration of PGCs from the bloodstream to the gonads, was reduced after the circulating PGC stage (day 2.5). PMID:19003166

  6. Cholesterol induces proliferation of chicken primordial germ cells.

    PubMed

    Chen, Dongyang; Chen, Meijuan; Lu, Zhenping; Yang, Mengmeng; Xie, Long; Zhang, Wenxin; Xu, Huiyan; Lu, Kehuan; Lu, Yangqing

    2016-08-01

    Primordial germ cells (PGCs) are the precursors of sperm and eggs and may serve as suitable cells for use in research in developmental biology and transgenic animals. However, the long-term propagation of PGCs in vitro has so far been plagued by the loss of their germ cell characteristics. This is largely because of the scarcity of knowledge concerning cell division and proliferation in these cells and the poor optimization of the culture medium. The sonic hedgehog (SHH) signaling pathway is involved in proliferation of many types of cells, but little is known about its role in chicken PGCs. The results of the current study indicate that the proliferation of chicken PGCs increases significantly when cholesterol, a molecule that facilitates the trafficking of HH ligands, is supplemented in the culture medium. This effect was attenuated when an SHH antagonist, cyclopamine was added, suggesting the involvement of SHH signaling in this process. The characterization of PGCs treated with cholesterol has shown that these cells express germ-cell-related markers and retain their capability to colonize the embryonic gonad after re-introduction to vasculature of stage-15 HH embryos, indicating that proliferation of PGCs induced by cholesterol does not alter the germ cell characteristics of these cells. PMID:27269880

  7. Two-step oligoclonal development of male germ cells.

    PubMed

    Ueno, Hiroo; Turnbull, Brit B; Weissman, Irving L

    2009-01-01

    During mouse development, primordial germ cells (PGCs) that give rise to the entire germ line are first identified within the proximal epiblast. However, long-term tracing of the fate of the cells has not been done wherein all cells in and around the germ-cell lineage are identified. Also, quantitative estimates of the number of founder PGCs using different models have come up with various numbers. Here, we use tetrachimeric mice to show that the progenitor numbers for the entire germ line in adult testis, and for the initiating embryonic PGCs, are both 4 cells. Although they proliferate to form polyclonal germ-cell populations in fetal and neonatal testes, germ cells that actually contribute to adult spermatogenesis originate from a small number of secondary founder cells that originate in the fetal period. The rest of the "deciduous" germ cells are lost, most likely by apoptosis, before the reproductive period. The second "actual" founder germ cells generally form small numbers of large monoclonal areas in testes by the reproductive period. Our results also demonstrate that there is no contribution of somatic cells to the male germ cell pool during development or in adulthood. These results suggest a model of 2-step oligoclonal development of male germ cells in mice, the second step distinguishing the heritable germ line from cells selected not to participate in forming the next generation. PMID:19098099

  8. Specification of germ cell fate in mice.

    PubMed Central

    Saitou, Mitinori; Payer, Bernhard; Lange, Ulrike C; Erhardt, Sylvia; Barton, Sheila C; Surani, M Azim

    2003-01-01

    An early fundamental event during development is the segregation of germ cells from somatic cells. In many organisms, this is accomplished by the inheritance of preformed germ plasm, which apparently imposes transcriptional repression to prevent somatic cell fate. However, in mammals, pluripotent epiblast cells acquire germ cell fate in response to signalling molecules. We have used single cell analysis to study how epiblast cells acquire germ cell competence and undergo specification. Germ cell competent cells express Fragilis and initially progress towards a somatic mesodermal fate. However, a subset of these cells, the future primordial germ cells (PGCs), then shows rapid upregulation of Fragilis with concomitant transcriptional repression of a number of genes, including Hox and Smad genes. This repression may be a key event associated with germ cell specification. Furthermore, PGCs express Stella and other genes, such as Oct-4 that are associated with pluripotency. While these molecules are also detected in mature oocytes as maternally inherited factors, their early role is to regulate development and maintain pluripotency, and they do not serve the role of classical germline determinants. PMID:14511483

  9. Development without germ cells: the role of the germ line in zebrafish sex differentiation.

    PubMed

    Slanchev, Krasimir; Stebler, Jürg; de la Cueva-Méndez, Guillermo; Raz, Erez

    2005-03-15

    The progenitors of the gametes, the primordial germ cells (PGCs) are typically specified early in the development in positions, which are distinct from the gonad. These cells then migrate toward the gonad where they differentiate into sperms and eggs. Here, we study the role of the germ cells in somatic development and particularly the role of the germ line in the sex differentiation in zebrafish. To this end, we ablated the germ cells using two independent methods and followed the development of the experimental fish. First, PGCs were ablated by knocking down the function of dead end, a gene important for the survival of this lineage. Second, a method to eliminate the PGCs using the toxin-antitoxin components of the parD bacterial genetic system was used. Specifically, we expressed a bacterial toxin Kid preferentially in the PGCs and at the same time protected somatic cells by uniformly expressing the specific antidote Kis. Our results demonstrate an unexpected role for the germ line in promoting female development because PGC-ablated fish invariably developed as males. PMID:15728735

  10. Development without germ cells: The role of the germ line in zebrafish sex differentiation

    PubMed Central

    Slanchev, Krasimir; Stebler, Jürg; de la Cueva-Méndez, Guillermo; Raz, Erez

    2005-01-01

    The progenitors of the gametes, the primordial germ cells (PGCs) are typically specified early in the development in positions, which are distinct from the gonad. These cells then migrate toward the gonad where they differentiate into sperms and eggs. Here, we study the role of the germ cells in somatic development and particularly the role of the germ line in the sex differentiation in zebrafish. To this end, we ablated the germ cells using two independent methods and followed the development of the experimental fish. First, PGCs were ablated by knocking down the function of dead end, a gene important for the survival of this lineage. Second, a method to eliminate the PGCs using the toxin–antitoxin components of the parD bacterial genetic system was used. Specifically, we expressed a bacterial toxin Kid preferentially in the PGCs and at the same time protected somatic cells by uniformly expressing the specific antidote Kis. Our results demonstrate an unexpected role for the germ line in promoting female development because PGC-ablated fish invariably developed as males. PMID:15728735

  11. The majority of early primordial germ cells acquire pluripotency by AKT activation.

    PubMed

    Matsui, Yasuhisa; Takehara, Asuka; Tokitake, Yuko; Ikeda, Makiko; Obara, Yuka; Morita-Fujimura, Yuiko; Kimura, Tohru; Nakano, Toru

    2014-12-01

    Primordial germ cells (PGCs) are undifferentiated germ cells in embryos, the fate of which is to become gametes; however, mouse PGCs can easily be reprogrammed into pluripotent embryonic germ cells (EGCs) in culture in the presence of particular extracellular factors, such as combinations of Steel factor (KITL), LIF and bFGF (FGF2). Early PGCs form EGCs more readily than do later PGCs, and PGCs lose the ability to form EGCs by embryonic day (E) 15.5. Here, we examined the effects of activation of the serine/threonine kinase AKT in PGCs during EGC formation; notably, AKT activation, in combination with LIF and bFGF, enhanced EGC formation and caused ∼60% of E10.5 PGCs to become EGCs. The results indicate that the majority of PGCs at E10.5 could acquire pluripotency with an activated AKT signaling pathway. Importantly, AKT activation did not fully substitute for bFGF and LIF, and AKT activation without both LIF and bFGF did not result in EGC formation. These findings indicate that AKT signal enhances and/or collaborates with signaling pathways of bFGF and of LIF in PGCs for the acquisition of pluripotency. PMID:25359722

  12. Rebuilding Pluripotency from Primordial Germ Cells

    PubMed Central

    Leitch, Harry G.; Nichols, Jennifer; Humphreys, Peter; Mulas, Carla; Martello, Graziano; Lee, Caroline; Jones, Ken; Surani, M. Azim; Smith, Austin

    2013-01-01

    Mammalian primordial germ cells (PGCs) are unipotent progenitors of the gametes. Nonetheless, they can give rise directly to pluripotent stem cells in vitro or during teratocarcinogenesis. This conversion is inconsistent, however, and has been difficult to study. Here, we delineate requirements for efficient resetting of pluripotency in culture. We demonstrate that in defined conditions, routinely 20% of PGCs become EG cells. Conversion can occur from the earliest specified PGCs. The entire process can be tracked from single cells. It is driven by leukemia inhibitory factor (LIF) and the downstream transcription factor STAT3. In contrast, LIF signaling is not required during germ cell ontogeny. We surmise that ectopic LIF/STAT3 stimulation reconstructs latent pluripotency and self-renewal. Notably, STAT3 targets are significantly upregulated in germ cell tumors, suggesting that dysregulation of this pathway may underlie teratocarcinogenesis. These findings demonstrate that EG cell formation is a robust experimental system for exploring mechanisms involved in reprogramming and cancer. PMID:24052943

  13. Specifying and protecting germ cell fate

    PubMed Central

    Strome, Susan; Updike, Dustin

    2015-01-01

    Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied ‘germ plasm’, inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells. PMID:26122616

  14. The Origin And Migration Of Primordial Germ Cells In Sturgeons

    PubMed Central

    Saito, Taiju; Pšenička, Martin; Goto, Rie; Adachi, Shinji; Inoue, Kunio; Arai, Katsutoshi; Yamaha, Etsuro

    2014-01-01

    Primordial germ cells (PGCs) arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser) have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super class Actinoptergii, and their developmental pattern is similar to that of amphibians, although their phylogenetic position is an out-group to teleost fishes. Here, we reveal an injection technique for sturgeon eggs allowing visualization of germplasm and PGCs. Using this technique, we demonstrate that the PGCs are generated at the vegetal pole of the egg and they migrate on the yolky cell mass toward the gonadal ridge. We also provide evidence showing that PGCs are specified by inheritance of maternally supplied germplasm. Furthermore, we demonstrate that the migratory mechanism is well-conserved between sturgeon and other remotely related teleosts, such as goldfish, by a single PGCs transplantation (SPT) assay. The mode of PGCs specification in sturgeon is similar to that of anurans, but the migration pattern resembles that of teleosts. PMID:24505272

  15. PGC-Enriched miRNAs Control Germ Cell Development

    PubMed Central

    Bhin, Jinhyuk; Jeong, Hoe-Su; Kim, Jong Soo; Shin, Jeong Oh; Hong, Ki Sung; Jung, Han-Sung; Kim, Changhoon; Hwang, Daehee; Kim, Kye-Seong

    2015-01-01

    Non-coding microRNAs (miRNAs) regulate the translation of target messenger RNAs (mRNAs) involved in the growth and development of a variety of cells, including primordial germ cells (PGCs) which play an essential role in germ cell development. However, the target mRNAs and the regulatory networks influenced by miRNAs in PGCs remain unclear. Here, we demonstrate a novel miRNAs control PGC development through targeting mRNAs involved in various cellular pathways. We reveal the PGC-enriched expression patterns of nine miRNAs, including miR-10b, -18a, -93, -106b, -126-3p, -127, -181a, -181b, and -301, using miRNA expression analysis along with mRNA microarray analysis in PGCs, embryonic gonads, and postnatal testes. These miRNAs are highly expressed in PGCs, as demonstrated by Northern blotting, miRNA in situ hybridization assay, and miRNA qPCR analysis. This integrative study utilizing mRNA microarray analysis and miRNA target prediction demonstrates the regulatory networks through which these miRNAs regulate their potential target genes during PGC development. The elucidated networks of miRNAs disclose a coordinated molecular mechanism by which these miRNAs regulate distinct cellular pathways in PGCs that determine germ cell development. PMID:26442865

  16. Restricted distribution of mrg-1 mRNA in C. elegans primordial germ cells through germ granule-independent regulation.

    PubMed

    Miwa, Takashi; Takasaki, Teruaki; Inoue, Kunio; Sakamoto, Hiroshi

    2015-11-01

    The chromodomain protein MRG-1 is an essential maternal factor for proper germline development that protects germ cells from cell death in C. elegans. Unlike germ granules, which are exclusively segregated to the germline blastomeres at each cell division from the first cleavage of the embryo, MRG-1 is abundant in all cells in early embryos and is then gradually restricted to the primordial germ cells (PGCs) by the morphogenesis stage. Here, we show that this characteristic spatiotemporal expression pattern is dictated by the mrg-1 3'UTR and is differentially regulated at the RNA level between germline and somatic cells. Asymmetric segregation of germ granules is not necessary to localize MRG-1 to the PGCs. We found that MES-4, an essential chromatin regulator in germ cells, also accumulates in the PGCs in a germ granule-independent manner. We propose that C.elegans PGCs have a novel mechanism to accumulate at least some chromatin-associated proteins that are essential for germline immortality. PMID:26537333

  17. Perspectives of germ cell development in vitro in mammals

    PubMed Central

    Hayashi, Katsuhiko; Saitou, Mitinori

    2014-01-01

    Pluripotent stem cells, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are able to differentiate into all cell lineages of the embryo proper, including germ cells. This pluripotent property has a huge impact on the fields of regenerative medicine, developmental biology and reproductive engineering. Establishing the germ cell lineage from ESCs/iPSCs is the key biological subject, since it would contribute not only to dissection of the biological processes of germ cell development but also to production of unlimited numbers of functional gametes in vitro. Toward this goal, we recently established a culture system that induces functional mouse primordial germ cells (PGCs), precursors of all germ cells, from mouse ESCs/iPSCs. The successful in vitro production of PGCs arose from the study of pluripotent cell state, the signals inducing PGCs and the technology of transplantation. However, there are many obstacles to be overcome for the robust generation of mature gametes or for application of the culture system to other species, including humans and livestock. In this review, we discuss the requirements for a culture system to generate the germ cell lineage from ESCs/iPSCs. PMID:24725251

  18. Dnd Is a Critical Specifier of Primordial Germ Cells in the Medaka Fish.

    PubMed

    Hong, Ni; Li, Mingyou; Yuan, Yongming; Wang, Tiansu; Yi, Meisheng; Xu, Hongyan; Zeng, Huaqiang; Song, Jianxing; Hong, Yunhan

    2016-03-01

    Primordial germ cell (PGC) specification occurs early in development. PGC specifiers have been identified in Drosophila, mouse, and human but remained elusive in most animals. Here we identify the RNA-binding protein Dnd as a critical PGC specifier in the medaka fish (Oryzias latipes). Dnd depletion specifically abolished PGCs, and its overexpression boosted PGCs. We established a single-cell culture procedure enabling lineage tracing in vitro. We show that individual blastomeres from cleavage embryos at the 32- and 64-cell stages are capable of PGC production in culture. Importantly, Dnd overexpression increases PGCs via increasing PGC precursors. Strikingly, dnd RNA forms prominent particles that segregate asymmetrically. Dnd concentrates in germ plasm and stabilizes germ plasm RNA. Therefore, Dnd is a critical specifier of fish PGCs and utilizes particle partition as a previously unidentified mechanism for asymmetric segregation. These findings offer insights into PGC specification and manipulation in medaka as a lower vertebrate model. PMID:26852942

  19. Dnd Is a Critical Specifier of Primordial Germ Cells in the Medaka Fish

    PubMed Central

    Hong, Ni; Li, Mingyou; Yuan, Yongming; Wang, Tiansu; Yi, Meisheng; Xu, Hongyan; Zeng, Huaqiang; Song, Jianxing; Hong, Yunhan

    2016-01-01

    Summary Primordial germ cell (PGC) specification occurs early in development. PGC specifiers have been identified in Drosophila, mouse, and human but remained elusive in most animals. Here we identify the RNA-binding protein Dnd as a critical PGC specifier in the medaka fish (Oryzias latipes). Dnd depletion specifically abolished PGCs, and its overexpression boosted PGCs. We established a single-cell culture procedure enabling lineage tracing in vitro. We show that individual blastomeres from cleavage embryos at the 32- and 64-cell stages are capable of PGC production in culture. Importantly, Dnd overexpression increases PGCs via increasing PGC precursors. Strikingly, dnd RNA forms prominent particles that segregate asymmetrically. Dnd concentrates in germ plasm and stabilizes germ plasm RNA. Therefore, Dnd is a critical specifier of fish PGCs and utilizes particle partition as a previously unidentified mechanism for asymmetric segregation. These findings offer insights into PGC specification and manipulation in medaka as a lower vertebrate model. PMID:26852942

  20. An E-cadherin-mediated hitchhiking mechanism for C. elegans germ cell internalization during gastrulation

    PubMed Central

    Chihara, Daisuke; Nance, Jeremy

    2012-01-01

    Gastrulation movements place endodermal precursors, mesodermal precursors and primordial germ cells (PGCs) into the interior of the embryo. Somatic cell gastrulation movements are regulated by transcription factors that also control cell fate, coupling cell identity and position. By contrast, PGCs in many species are transcriptionally quiescent, suggesting that they might use alternative gastrulation strategies. Here, we show that C. elegans PGCs internalize by attaching to internal endodermal cells, which undergo morphogenetic movements that pull the PGCs into the embryo. We show that PGCs enrich HMR-1/E-cadherin at their surfaces to stick to endoderm. HMR-1 expression in PGCs is necessary and sufficient to ensure internalization, suggesting that HMR-1 can promote PGC-endoderm adhesion through a mechanism other than homotypic trans interactions between the two cell groups. Finally, we demonstrate that the hmr-1 3′ untranslated region promotes increased HMR-1 translation in PGCs. Our findings reveal that quiescent PGCs employ a post-transcriptionally regulated hitchhiking mechanism to internalize during gastrulation, and demonstrate a morphogenetic role for the conserved association of PGCs with the endoderm. PMID:22675206

  1. Differential Expression of Conserved Germ Line Markers and Delayed Segregation of Male and Female Primordial Germ Cells in a Hermaphrodite, the Leech Helobdella

    PubMed Central

    Cho, Sung-Jin; Vallès, Yvonne; Weisblat, David A.

    2014-01-01

    In sexually reproducing animals, primordial germ cells (PGCs) are often set aside early in embryogenesis, a strategy that minimizes the risk of genomic damage associated with replication and mitosis during the cell cycle. Here, we have used germ line markers (piwi, vasa, and nanos) and microinjected cell lineage tracers to show that PGC specification in the leech genus Helobdella follows a different scenario: in this hermaphrodite, the male and female PGCs segregate from somatic lineages only after more than 20 rounds of zygotic mitosis; the male and female PGCs share the same (mesodermal) cell lineage for 19 rounds of zygotic mitosis. Moreover, while all three markers are expressed in both male and female reproductive tissues of the adult, they are expressed differentially between the male and female PGCs of the developing embryo: piwi and vasa are expressed preferentially in female PGCs at a time when nanos is expressed preferentially in male PGCs. A priori, the delayed segregation of male and female PGCs from somatic tissues and from one another increases the probability of mutations affecting both male and female PGCs of a given individual. We speculate that this suite of features, combined with a capacity for self-fertilization, may contribute to the dramatically rearranged genome of Helobdella robusta relative to other animals. PMID:24217283

  2. Metastable primordial germ cell-like state induced from mouse embryonic stem cells by Akt activation

    SciTech Connect

    Yamano, Noriko; Kimura, Tohru; Watanabe-Kushima, Shoko; Shinohara, Takashi; Nakano, Toru

    2010-02-12

    Specification to primordial germ cells (PGCs) is mediated by mesoderm-induction signals during gastrulation. We found that Akt activation during in vitro mesodermal differentiation of embryonic stem cells (ESCs) generated self-renewing spheres with differentiation states between those of ESCs and PGCs. Essential regulators for PGC specification and their downstream germ cell-specific genes were expressed in the spheres, indicating that the sphere cells had commenced differentiation to the germ lineage. However, the spheres did not proceed to spermatogenesis after transplantation into testes. Sphere cell transfer to the original feeder-free ESC cultures resulted in chaotic differentiation. In contrast, when the spheres were cultured on mouse embryonic fibroblasts or in the presence of ERK-cascade and GSK3 inhibitors, reversion to the ESC-like state was observed. These results indicate that Akt signaling promotes a novel metastable and pluripotent state that is intermediate to those of ESCs and PGCs.

  3. Cryopreservation of specialized chicken lines using cultured primordial germ cells.

    PubMed

    Nandi, S; Whyte, J; Taylor, L; Sherman, A; Nair, V; Kaiser, P; McGrew, M J

    2016-08-01

    Biosecurity and sustainability in poultry production requires reliable germplasm conservation. Germplasm conservation in poultry is more challenging in comparison to other livestock species. Embryo cryopreservation is not feasible for egg-laying animals, and chicken semen conservation has variable success for different chicken breeds. A potential solution is the cryopreservation of the committed diploid stem cell precursors to the gametes, the primordial germ cells ( PGCS: ). Primordial germ cells are the lineage-restricted cells found at early embryonic stages in birds and form the sperm and eggs. We demonstrate here, using flocks of partially inbred, lower-fertility, major histocompatibility complex- ( MHC-: ) restricted lines of chicken, that we can easily derive and cryopreserve a sufficient number of independent lines of male and female PGCs that would be sufficient to reconstitute a poultry breed. We demonstrate that germ-line transmission can be attained from these PGCs using a commercial layer line of chickens as a surrogate host. This research is a major step in developing and demonstrating that cryopreserved PGCs could be used for the biobanking of specialized flocks of birds used in research settings. The prospective application of this technology to poultry production will further increase sustainability to meet current and future production needs. PMID:27099306

  4. Cryopreservation of specialized chicken lines using cultured primordial germ cells

    PubMed Central

    Nandi, S.; Whyte, J.; Taylor, L.; Sherman, A.; Nair, V.; Kaiser, P.; McGrew, M. J.

    2016-01-01

    Biosecurity and sustainability in poultry production requires reliable germplasm conservation. Germplasm conservation in poultry is more challenging in comparison to other livestock species. Embryo cryopreservation is not feasible for egg-laying animals, and chicken semen conservation has variable success for different chicken breeds. A potential solution is the cryopreservation of the committed diploid stem cell precursors to the gametes, the primordial germ cells (PGCs). Primordial germ cells are the lineage-restricted cells found at early embryonic stages in birds and form the sperm and eggs. We demonstrate here, using flocks of partially inbred, lower-fertility, major histocompatibility complex- (MHC-) restricted lines of chicken, that we can easily derive and cryopreserve a sufficient number of independent lines of male and female PGCs that would be sufficient to reconstitute a poultry breed. We demonstrate that germ-line transmission can be attained from these PGCs using a commercial layer line of chickens as a surrogate host. This research is a major step in developing and demonstrating that cryopreserved PGCs could be used for the biobanking of specialized flocks of birds used in research settings. The prospective application of this technology to poultry production will further increase sustainability to meet current and future production needs. PMID:27099306

  5. Reproduction of wild birds via interspecies germ cell transplantation.

    PubMed

    Kang, Seok Jin; Choi, Jin Won; Kim, Sun Young; Park, Kyung Je; Kim, Tae Min; Lee, Young Mok; Kim, Heebal; Lim, Jeong Mook; Han, Jae Yong

    2008-11-01

    The present study was conducted to apply an interspecies germ cell transfer technique to wild bird reproduction. Pheasant (Phasianus colchicus) primordial germ cells (PGCs) retrieved from the gonads of 7-day-old embryos were transferred to the bloodstream of 2.5-day-old chicken (Gallus gallus) embryos. Pheasant-to-chicken germline chimeras hatched from the recipient embryos, and 10 pheasants were derived from testcross reproduction of the male chimeras with female pheasants. Gonadal migration of the transferred PGCs, their involvement in spermatogenesis, and production of chimeric semen were confirmed. The phenotype of pheasant progenies derived from the interspecies transfer was identical to that of wild pheasants. The average efficiency of reproduction estimated from the percentage of pheasants to total progenies was 17.5%. In conclusion, interspecies germ cell transfer into a developing embryo can be used for wild bird reproduction, and this reproductive technology may be applicable in conserving endangered bird species. PMID:18685127

  6. In vitro differentiation of germ cells from stem cells: a comparison between primordial germ cells and in vitro derived primordial germ cell-like cells.

    PubMed

    Ge, W; Chen, C; De Felici, M; Shen, W

    2015-01-01

    Stem cells are unique cell types capable to proliferate, some of them indefinitely, while maintaining the ability to differentiate into a few or any cell lineages. In 2003, a group headed by Hans R. Schöler reported that oocyte-like cells could be produced from mouse embryonic stem (ES) cells in vitro. After more than 10 years, where have these researches reached? Which are the major successes achieved and the problems still remaining to be solved? Although during the last years, many reviews have been published about these topics, in the present work, we will focus on an aspect that has been little considered so far, namely a strict comparison between the in vitro and in vivo developmental capabilities of the primordial germ cells (PGCs) isolated from the embryo and the PGC-like cells (PGC-LCs) produced in vitro from different types of stem cells in the mouse, the species in which most investigation has been carried out. Actually, the formation and differentiation of PGCs are crucial for both male and female gametogenesis, and the faithful production of PGCs in vitro represents the basis for obtaining functional germ cells. PMID:26469955

  7. In vitro differentiation of germ cells from stem cells: a comparison between primordial germ cells and in vitro derived primordial germ cell-like cells

    PubMed Central

    Ge, W; Chen, C; De Felici, M; Shen, W

    2015-01-01

    Stem cells are unique cell types capable to proliferate, some of them indefinitely, while maintaining the ability to differentiate into a few or any cell lineages. In 2003, a group headed by Hans R. Schöler reported that oocyte-like cells could be produced from mouse embryonic stem (ES) cells in vitro. After more than 10 years, where have these researches reached? Which are the major successes achieved and the problems still remaining to be solved? Although during the last years, many reviews have been published about these topics, in the present work, we will focus on an aspect that has been little considered so far, namely a strict comparison between the in vitro and in vivo developmental capabilities of the primordial germ cells (PGCs) isolated from the embryo and the PGC-like cells (PGC-LCs) produced in vitro from different types of stem cells in the mouse, the species in which most investigation has been carried out. Actually, the formation and differentiation of PGCs are crucial for both male and female gametogenesis, and the faithful production of PGCs in vitro represents the basis for obtaining functional germ cells. PMID:26469955

  8. Gonadogenesis and slow proliferation of germ cells in juveniles of cultured yellowfin tuna, Thunnus albacares.

    PubMed

    Kobayashi, Toru; Honryo, Tomoki; Agawa, Yasuo; Sawada, Yoshifumi; Tapia, Ileana; Macìas, Karla A; Cano, Amado; Scholey, Vernon P; Margulies, Daniel; Yagishita, Naoki

    2015-06-01

    To develop techniques for seedling production of yellowfin tuna, the behavior of primordial germ cells (PGCs) and gonadogenesis were examined at 1-30 days post hatching (dph) using morphometric analysis, histological examination, and in situ hybridization. Immediately after hatching, PGCs were located on the dorsal side of the posterior end of the rectum under the peritoneum of the larvae, and at 3 dph they came into contact with stromal cells. PGCs and stromal cells gradually moved forward from the anus prior to 5 dph. At 7-10 dph, germ cells were surrounded by stromal cells and the gonadal primordia were formed. In individuals collected at 12 dph, PGCs were detected by in situ hybridization using a vasa mRNA probe that is a germ-cell-specific detection marker. The proliferation of germ cells in the gonadal primordia began at 7-10 dph. We observed double the number of germ cells at 30 dph (22 ± 3.2 cells), compared to that at 1 dph (11 ± 2.1 cells). Therefore, based on our data and previous reports, the initial germ cell proliferation of yellowfin tuna is relatively slower than that of other fish species. PMID:26051459

  9. Derivation of Primordial germ cells from Human Embryonic and Induced Pluripotent Stem Cells is significantly improved by co-culture with human fetal gonadal cells

    PubMed Central

    Park, Tae Sub; Galic, Zoran; Conway, Anne E.; Lindgren, Anne; Van Handel, Benjamin J.; Magnusson, Mattias; Richter, Laura; Teitell, Michael A.; Mikkola, Hanna K.A; Lowry, William E.; Plath, Kathrin; Clark, Amander T

    2012-01-01

    The derivation of germ cells from human embryonic stem cells (hESCs) or human induced pluripotent stem (hIPS) cells represents a desirable experimental model and potential strategy for treating infertility. In the current study we developed a triple biomarker assay for identifying and isolating human primordial germ cells (PGCs) by first evaluating human PGC formation during the first trimester in vivo. Next, we applied this technology to characterizing in vitro derived PGCs (iPGCs) from pluripotent cells. Our results show that co-differentiation of hESCs on human fetal gonadal stromal cells significantly improves the efficiency of generating iPGCs. Furthermore, the efficiency was comparable between various pluripotent cell lines regardless of origin from the inner cell mass of human blastocysts (hESCs), or reprogramming of human skin fibroblasts (hIPS). In order to better characterize the iPGCs we performed Real time PCR, microarray and bisulfite sequencing. Our results show that iPGCs at day 7 of differentiation are transcriptionally distinct from the somatic cells, expressing genes associated with pluripotency and germ cell development while repressing genes associated with somatic differentiation (specifically multiple HOX genes). Using bisulfite sequencing, we show that iPGCs initiate imprint erasure from differentially methylated imprinted regions by day 7 of differentiation. However, iPGCs derived from hIPS cells do not initiate imprint erasure as efficiently. In conclusion, our results indicate that triple positive iPGCs derived from pluripotent cells differentiated on hFGS cells correspond to committed first trimester germ cells (before 9 weeks) that have initiated the process of imprint erasure. PMID:19350678

  10. bFGF signaling-mediated reprogramming of porcine primordial germ cells.

    PubMed

    Zhang, Yu; Ma, Jing; Li, Hai; Lv, Jiawei; Wei, Renyue; Cong, Yimei; Liu, Zhonghua

    2016-05-01

    Primordial germ cells (PGCs) have the ability to be reprogrammed into embryonic germ cells (EGCs) in vitro and are an alternative source of embryonic stem cells. Other than for the mouse, the systematic characterization of mammalian PGCs is still lacking, especially the process by which PGCs convert to pluripotency. This hampers the understanding of germ cell development and the derivation of authenticated EGCs from other species. We observed the morphological development of the genital ridge from Bama miniature pigs and found primary sexual differentiation in the E28 porcine embryo, coinciding with Blimp1 nuclear exclusion in PGCs. To explore molecular events involved in porcine PGC reprogramming, transcriptome data of porcine EGCs and fetal fibroblasts (FFs) were assembled and 1169 differentially expressed genes were used for Gene Ontology analysis. These genes were significantly enriched in cell-surface receptor-linked signal transduction, in agreement with the activation of LIF/Stat3 signaling and FGF signaling during the derivation of porcine EG-like cells. Using a growth-factor-defined culture system, we explored the effects of bFGF on the process and found that bFGF not only functioned at the very beginning of PGC dedifferentiation by impeding Blimp1 nuclear expression via a PI3K/AKT-dependent pathway but also maintained the viability of cultured PGCs thereafter. These results provide further insights into the development of germ cells from livestock and the mechanism of porcine PGC reprogramming. PMID:26613602

  11. Compensatory proliferation of endogenous chicken primordial germ cells after elimination by busulfan treatment

    PubMed Central

    2013-01-01

    Introduction Primordial germ cells (PGCs) are the major population of cells in the developing bilateral embryonic gonads. Little is known about the cellular responses of PGCs after treatment with toxic chemicals such as busulfan during embryo development. In this study, we investigated the elimination, restorative ability, and cell cycle status of endogenous chicken PGCs after busulfan treatment. Methods Busulfan was emulsified in sesame oil by a dispersion-emulsifying system and injected into the chick blastoderm (embryonic stage X). Subsequently, we conducted flow cytometry analysis to evaluate changes in the PGC population and cell cycle status, and immunohistochemistry to examine the germ cell proliferation. Results Results of flow cytometry and immunohistochemistry analyses after busulfan treatment showed that the proportion of male PGCs at embryonic day 9 and female PGCs at embryonic day 7 were increased by approximately 60% when compared with embryonic day 5.5. This result suggests the existence of a compensatory mechanism in PGCs in response to the cytotoxic effects of busulfan. Results of cell cycling analysis showed that the germ cells in the G0/G1 phase were significantly decreased, while S/G2/M-phase germ cells were significantly increased in the treatment group compared with the untreated control group in both 9-day-old male and female embryos. In addition, in the proliferation analysis with 5-ethynyl-2′-deoxyuridine (EdU) incorporation, we found that the proportion of EdU-positive cells among VASA homolog-positive cells in the 9-day embryonic gonads of the busulfan-treated group was significantly higher than in the control group. Conclusions We conclude that PGCs enter a restoration pathway by promoting their cell cycle after experiencing a cytotoxic effect. PMID:24405696

  12. A germ cell determinant reveals parallel pathways for germ line development in Caenorhabditis elegans.

    PubMed

    Mainpal, Rana; Nance, Jeremy; Yanowitz, Judith L

    2015-10-15

    Despite the central importance of germ cells for transmission of genetic material, our understanding of the molecular programs that control primordial germ cell (PGC) specification and differentiation are limited. Here, we present findings that X chromosome NonDisjunction factor-1 (XND-1), known for its role in regulating meiotic crossover formation, is an early determinant of germ cell fates in Caenorhabditis elegans. xnd-1 mutant embryos display a novel 'one PGC' phenotype as a result of G2 cell cycle arrest of the P4 blastomere. Larvae and adults display smaller germ lines and reduced brood size consistent with a role for XND-1 in germ cell proliferation. Maternal XND-1 proteins are found in the P4 lineage and are exclusively localized to the nucleus in PGCs, Z2 and Z3. Zygotic XND-1 turns on shortly thereafter, at the ∼300-cell stage, making XND-1 the earliest zygotically expressed gene in worm PGCs. Strikingly, a subset of xnd-1 mutants lack germ cells, a phenotype shared with nos-2, a member of the conserved Nanos family of germline determinants. We generated a nos-2 null allele and show that nos-2; xnd-1 double mutants display synthetic sterility. Further removal of nos-1 leads to almost complete sterility, with the vast majority of animals without germ cells. Sterility in xnd-1 mutants is correlated with an increase in transcriptional activation-associated histone modification and aberrant expression of somatic transgenes. Together, these data strongly suggest that xnd-1 defines a new branch for PGC development that functions redundantly with nos-2 and nos-1 to promote germline fates by maintaining transcriptional quiescence and regulating germ cell proliferation. PMID:26395476

  13. Pluripotent stem cells derived from mouse primordial germ cells by small molecule compounds.

    PubMed

    Kimura, Tohru; Kaga, Yoshiaki; Sekita, Yoichi; Fujikawa, Keita; Nakatani, Tsunetoshi; Odamoto, Mika; Funaki, Soichiro; Ikawa, Masahito; Abe, Kuniya; Nakano, Toru

    2015-01-01

    Primordial germ cells (PGCs) can give rise to pluripotent stem cells known as embryonic germ cells (EGCs) when cultured with basic fibroblast growth factor (bFGF), stem cell factor (SCF), and leukemia inhibitory factor. Somatic cells can give rise to induced pluripotent stem cells (iPSCs) by introduction of the reprogramming transcription factors Oct4, Sox2, and Klf4. The effects of Sox2 and Klf4 on somatic cell reprogramming can be reproduced using the small molecule compounds, transforming growth factor-β receptor (TGFβR) inhibitor and Kempaullone, respectively. Here we examined the effects of TGFβR inhibitor and Kempaullone on EGC derivation from PGCs. Treatment of PGCs with TGFβR inhibitor and/or Kempaullone generated pluripotent stem cells under standard embryonic stem cell (ESC) culture conditions without bFGF and SCF, which we termed induced EGCs (iEGCs). The derivation efficiency of iEGCs was dependent on the differentiation stage and sex. DNA methylation levels of imprinted genes in iEGCs were reduced, with the exception of the H19 gene. The promoters of genes involved in germline development were generally hypomethylated in PGCs, but three germline genes showed comparable DNA methylation levels among iEGs, ESCs, and iPSCs. These results show that PGCs can be reprogrammed into pluripotent state using small molecule compounds, and that DNA methylation of these germline genes is not maintained in iEGCs. PMID:25186651

  14. The ability of mouse nuclear transfer embryonic stem cells to differentiate into primordial germ cells

    PubMed Central

    Mansouri, Vahid; Salehi, Mohammad; Nourozian, Mohsen; Fadaei, Fatemeh; Farahani, Reza Mastery; Piryaei, Abbas; Delbari, Ali

    2015-01-01

    Nuclear transfer embryonic stem cells (ntESCs) show stem cell characteristics such as pluripotency but cause no immunological disorders. Although ntESCs are able to differentiate into somatic cells, the ability of ntESCs to differentiate into primordial germ cells (PGCs) has not been examined. In this work, we examined the capacity of mouse ntESCs to differentiate into PGCs in vitro. ntESCs aggregated to form embryoid bodies (EB) in EB culture medium supplemented with bone morphogenetic protein 4(BMP4) as the differentiation factor. The expression level of specific PGC genes was compared at days 4 and 8 using real time PCR. Flow cytometry and immunocytochemical staining were used to detect Mvh as a specific PGC marker. ntESCs expressed particular genes related to different stages of PGC development. Flow cytometry and immunocytochemical staining confirmed the presence of Mvh protein in a small number of cells. There were significant differences between cells that differentiated into PGCs in the group treated with Bmp4 compared to non-treated cells. These findings indicate that ntESCs can differentiate into putative PGCs. Improvement of ntESC differentiation into PGCs may be a reliable means of producing mature germ cells. PMID:26273226

  15. Stochastic specification of primordial germ cells from mesoderm precursors in axolotl embryos.

    PubMed

    Chatfield, Jodie; O'Reilly, Marie-Anne; Bachvarova, Rosemary F; Ferjentsik, Zoltan; Redwood, Catherine; Walmsley, Maggie; Patient, Roger; Loose, Mathew; Johnson, Andrew D

    2014-06-01

    A common feature of development in most vertebrate models is the early segregation of the germ line from the soma. For example, in Xenopus and zebrafish embryos primordial germ cells (PGCs) are specified by germ plasm that is inherited from the egg; in mice, Blimp1 expression in the epiblast mediates the commitment of cells to the germ line. How these disparate mechanisms of PGC specification evolved is unknown. Here, in order to identify the ancestral mechanism of PGC specification in vertebrates, we studied PGC specification in embryos from the axolotl (Mexican salamander), a model for the tetrapod ancestor. In the axolotl, PGCs develop within mesoderm, and classic studies have reported their induction from primitive ectoderm (animal cap). We used an axolotl animal cap system to demonstrate that signalling through FGF and BMP4 induces PGCs. The role of FGF was then confirmed in vivo. We also showed PGC induction by Brachyury, in the presence of BMP4. These conditions induced pluripotent mesodermal precursors that give rise to a variety of somatic cell types, in addition to PGCs. Irreversible restriction of the germ line did not occur until the mid-tailbud stage, days after the somatic germ layers are established. Before this, germline potential was maintained by MAP kinase signalling. We propose that this stochastic mechanism of PGC specification, from mesodermal precursors, is conserved in vertebrates. PMID:24917499

  16. Chicken stem cell factor enhances primordial germ cell proliferation cooperatively with fibroblast growth factor 2

    PubMed Central

    MIYAHARA, Daichi; OISHI, Isao; MAKINO, Ryuichi; KURUMISAWA, Nozomi; NAKAYA, Ryuma; ONO, Tamao; KAGAMI, Hiroshi; TAGAMI, Takahiro

    2015-01-01

    An in vitro culture system of chicken primordial germ cells (PGCs) has been recently developed, but the growth factor involved in the proliferation of PGCs is largely unknown. In the present study, we investigated the growth effects of chicken stem cell factor (chSCF) on the in vitro proliferation of chicken PGCs. We established two feeder cell lines (buffalo rat liver cells; BRL cells) that stably express the putative secreted form of chSCF (chSCF1-BRL) and membrane bound form of chSCF (chSCF2-BRL). Cultured PGC lines were incubated on chSCF1 or chSCF2-BRL feeder cells with fibroblast growth factor 2 (FGF2), and growth effects of each chSCF isoform were investigated. The in vitro proliferation rate of the PGCs cultured on chSCF2-BRL at 20 days of culture was more than threefold higher than those cultured on chSCF1-BRL cells and more than fivefold higher than those cultured on normal BRL cells. Thus, use of chSCF2-BRL feeder layer was effective for in vitro proliferation of chicken PGCs. However, the acceleration of PGC proliferation on chSCF2-BRL was not observed without FGF2, suggesting that chSCF2 would act as a proliferation co-factor of FGF2. We transferred the PGCs cultured on chSCF2-BRL cells to recipient embryos, generated germline chimeric chickens and assessed the germline competency of cultured PGCs by progeny test. Donor-derived progenies were obtained, and the frequency of germline transmission was 3.39%. The results of this study demonstrate that chSCF2 induces hyperproliferation of chicken PGCs retaining germline competency in vitro in cooperation with FGF2. PMID:26727404

  17. Novel technique for visualizing primordial germ cells in sturgeons (Acipenser ruthenus, A. gueldenstaedtii, A. baerii, and Huso huso).

    PubMed

    Saito, Taiju; Psenicka, Martin

    2015-10-01

    Primordial germ cells (PGCs) are the origin of all germ cells in developing embryos. In the sturgeon embryo, PGCs develop from the vegetal hemisphere, which mainly acts as an extraembryonic source of nutrition. Current methods for studying sturgeon PGCs require either killing the fish or using costly and time-consuming histological procedures. Here, we demonstrate that visualization of sterlet (Acipenser ruthenus>) PGCs in vivo is feasible by simply labeling the vegetal hemisphere with fluorescein isothiocyanate (FITC)-dextran. We injected FITC-dextrans, with molecular weights varying between 10 000 and 2 000 000, into the vegetal pole of 1- to 4-cell stage embryos. At the neurula to tail-bud developmental stages, FITC-positive PGC-like cells appeared ventrally around the developing tail bud in the experimental group that received a high-molecular-weight FITC-dextran. The highest average number of FITC-positive PGC-like cells was observed in embryos injected with FITC-dextran having a molecular weight of 500 000 (FD-500). The pattern of migration of the labeled cells was identical to that of PGCs, clearly indicating that the FITC-positive PGC-like cells were PGCs. Labeled vegetal cells, except for the PGCs, were digested and excreted before the embryos starting feeding. FITC-labeled PGCs were observed in the developing gonads of fish for at least 3 mo after injection. We also found that FD-500 could be used to visualize PGCs in other sturgeon species. To the best of our knowledge, this report is the first to demonstrate in any animal species that PGCs can be visualized in vivo for a long period by the injection of a simple reagent. PMID:26134864

  18. Migratory and adhesive properties of Xenopus laevis primordial germ cells in vitro

    PubMed Central

    Dzementsei, Aliaksandr; Schneider, David; Janshoff, Andreas; Pieler, Tomas

    2013-01-01

    Summary The directional migration of primordial germ cells (PGCs) to the site of gonad formation is an advantageous model system to study cell motility. The embryonic development of PGCs has been investigated in different animal species, including mice, zebrafish, Xenopus and Drosophila. In this study we focus on the physical properties of Xenopus laevis PGCs during their transition from the passive to the active migratory state. Pre-migratory PGCs from Xenopus laevis embryos at developmental stages 17–19 to be compared with migratory PGCs from stages 28–30 were isolated and characterized in respect to motility and adhesive properties. Using single-cell force spectroscopy, we observed a decline in adhesiveness of PGCs upon reaching the migratory state, as defined by decreased attachment to extracellular matrix components like fibronectin, and a reduced adhesion to somatic endodermal cells. Data obtained from qPCR analysis with isolated PGCs reveal that down-regulation of E-cadherin might contribute to this weakening of cell-cell adhesion. Interestingly, however, using an in vitro migration assay, we found that movement of X. laevis PGCs can also occur independently of specific interactions with their neighboring cells. The reduction of cellular adhesion during PGC development is accompanied by enhanced cellular motility, as reflected in increased formation of bleb-like protrusions and inferred from electric cell-substrate impedance sensing (ECIS) as well as time-lapse image analysis. Temporal alterations in cell shape, including contraction and expansion of the cellular body, reveal a higher degree of cellular dynamics for the migratory PGCs in vitro. PMID:24285703

  19. Single cell analysis facilitates staging of Blimp1-dependent primordial germ cells derived from mouse embryonic stem cells.

    PubMed

    Vincent, John J; Li, Ziwei; Lee, Serena A; Liu, Xian; Etter, Marisabel O; Diaz-Perez, Silvia V; Taylor, Sara K; Gkountela, Sofia; Lindgren, Anne G; Clark, Amander T

    2011-01-01

    The cell intrinsic programming that regulates mammalian primordial germ cell (PGC) development in the pre-gonadal stage is challenging to investigate. To overcome this we created a transgene-free method for generating PGCs in vitro (iPGCs) from mouse embryonic stem cells (ESCs). Using labeling for SSEA1 and cKit, two cell surface molecules used previously to isolate presumptive iPGCs, we show that not all SSEA1+/cKit+ double positive cells exhibit a PGC identity. Instead, we determined that selecting for cKit(bright) cells within the SSEA1+ fraction significantly enriches for the putative iPGC population. Single cell analysis comparing SSEA1+/cKit(bright) iPGCs to ESCs and embryonic PGCs demonstrates that 97% of single iPGCs co-express PGC signature genes Blimp1, Stella, Dnd1, Prdm14 and Dazl at similar levels to e9.5-10.5 PGCs, whereas 90% of single mouse ESC do not co-express PGC signature genes. For the 10% of ESCs that co-express PGC signature genes, the levels are significantly lower than iPGCs. Microarray analysis shows that iPGCs are transcriptionally distinct from ESCs and repress gene ontology groups associated with mesoderm and heart development. At the level of chromatin, iPGCs contain 5-methyl cytosine bases in their DNA at imprinted and non-imprinted loci, and are enriched in histone H3 lysine 27 trimethylation, yet do not have detectable levels of Mvh protein, consistent with a Blimp1-positive pre-gonadal PGC identity. In order to determine whether iPGC formation is dependent upon Blimp1, we generated Blimp1 null ESCs and found that loss of Blimp1 significantly depletes SSEA1/cKit(bright) iPGCs. Taken together, the generation of Blimp1-positive iPGCs from ESCs constitutes a robust model for examining cell-intrinsic regulation of PGCs during the Blimp1-positive stage of development. PMID:22194959

  20. Tracing of Xenopus tropicalis germ plasm and presumptive primordial germ cells with the Xenopus tropicalis DAZ-like gene.

    PubMed

    Sekizaki, Hiroyuki; Takahashi, Shuji; Tanegashima, Kousuke; Onuma, Yasuko; Haramoto, Yoshikazu; Asashima, Makoto

    2004-02-01

    A gamete is derived initially from a presumptive primordial germ cell (pPGC) and transmits genetic potential to the next generation. Xenopus tropicalis, which is a close relative of Xenopus laevis, has a diploid genome and advantages for genetic and genomic research; however, little is known about the developmental mechanism of its germinal lineage. Here, we identified the Xenopus tropicalis DAZ-like gene (Xtdazl), which encodes RNA-binding proteins homologous to Xdazl in Xenopus laevis and examined the expression patterns of Xtdazl transcripts during embryogenesis. In this work, we showed that Xtdazl mRNA was localized in the germ plasm and was expressed from the previtellogenic oocyte to early tadpole, in testis and ovary. The same localization patterns have been reported in Xenopus laevis germ plasm and pPGCs. These results indicate that Xtdazl mRNA is the first specific marker of germ plasm and pPGCs in Xenopus tropicalis and is very useful to trace Xenopus tropicalis pPGCs, including germ plasm until the early tadpole stage. PMID:14745962

  1. Testicular germ cell tumors.

    PubMed

    Looijenga, Leendert H J

    2014-02-01

    Human germ cell tumors are of interest because of their epidemiology, clinical behavior and pathobiology. Histologically, they are subdivided into various elements, with similarities to embryogenesis. Recent insights resulted in a division of five types of human germ cell tumors. In the context of male germ cells, three are relevant; Type I: teratomas and yolk sac tumors of neonates and infants; Type II: seminomas and nonseminomas of (predominantly) adolescents and adults; and Type III: spermatocytic seminomas of the elderly. Recent studies led to significant increases in understanding of the parameters involved in the earliest pathogenetic steps of human germ cells tumors, in particularly the seminomas and nonseminomas (Type II). In case of a disturbed gonadal physiology, either due to the germ cell itself, or the micro-environment, embryonic germ cells during a specific window of sensitization can be blocked in their maturation, resulting in carcinoma in situ or gonadoblastoma, the precursors of seminomas and nonseminomas. The level of testicularization of the gonad determines the histological composition of the precursor. These insights will allow better definition of individuals at risk to develop a germ cell malignancy, with putative preventive measurements, and allow better selection of scientific approaches to elucidate the pathogenesis. PMID:24683949

  2. Primordial germ cells: the first cell lineage or the last cells standing?

    PubMed

    Johnson, Andrew D; Alberio, Ramiro

    2015-08-15

    Embryos of many animal models express germ line determinants that suppress transcription and mediate early germ line commitment, which occurs before the somatic cell lineages are established. However, not all animals segregate their germ line in this manner. The 'last cell standing' model describes primordial germ cell (PGC) development in axolotls, in which PGCs are maintained by an extracellular signalling niche, and germ line commitment occurs after gastrulation. Here, we propose that this 'stochastic' mode of PGC specification is conserved in vertebrates, including non-rodent mammals. We postulate that early germ line segregation liberates genetic regulatory networks for somatic development to evolve, and that it therefore emerged repeatedly in the animal kingdom in response to natural selection. PMID:26286941

  3. Primordial germ cells: the first cell lineage or the last cells standing?

    PubMed Central

    Johnson, Andrew D.; Alberio, Ramiro

    2015-01-01

    Embryos of many animal models express germ line determinants that suppress transcription and mediate early germ line commitment, which occurs before the somatic cell lineages are established. However, not all animals segregate their germ line in this manner. The ‘last cell standing’ model describes primordial germ cell (PGC) development in axolotls, in which PGCs are maintained by an extracellular signalling niche, and germ line commitment occurs after gastrulation. Here, we propose that this ‘stochastic’ mode of PGC specification is conserved in vertebrates, including non-rodent mammals. We postulate that early germ line segregation liberates genetic regulatory networks for somatic development to evolve, and that it therefore emerged repeatedly in the animal kingdom in response to natural selection. PMID:26286941

  4. Guidance of primordial germ cell migration by the chemokine SDF-1.

    PubMed

    Doitsidou, Maria; Reichman-Fried, Michal; Stebler, Jürg; Köprunner, Marion; Dörries, Julia; Meyer, Dirk; Esguerra, Camila V; Leung, TinChung; Raz, Erez

    2002-11-27

    The signals directing primordial germ cell (PGC) migration in vertebrates are largely unknown. We demonstrate that sdf-1 mRNA is expressed in locations where PGCs are found and toward which they migrate in wild-type as well as in mutant embryos in which PGC migration is abnormal. Knocking down SDF-1 or its receptor CXCR4 results in severe defects in PGC migration. Specifically, PGCs that do not receive the SDF-1 signal exhibit lack of directional movement toward their target and arrive at ectopic positions within the embryo. Finally, we show that the PGCs can be attracted toward an ectopic source of the chemokine, strongly suggesting that this molecule provides a key directional cue for the PGCs. PMID:12464177

  5. Oct4 is required for primordial germ cell survival

    PubMed Central

    Kehler, James; Tolkunova, Elena; Koschorz, Birgit; Pesce, Maurizio; Gentile, Luca; Boiani, Michele; Lomelí, Hilda; Nagy, Andras; McLaughlin, K John; Schöler, Hans R; Tomilin, Alexey

    2004-01-01

    Previous studies have shown that Oct4 has an essential role in maintaining pluripotency of cells of the inner cell mass (ICM) and embryonic stem cells. However, Oct4 null homozygous embryos die around the time of implantation, thus precluding further analysis of gene function during development. We have used the conditional Cre/loxP gene targeting strategy to assess Oct4 function in primordial germ cells (PGCs). Loss of Oct4 function leads to apoptosis of PGCs rather than to differentiation into a trophectodermal lineage, as has been described for Oct4-deficient ICM cells. These new results suggest a previously unknown function of Oct4 in maintaining viability of mammalian germline. PMID:15486564

  6. The mouse homolog of Drosophila Vasa is required for the development of male germ cells

    PubMed Central

    Tanaka, Satomi S.; Toyooka, Yayoi; Akasu, Ryuko; Katoh-Fukui, Yuko; Nakahara, Yoko; Suzuki, Rika; Yokoyama, Minesuke; Noce, Toshiaki

    2000-01-01

    Restricted expression of a mouse Vasa homolog gene (Mvh) expression is first detected in primordial germ cells (PGCs) after colonization of the genital ridges. Subsequently, Mvh is maintained until postmeiotic germ cells are formed. Here, we demonstrate that male mice homozygous for a targeted mutation of Mvh exhibit a reproductive deficiency. Male homozygotes produce no sperm in the testes, where premeiotic germ cells cease differentiation by the zygotene stage and undergo apoptotic death. In addition, the proliferation of PGCs that colonize homozygous male gonads is significantly hampered, and OCT-3/4 expression appears to be reduced. These results indicate that the loss of Mvh function causes a deficiency in the proliferation and differentiation of mouse male germ cells. PMID:10766740

  7. Bone morphogenetic protein 4 mediates human embryonic germ cell derivation.

    PubMed

    Hiller, Marc; Liu, Cyndi; Blumenthal, Paul D; Gearhart, John D; Kerr, Candace L

    2011-02-01

    Human primordial germ cells (PGCs) have proven to be a source of pluripotent stem cells called embryonic germ cells (EGCs). Unlike embryonic stem cells, virtually little is known regarding the factors that regulate EGC survival and maintenance. In mice, the growth factor bone morphogenetic protein 4 (BMP4) has been shown to be required for maintaining mouse embryonic stem cells, and disruptions in this gene lead to defects in mouse PGC specification. Here, we sought to determine whether recombinant human BMP4 could influence EGC derivation and/or human PGC survival. We found that the addition of recombinant BMP4 increased the number of human PGCs after 1 week of culture in a dose-responsive manner. The efficiency of EGC derivation and maintenance in culture was also enhanced by the presence of recombinant BMP4 based on alkaline phosphatase and OCT4 staining. In addition, an antagonist of the BMP4 pathway, Noggin, decreased PGC proliferation and led to an increase in cystic embryoid body formation. Quantitative real-time (qRT)-polymerase chain reaction analyses and immunostaining confirmed that the constituents of the BMP4 pathway were upregulated in EGCs versus PGCs. Downstream activators of the BMP4 pathway such as ID1 and phosphorylated SMADs 1 and 5 were also expressed, suggesting a role of this growth factor in EGC pluripotency. PMID:20486775

  8. Dynamics of 5-methylcytosine and 5-hydroxymethylcytosine during germ cell reprogramming.

    PubMed

    Yamaguchi, Shinpei; Hong, Kwonho; Liu, Rui; Inoue, Azusa; Shen, Li; Zhang, Kun; Zhang, Yi

    2013-03-01

    Previous studies have revealed that mouse primordial germ cells (PGCs) undergo genome-wide DNA methylation reprogramming to reset the epigenome for totipotency. However, the precise 5-methylcytosine (5mC) dynamics and its relationship with the generation of 5-hydroxymethylcytosine (5hmC) are not clear. Here we analyzed the dynamics of 5mC and 5hmC during PGC reprograming and germ cell development. Unexpectedly, we found a specific period (E8.5-9.5) during which both 5mC and 5hmC levels are low. Subsequently, 5hmC levels increase reaching its peak at E11.5 and gradually decrease until E13.5 likely by replication-dependent dilution. Interestingly, 5hmC is enriched in chromocenters during this period. While this germ cell-specific 5hmC subnuclear localization pattern is maintained in female germ cells even in mature oocytes, such pattern is gradually lost in male germ cells as mitotic proliferation resumes during the neonatal stage. Pericentric 5hmC plays an important role in silencing major satellite repeat, especially in female PGCs. Global transcriptome analysis by RNA-seq revealed that the great majority of differentially expressed genes from E9.5 to 13.5 are upregulated in both male and female PGCs. Although only female PGCs enter meiosis during the prenatal stage, meiosis-related and a subset of imprinted genes are significantly upregulated in both male and female PGCs at E13.5. Thus, our study not only reveals the dynamics of 5mC and 5hmC during PGC reprogramming and germ cell development, but also their potential role in epigenetic reprogramming and transcriptional regulation of meiotic and imprinted genes. PMID:23399596

  9. Exposure to Endocrine Disruptor Induces Transgenerational Epigenetic Deregulation of MicroRNAs in Primordial Germ Cells

    PubMed Central

    Brieño-Enríquez, Miguel A.; García-López, Jesús; Cárdenas, David B.; Guibert, Sylvain; Cleroux, Elouan; Děd, Lukas; Hourcade, Juan de Dios; Pěknicová, Jana; Weber, Michael; del Mazo, Jesús

    2015-01-01

    In mammals, germ cell differentiation is initiated in the Primordial Germ Cells (PGCs) during fetal development. Prenatal exposure to environmental toxicants such as endocrine disruptors may alter PGC differentiation, development of the male germline and induce transgenerational epigenetic disorders. The anti-androgenic compound vinclozolin represents a paradigmatic example of molecule causing transgenerational effects on germ cells. We performed prenatal exposure to vinclozolin in mice and analyzed the phenotypic and molecular changes in three successive generations. A reduction in the number of embryonic PGCs and increased rate of apoptotic cells along with decrease of fertility rate in adult males were observed in F1 to F3 generations. Blimp1 is a crucial regulator of PGC differentiation. We show that prenatal exposure to vinclozolin deregulates specific microRNAs in PGCs, such as miR-23b and miR-21, inducing disequilibrium in the Lin28/let-7/Blimp1 pathway in three successive generations of males. As determined by global maps of cytosine methylation, we found no evidence for prominent changes in DNA methylation in PGCs or mature sperm. Our data suggest that embryonic exposure to environmental endocrine disruptors induces transgenerational epigenetic deregulation of expression of microRNAs affecting key regulatory pathways of germ cells differentiation. PMID:25897752

  10. Germline development in amniotes: A paradigm shift in primordial germ cell specification.

    PubMed

    Bertocchini, Federica; Chuva de Sousa Lopes, Susana M

    2016-08-01

    In the field of germline development in amniote vertebrates, primordial germ cell (PGC) specification in birds and reptiles remains controversial. Avians are believed to adopt a predetermination or maternal specification mode of PGC formation, contrary to an inductive mode employed by mammals and, supposedly, reptiles. Here, we revisit and review some key aspects of PGC development that channelled the current subdivision, and challenge the position of birds and reptiles as well as the 'binary' evolutionary model of PGC development in vertebrates. We propose an alternative view on PGC specification where germ plasm plays a role in laying the foundation for the formation of PGC precursors (pPGC), but not necessarily of PGCs. Moreover, inductive mechanisms may be necessary for the transition from pPGCs to PGCs. Within this framework, the implementation of data from birds and reptiles could provide new insights on the evolution of PGC specification in amniotes. PMID:27273724

  11. 17β-Estradiol induces supernumerary primordial germ cells in embryos of the polychaete Platynereis dumerilii.

    PubMed

    Lidke, Anika K; Bannister, Stephanie; Löwer, Andreas M; Apel, David M; Podleschny, Martina; Kollmann, Martin; Ackermann, Christian F; García-Alonso, Javier; Raible, Florian; Rebscher, Nicole

    2014-01-15

    In the polychaete Platynereis dumerilii exactly four primordial germ cells (PGCs) arise in early development and are subject to a transient mitotic arrest until the animals enter gametogenesis. In order to unravel the mechanisms controlling the number of PGCs in Platynereis, we tested whether the steroid 17β-estradiol (E2) is able to induce PGC proliferation, as it had been described in other species. Our data provide strong support for such a mechanism, showing that E2 significantly increases the occurrence of larvae with supernumerary PGCs in Platynereis in a dose dependent manner. E2 responsiveness is restricted to early developmental stages, when the PGCs are specified. During these stages, embryos exhibit high expression levels of the estradiol receptor (ER). The ER transcript localizes to the yolk-free cytoplasm of unfertilized eggs and segregates into the micromeres during cleavage stages. Nuclear ER protein is found asymmetrically distributed between daughter cells. Neither transcript nor protein is detectable in PGCs at larval stages. Addition of the specific estradiol receptor inhibitor ICI-182,780 (ICI) abolishes the proliferative effect of E2, suggesting that it is mediated by ER signaling. Our study reports for the first time an ER mediated proliferative effect of E2 on PGCs in an invertebrate organism. PMID:24287341

  12. Hidden in the crowd: primordial germ cells and somatic stem cells in the mesodermal posterior growth zone of the polychaete Platynereis dumerillii are two distinct cell populations

    PubMed Central

    2012-01-01

    Background In the polychaete Platynereis, the primordial germ cells (PGCs) emerge from the vasa, piwi, and PL10 expressing mesodermal posterior growth zone (MPGZ) at the end of larval development, suggesting a post-embryonic formation from stem cells. Methods In order to verify this hypothesis, embryos and larvae were pulse labeled with the proliferation marker 5-ethynyl-2'-deoxyuridine (EdU) at different stages of development. Subsequently, the PGCs were visualized in 7-day-old young worms using antibodies against the Vasa protein. Results Surprisingly, the primordial germ cells of Platynereis incorporate EdU only shortly before gastrulation (6-8 hours post fertilization (hpf)), which coincides with the emergence of four small blastomeres from the mesoblast lineage. We conclude that these so-called 'secondary mesoblast cells' constitute the definitive PGCs in Platynereis. In contrast, the cells of the MPGZ incorporate EdU only from the pre-trochophore stage onward (14 hpf). Conclusion While PGCs and the cells of the MPGZ in Platynereis are indistinguishable in morphology and both express the germline markers vasa, nanos, and piwi, a distinct cluster of PGCs is detectable anterior of the MPGZ following EdU pulse-labeling. Indeed the PGCs form independently from the stem cells of the MPGZ prior to gastrulation. Our data suggest an early PGC formation in the polychaete by preformation rather than by epigenesis. PMID:22512981

  13. The migrations of Drosophila muscle founders and primordial germ cells are interdependent.

    PubMed

    Stepanik, Vincent; Dunipace, Leslie; Bae, Young-Kyung; Macabenta, Frank; Sun, Jingjing; Trisnadi, Nathanie; Stathopoulos, Angelike

    2016-09-01

    Caudal visceral mesoderm (CVM) cells migrate from posterior to anterior of the Drosophila embryo as two bilateral streams of cells to support the specification of longitudinal muscles along the midgut. To accomplish this long-distance migration, CVM cells receive input from their environment, but little is known about how this collective cell migration is regulated. In a screen we found that wunen mutants exhibit CVM cell migration defects. Wunens are lipid phosphate phosphatases known to regulate the directional migration of primordial germ cells (PGCs). PGC and CVM cell types interact while PGCs are en route to the somatic gonadal mesoderm, and previous studies have shown that CVM impacts PGC migration. In turn, we found here that CVM cells exhibit an affinity for PGCs, localizing to the position of PGCs whether mislocalized or trapped in the endoderm. In the absence of PGCs, CVM cells exhibit subtle changes, including more cohesive movement of the migrating collective, and an increased number of longitudinal muscles is found at anterior sections of the larval midgut. These data demonstrate that PGC and CVM cell migrations are interdependent and suggest that distinct migrating cell types can coordinately influence each other to promote effective cell migration during development. PMID:27578182

  14. Obtaining chicken primordial germ cells used for gene transfer: in vitro and in vivo results.

    PubMed

    Chojnacka-Puchta, Luiza; Sawicka, Dorota; Lakota, Paweł; Plucienniczak, Grazyna; Bednarczyk, Marek; Plucienniczak, Andrzej

    2015-11-01

    Recently, several attempts have been made to create a generation of transgenic chickens via chimeric intermediates produced by primordial germ cells (PGCs) transfer. This study aimed to compare the influences of different chicken PGCs isolated from circulating blood (bPGCs) or gonads (gPGCs), purification (ACK, Percoll or trypsin) and transfection methods (electroporation or lipofection) on the expression of transgenes in vitro and the migration of modified donor cells to the recipient gonads. The highest average frequency of pEGFP-N1 plasmid-transfected bPGCs (75.8%) was achieved with Percoll density gradient centrifugation and electroporation. After ammonium chloride-potassium (ACK) treatment and lipofection, in vitro transgene expression was only detected in 35.2% of bPGCs. Chimeric chickens were produced from these purified, transfected and cultured cells, and the transgene was detected in the gonads of 44 and 42% of the recipient embryos that had been injected with bPGCs and gPGCs, respectively. These data confirmed that the combination of PGC purification via Percoll centrifugation and electroporation was an effective method for producing transgenic chickens. Subsequently, we used this method with expression vectors for gene hIFNα 2a/hepatitis B virus surface antigen (HBsAg) under the control of the ovalbumin promoter to generate G0 transgenic chickens. Consequently, we observed that 4.9% of the hens and 3.5% of the roosters carried the hIFNα 2a gene, whereas 16.7% of the hens and 2.4% of the roosters carried the HBsAg gene, thus undisputedly confirming the exceptional effectiveness of the applied methods. PMID:25737138

  15. Extragonadal Germ Cell Cancer (EGC)

    MedlinePlus

    ... Testicular Cancer Resource Center Extragonadal Germ Cell Cancer (EGC) 95% of all testicular tumors are germ cell ... seen in young adults. Patients with mediastinal nonseminomatous EGC are typically classed as poor risk patients because ...

  16. RNA Granules in Germ Cells

    PubMed Central

    Voronina, Ekaterina; Seydoux, Geraldine; Sassone-Corsi, Paolo; Nagamori, Ippei

    2011-01-01

    Germ granules” are cytoplasmic, nonmembrane-bound organelles unique to germline. Germ granules share components with the P bodies and stress granules of somatic cells, but also contain proteins and RNAs uniquely required for germ cell development. In this review, we focus on recent advances in our understanding of germ granule assembly, dynamics, and function. One hypothesis is that germ granules operate as hubs for the posttranscriptional control of gene expression, a function at the core of the germ cell differentiation program. PMID:21768607

  17. Testicular germ cell tumours.

    PubMed

    Rajpert-De Meyts, Ewa; McGlynn, Katherine A; Okamoto, Keisei; Jewett, Michael A S; Bokemeyer, Carsten

    2016-04-23

    Testicular germ cell tumours are at the crossroads of developmental and neoplastic processes. Their cause has not been fully elucidated but differences in incidences suggest that a combination of genetic and environment factors are involved, with environmental factors predominating early in life. Substantial progress has been made in understanding genetic susceptibility in the past 5 years on the basis of the results of large genome-wide association studies. Testicular germ cell tumours are highly sensitive to radiotherapy and chemotherapy and hence have among the best outcomes of all tumours. Because the tumours occur mainly in young men, preservation of reproductive function, quality of life after treatment, and late effects are crucial concerns. In this Seminar, we provide an overview of advances in the understanding of the epidemiology, genetics, and biology of testicular germ cell tumours. We also summarise the consensus on how to treat testicular germ cell tumours and focus on a few controversies and improvements in the understanding of late effects of treatment and quality of life for survivors. PMID:26651223

  18. Primordial germ cell biology at the beginning of the XXI century.

    PubMed

    De Felici, Massimo

    2009-01-01

    At the XIV Workshop on the Development and Function of the Reproductive Organs held at the Congress Centre of the University of Rome Tor Vergata, Monteporzio Catone, Rome, Italy, the introduction to the first session entitled Mammalian primordial germ cells dedicated to the memory of Anne McLaren, was the occasion for a concise review of the state of art of research on the biology of primordial germ cells (PGCs). This great, unforgettable scientist, who died in a car accident in July 2007, dedicated most of her studies to this field over the last 25 years. Topics briefly reviewed in this Meeting Report are: 1) how the germ line is determined; 2) what are the mechanisms underlying PGC migration; 3) to what extent PGC survival, proliferation and differentiation are cell autonomous or environmentally controlled processes and 4) how the potential for totipotency is retained in PGCs. PMID:19598110

  19. Primordial germ cells in an oligochaete annelid are specified according to the birth rank order in the mesodermal teloblast lineage.

    PubMed

    Kato, Yukie; Nakamoto, Ayaki; Shiomi, Inori; Nakao, Hajime; Shimizu, Takashi

    2013-07-15

    The primordial germ cells (PGCs) in the oligochaete annelid Tubifex tubifex are descentants of the mesodermal (M) teloblast and are located in the two midbody segments X and XI in which they serve as germline precursors forming the testicular gonad and the ovarian gonad, respectively. During embryogenesis, vasa-expressing cells (termed presumptive PGCs or pre-PGCs) emerge in a variable set of midbody segments including the genital segments (X and XI); at the end of embryogenesis, pre-PGCs are confined to the genital segments, where they become PGCs in the juvenile. Here, using live imaging of pre-PGCs, we have demonstrated that during Tubifex embryogenesis, pre-PGCs (defined by Vasa expression) stay in segments where they have emerged, suggesting that it is unlikely that pre-PGCs move intersegmentally during embryogenesis. Thus, it is apparent that pre-PGCs derived from the 10th and 11th M teloblast-derived primary m blast cells (designated m10 and m11) that give rise, respectively, to segments X and XI are specified in situ as PGCs and that those born in other segments become undetectable at the end of embryogenesis. To address the mechanisms for this segment-specific development of PGCs, we have performed a set of cell-transplantation experiments as well as cell-ablation experiments. When m10 and m11 that are normally located in the mid region of the embryo were placed in positions near the anterior end of the host embryo, these cells formed two consecutive segments, which exhibited Vasa-positive PGC-like cells at early juvenile stage. This suggests that in terms of PGC generation, the fates of m10 and m11 remain unchanged even if they are placed in ectopic positions along the anteroposterior axis. Nor was the fate of m10 and m11 changed even if mesodermal blast cell chains preceding or succeeding m10 and m11 were absent. In a previous study, it was shown that PGC development in segments X and XI occurs normally in the absence of the overlying ectoderm. All this

  20. Expression of low density lipoprotein receptor-related protein 4 (Lrp4) gene in the mouse germ cells.

    PubMed

    Yamaguchi, Yasuka L; Tanaka, Satomi S; Kasa, Miyuki; Yasuda, Kunio; Tam, Patrick P L; Matsui, Yasuhisa

    2006-08-01

    The low density lipoprotein receptor-related protein 4 gene (Lrp4) was identified by subtractive screening of cDNAs of the migratory primordial germ cells (PGCs) of E8.5-9.5 embryo and E3.5 blastocysts. Lrp4 is expressed in PGCs in the hindgut and the dorsal mesentery of E9.5 embryos, and in germ cells in the genital ridges of male and female E10.5-13.5 embryos. Lrp4 is also expressed in spermatogonia of the neonatal and adult testes and in the immature oocytes and follicular cells of the adult ovary. The absence of Lrp4 expression in the blastocyst, embryonic stem cells and embryonic germ cells suggests the Lrp4 is a molecular marker that distinguishes the germ cells from embryo-derived pluripotent stem cells. PMID:16434236

  1. Cryopreservation of primordial germ cells by rapid cooling of whole zebrafish (Danio rerio) embryos.

    PubMed

    Higaki, Shogo; Mochizuki, Kentaro; Akashi, Yuichiro; Yamaha, Etsuro; Katagiri, Seiji; Takahashi, Yoshiyuki

    2010-04-01

    The feasibility of cryopreservation of zebrafish (Danio rerio) primordial germ cells (PGCs) by rapid cooling (i.e., vitrification) of dechorionated whole embryos at the 14- to 20-somite stage was investigated. Initially, we examined the glass-forming properties and embryo toxicities of six cryoprotectants: methanol (MeOH), ethylene glycol (EG), glycerol (GC), dimethyl sulfoxide (DMSO), propylene glycol (PG) and 1,3-butylene glycol (1,3-BG). According to the results of glass-forming and embryo toxicity tests, pretreatment solution (PS) containing 2 or 3 M cryoprotectant and vitrification solution (VS) containing 5 M cryoprotectant and 0.5 M sucrose were prepared using each cryoprotectant. Dechorionated embryos, the PGCs of which were visualized by injection of green fluorescence protein-nos1 3'UTR mRNA, were cooled rapidly by plunging into liquid nitrogen after serial exposure to PS and VS. All embryos cooled with MeOH, PG and 1,3-BG showed ice formation during cooling, and few embryos had live PGCs after warming. Most embryos cooled with GC did not show ice formation; however, few embryos had live PGCs. All embryos cooled with EG and most embryos cooled with DMSO had live PGCs when the embryos did not show ice formation during cooling. Based on the number of live PGCs in fresh embryos, the maximum survival rates of PGCs recovered from embryos cooled with EG and DMSO were estimated to be about 40 and 20%, respectively. The present study indicates that rapid cooling of dechorionated whole embryos, especially using EG-based solutions, could be utilized as a simple and promising tool for cryopreservation of PGCs. PMID:19996550

  2. Genome-Wide Profiling of Pluripotent Cells Reveals a Unique Molecular Signature of Human Embryonic Germ Cells

    PubMed Central

    Pashai, Nikta; Hao, Haiping; All, Angelo; Gupta, Siddharth; Chaerkady, Raghothama; De Los Angeles, Alejandro; Gearhart, John D.; Kerr, Candace L.

    2012-01-01

    Human embryonic germ cells (EGCs) provide a powerful model for identifying molecules involved in the pluripotent state when compared to their progenitors, primordial germ cells (PGCs), and other pluripotent stem cells. Microarray and Principal Component Analysis (PCA) reveals for the first time that human EGCs possess a transcription profile distinct from PGCs and other pluripotent stem cells. Validation with qRT-PCR confirms that human EGCs and PGCs express many pluripotency-associated genes but with quantifiable differences compared to pluripotent embryonic stem cells (ESCs), induced pluripotent stem cells (IPSCs), and embryonal carcinoma cells (ECCs). Analyses also identified a number of target genes that may be potentially associated with their unique pluripotent states. These include IPO7, MED7, RBM26, HSPD1, and KRAS which were upregulated in EGCs along with other pluripotent stem cells when compared to PGCs. Other potential target genes were also found which may contribute toward a primed ESC-like state. These genes were exclusively up-regulated in ESCs, IPSCs and ECCs including PARP1, CCNE1, CDK6, AURKA, MAD2L1, CCNG1, and CCNB1 which are involved in cell cycle regulation, cellular metabolism and DNA repair and replication. Gene classification analysis also confirmed that the distinguishing feature of EGCs compared to ESCs, ECCs, and IPSCs lies primarily in their genetic contribution to cellular metabolism, cell cycle, and cell adhesion. In contrast, several genes were found upregulated in PGCs which may help distinguish their unipotent state including HBA1, DMRT1, SPANXA1, and EHD2. Together, these findings provide the first glimpse into a unique genomic signature of human germ cells and pluripotent stem cells and provide genes potentially involved in defining different states of germ-line pluripotency. PMID:22737227

  3. How to make a human germ cell.

    PubMed

    Cooke, Paul S; Nanjappa, Manjunatha K

    2015-01-01

    How the primordial germ cell (PGC) lineage, which eventually gives rise to spermatozoa in males and oocytes in females, is established in the developing mammalian embryo has been a critical topic in both developmental and reproductive biology for many years. There have been significant breakthroughs over the past two decades in establishing both the source of PGCs and the factors that regulate the specification of this lineage in mice, [1] but our understanding of the factors that control PGC development in the human is rudimentary. The SRY-related HMG-box (SOX) family of transcription factors consists of 20 genes in humans and mice that are involved in the maintenance of pluripotency, male sexual development, and other processes. A recent paper in Cell has identified one member of this family, SOX17, as an essential factor for inducing the PGC lineage in humans. [2] Surprisingly, this protein does not appear to have a role in PGC specification in mice. This work not only introduces a new and important player to the field of germ cell specification, but also emphasizes the uniqueness of human PGC development compared to more extensively studied mouse models. PMID:25791734

  4. FGF, Insulin, and SMAD Signaling Cooperate for Avian Primordial Germ Cell Self-Renewal

    PubMed Central

    Whyte, Jemima; Glover, James D.; Woodcock, Mark; Brzeszczynska, Joanna; Taylor, Lorna; Sherman, Adrian; Kaiser, Pete; McGrew, Michael J.

    2015-01-01

    Summary Precise self-renewal of the germ cell lineage is fundamental to fertility and reproductive success. The early precursors for the germ lineage, primordial germ cells (PGCs), survive and proliferate in several embryonic locations during their migration to the embryonic gonad. By elucidating the active signaling pathways in migratory PGCs in vivo, we were able to create culture conditions that recapitulate this embryonic germ cell environment. In defined medium conditions without feeder cells, the growth factors FGF2, insulin, and Activin A, signaling through their cognate-signaling pathways, were sufficient for self-renewal of germline-competent PGCs. Forced expression of constitutively active MEK1, AKT, and SMAD3 proteins could replace their respective upstream growth factors. Unexpectedly, we found that BMP4 could replace Activin A in non-clonal growth conditions. These defined medium conditions identify the key molecular pathways required for PGC self-renewal and will facilitate efforts in biobanking of chicken genetic resources and genome editing. PMID:26677769

  5. Interspecific Germline Transmission of Cultured Primordial Germ Cells

    PubMed Central

    van de Lavoir, Marie-Cecile; Collarini, Ellen J.; Leighton, Philip A.; Fesler, Jeffrey; Lu, Daniel R.; Harriman, William D.; Thiyagasundaram, T. S.; Etches, Robert J.

    2012-01-01

    In birds, the primordial germ cell (PGC) lineage separates from the soma within 24 h following fertilization. Here we show that the endogenous population of about 200 PGCs from a single chicken embryo can be expanded one million fold in culture. When cultured PGCs are injected into a xenogeneic embryo at an equivalent stage of development, they colonize the testis. At sexual maturity, these donor PGCs undergo spermatogenesis in the xenogeneic host and become functional sperm. Insemination of semen from the xenogeneic host into females from the donor species produces normal offspring from the donor species. In our model system, the donor species is chicken (Gallus domesticus) and the recipient species is guinea fowl (Numida meleagris), a member of a different avian family, suggesting that the mechanisms controlling proliferation of the germline are highly conserved within birds. From a pragmatic perspective, these data are the basis of a novel strategy to produce endangered species of birds using domesticated hosts that are both tractable and fecund. PMID:22629301

  6. Improvement of Chicken Primordial Germ Cell Maintenance In Vitro by Blockade of the Aryl Hydrocarbon Receptor Endogenous Activity.

    PubMed

    Pérez Sáez, Juan M; Bussmann, Leonardo E; Barañao, J Lino; Bussmann, Ursula A

    2016-06-01

    Primordial germ cells (PGCs) are the undifferentiated progenitors of gametes. Germline competent PGCs can be developed as a cell-based system for genetic modification in chickens, which provides a valuable tool for transgenic technology with both research and industrial applications. This implies manipulation of PGCs, which, in recent years, encouraged a lot of research focused on the study of PGCs and the way of improving their culture. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that besides mediating toxic responses to environmental contaminants plays pivotal physiological roles in various biological processes. Since a novel compound that acts as an antagonist of this receptor has been reported to promote expansion of hematopoietic stem cells, we conducted the present study with the aim of determining whether addition of an established AHR antagonist to the standard culture medium used nowadays for in vitro chicken PGCs culture improves ex vivo expansion. We have found that addition of α-naphthoflavone in culture medium promotes the amplification of undifferentiated cells and that this effect is exerted by the blockade of AHR action. Our results constitute the first report of the successful use of a readily available AHR antagonist to improve avian PGCs expansion, and they further extend the knowledge of the effects of AHR modulation in undifferentiated cells. PMID:27253627

  7. Neurl4 contributes to germ cell formation and integrity in Drosophila

    PubMed Central

    Jones, Jennifer; Macdonald, Paul M.

    2015-01-01

    ABSTRACT Primordial germ cells (PGCs) form at the posterior pole of the Drosophila embryo, and then migrate to their final destination in the gonad where they will produce eggs or sperm. Studies of the different stages in this process, including assembly of germ plasm in the oocyte during oogenesis, specification of a subset of syncytial embryonic nuclei as PGCs, and migration, have been informed by genetic analyses. Mutants have defined steps in the process, and the identities of the affected genes have suggested biochemical mechanisms. Here we describe a novel PGC phenotype. When Neurl4 activity is reduced, newly formed PGCs frequently adopt irregular shapes and appear to bud off vesicles. PGC number is also reduced, an effect exacerbated by a separate role for Neurl4 in germ plasm formation during oogenesis. Like its mammalian homolog, Drosophila Neurl4 protein is concentrated in centrosomes and downregulates centrosomal protein CP110. Reducing CP110 activity suppresses the abnormal PGC morphology of Neurl4 mutants. These results extend prior analyses of Neurl4 in cultured cells, revealing a heightened requirement for Neurl4 in germ-line cells in Drosophila. PMID:26116656

  8. The mouse dead-end gene isoform alpha is necessary for germ cell and embryonic viability.

    PubMed

    Bhattacharya, Chitralekha; Aggarwal, Sita; Zhu, Rui; Kumar, Madhu; Zhao, Ming; Meistrich, Marvin L; Matin, Angabin

    2007-03-30

    Inactivation of the dead-end (Dnd1) gene in the Ter mouse strain results in depletion of primordial germ cells (PGCs) so that mice become sterile. However, on the 129 mouse strain background, loss of Dnd1 also increases testicular germ cell tumor incidence in parallel to PGC depletion. We report that inactivation of Dnd1 also affects embryonic viability in the 129 strain. Mouse Dnd1 encodes two protein isoforms, DND1-isoform alpha (DND1-alpha) and DND1-isoform beta (DND1-beta). Using isoform-specific antibodies, we determined DND1-alpha is expressed in embryos and embryonic gonads whereas DND1-beta expression is restricted to germ cells of the adult testis. Our data implicate DND1-alpha isoform to be necessary for germ cell viability and therefore its loss in Ter mice results in PGC depletion, germ cell tumor development and partial embryonic lethality in the 129 strain. PMID:17291453

  9. Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggs

    NASA Technical Reports Server (NTRS)

    Wakahara, M.; Neff, A. W.; Malacinski, G. M.

    1984-01-01

    Inverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.

  10. Primordial germ cells in the dorsal mesentery of the chicken embryo demonstrate left–right asymmetry and polarized distribution of the EMA1 epitope

    PubMed Central

    Hen, Gideon; Friedman-Einat, Miriam; Sela-Donenfeld, Dalit

    2014-01-01

    Despite the importance of the chicken as a model system, our understanding of the development of chicken primordial germ cells (PGCs) is far from complete. Here we characterized the morphology of PGCs at different developmental stages, their migration pattern in the dorsal mesentery of the chicken embryo, and the distribution of the EMA1 epitope on PGCs. The spatial distribution of PGCs during their migration was characterized by immunofluorescence on whole-mounted chicken embryos and on paraffin sections, using EMA1 and chicken vasa homolog antibodies. While in the germinal crescent PGCs were rounded and only 25% of them were labeled by EMA1, often seen as a concentrated cluster on the cell surface, following extravasation and migration in the dorsal mesentery PGCs acquired an elongated morphology, and 90% exhibited EMA1 epitope, which was concentrated at the tip of the pseudopodia, at the contact sites between neighboring PGCs. Examination of PGC migration in the dorsal mesentery of Hamburger and Hamilton stage 20–22 embryos demonstrated a left–right asymmetry, as migration of cells toward the genital ridges was usually restricted to the right, rather than the left, side of the mesentery. Moreover, an examination of another group of cells that migrate through the dorsal mesentery, the enteric neural crest cells, revealed a similar preference for the right side of the mesentery, suggesting that the migratory pathway of PGCs is dictated by the mesentery itself. Our findings provide new insights into the migration pathway of PGCs in the dorsal mesentery, and suggest a link between EMA1, PGC migration and cell–cell interactions. These findings may contribute to a better understanding of the mechanism underlying migration of PGCs in avians. PMID:24697411

  11. [Mediastinal germ cell tumors].

    PubMed

    Bremmer, F; Ströbel, P

    2016-09-01

    The mediastinum is among the most frequent anatomic region in which germ cell tumors (GCT) arise, second only to the gonads. Mediastinal GCT (mGCT) account for 16 % of all mediastinal neoplasms. Although the morphology and (according to all available data) the molecular genetics of mediastinal and gonadal GCT are identical, a number of unique aspects exist. There is a highly relevant bi-modal age distribution. In pre-pubertal children of both sexes, mGCT consist exclusively of teratomas and yolk sac tumors. The prognosis is generally favorable with modern treatment. In post-pubertal adults, virtually all patients with malignant mGCT are males; the prognosis is more guarded and depends (among other factors) on the histological GCT components and is similar to GCT in other organs. So-called somatic type malignancies (i. e. clonally related, non-germ cell neoplasias arising in a GCT) are much more frequent in mGCT than in other organs, and the association between mediastinal yolk sac tumors and hematological malignancies, such as myelodysplasias and leukemias, is unique to mediastinal tumors. The prognosis of GCT with somatic type malignancies is generally dismal. PMID:27491549

  12. Primordial germ cell migration in the yellowtail kingfish (Seriola lalandi) and identification of stromal cell-derived factor 1.

    PubMed

    Fernández, J A; Bubner, E J; Takeuchi, Y; Yoshizaki, G; Wang, T; Cummins, S F; Elizur, A

    2015-03-01

    Primordial germ cells (PGCs) are progenitors of the germ cell lineage, giving rise to either spermatogonia or oogonia after the completion of gonadal differentiation. Currently, there is little information on the mechanism of PGCs migration leading to the formation of the primordial gonad in perciform fish. Yellowtail kingfish (Seriola lalandi) (YTK) (order Perciforms) inhabit tropical and temperate waters in the southern hemisphere. Fundamental details into the molecular basis of larval development in this species can be easily studied in Australia, as they are commercially cultured and readily available. In this study, histological analysis of YTK larvae revealed critical time points for the migration of PGCs to the genital ridge, resulting in the subsequent development of the primordial gonad. In YTK larvae at 3, 5, 7 and 10 days post hatch (DPH), PGCs were not yet enclosed by somatic cells, indicating the primordial gonad had not yet started to form. While at 15, 18 and 20 DPH PGCs had already settled at the genital ridge and started to become enclosed by somatic cells indicating the primordial gonad had started to develop. A higher number of PGCs were observed in the larvae at 15 and 18 DPH indicating PGCs proliferation, which corresponds with them becoming enclosed by the somatic cells. Directional migration of PGCs toward the genital ridge is a critical event in the subsequent development of a gonad. In zebrafish, mouse and chicken, stromal-cell derived factor (SDF1) signalling is one of the key molecules for PGC migration. We subsequently isolated from YTK the SDF1 (Slal-SDF1) gene, which encodes for a 98-residue precursor protein with a signal peptide at the N-terminus. There is spatial conservation between fish species of four cysteine residues at positions C9, C11, C34 and C49, expected to form disulphide bonds and stabilize the SDF structure. In YTK, Slal-SDF1 gene expression analyses shows that this gene is expressed in larvae from 1 to 22 DPH and

  13. Germ Cell Segregation from the Drosophila Soma Is Controlled by an Inhibitory Threshold Set by the Arf-GEF Steppke

    PubMed Central

    Lee, Donghoon M.; Wilk, Ronit; Hu, Jack; Krause, Henry M.; Harris, Tony J. C.

    2015-01-01

    Germline cells segregate from the soma to maintain their totipotency, but the cellular mechanisms of this segregation are unclear. The Drosophila melanogaster embryo forms a posterior group of primordial germline cells (PGCs) by their division from the syncytial soma. Extended plasma membrane furrows enclose the PGCs in response to the germ plasm protein Germ cell-less (Gcl) and Rho1–actomyosin activity. Recently, we found that loss of the Arf-GEF Steppke (Step) leads to similar Rho1-dependent plasma membrane extensions but from pseudocleavage furrows of the soma. Here, we report that the loss of step also leads to premature formation of a large cell group at the anterior pole of the embryo . These anterior cells lacked germ plasm, but budded and formed at the same time as posterior PGCs, and then divided asynchronously as PGCs also do. With genetic analyses we found that Step normally activates Arf small G proteins and antagonizes Rho1–actomyosin pathways to inhibit anterior cell formation. A uniform distribution of step mRNA around the one-cell embryo cortex suggested that Step restricts cell formation through a global control mechanism. Thus, we examined the effect of Step on PGC formation at the posterior pole. Reducing Gcl or Rho1 levels decreased PGC numbers, but additional step RNAi restored their numbers. Reciprocally, GFP–Step overexpression induced dosage- and Arf-GEF-dependent loss of PGCs, an effect worsened by reducing Gcl or actomyosin pathway activity. We propose that a global distribution of Step normally sets an inhibitory threshold for Rho1 activity to restrict early cell formation to the posterior. PMID:25971667

  14. Perchlorate Exposure Reduces Primordial Germ Cell Number in Female Threespine Stickleback

    PubMed Central

    Petersen, Ann M.; Earp, Nathanial C.; Redmond, Mandy E.; Postlethwait, John H.; von Hippel, Frank A.; Buck, C. Loren; Cresko, William A.

    2016-01-01

    Perchlorate is a common aquatic contaminant that has long been known to affect thyroid function in vertebrates, including humans. More recently perchlorate has been shown to affect primordial sexual differentiation in the aquatic model fishes zebrafish and threespine stickleback, but the mechanism has been unclear. Stickleback exposed to perchlorate from fertilization have increased androgen levels in the embryo and disrupted reproductive morphologies as adults, suggesting that perchlorate could disrupt the earliest stages of primordial sexual differentiation when primordial germ cells (PGCs) begin to form the gonad. Female stickleback have three to four times the number of PGCs as males during the first weeks of development. We hypothesized that perchlorate exposure affects primordial sexual differentiation by reducing the number of germ cells in the gonad during an important window of stickleback sex determination at 14–18 days post fertilization (dpf). We tested this hypothesis by quantifying the number of PGCs at 16 dpf in control and 100 mg/L perchlorate-treated male and female stickleback. Perchlorate exposure from the time of fertilization resulted in significantly reduced PGC number only in genotypic females, suggesting that the masculinizing effects of perchlorate observed in adult stickleback may result from early changes to the number of PGCs at a time critical for sex determination. To our knowledge, this is the first evidence of a connection between an endocrine disruptor and reduction in PGC number prior to the first meiosis during sex determination. These findings suggest that a mode of action of perchlorate on adult reproductive phenotypes in vertebrates, including humans, such as altered fecundity and sex reversal or intersex gonads, may stem from early changes to germ cell development. PMID:27383240

  15. Primordial germ cell migration in the chick and mouse embryo: the role of the chemokine SDF-1/CXCL12.

    PubMed

    Stebler, Jürg; Spieler, Derek; Slanchev, Krasimir; Molyneaux, Kathleen A; Richter, Ulrike; Cojocaru, Vlad; Tarabykin, Victor; Wylie, Chris; Kessel, Michael; Raz, Erez

    2004-08-15

    As in many other animals, the primordial germ cells (PGCs) in avian and reptile embryos are specified in positions distinct from the positions where they differentiate into sperm and egg. Unlike in other organism however, in these embryos, the PGCs use the vascular system as a vehicle to transport them to the region of the gonad where they exit the blood vessels and reach their target. To determine the molecular mechanisms governing PGC migration in these species, we have investigated the role of the chemokine stromal cell-derived factor-1 (SDF-1/CXCL12) in guiding the cells towards their target in the chick embryo. We show that sdf-1 mRNA is expressed in locations where PGCs are found and towards which they migrate at the time they leave the blood vessels. Ectopically expressed chicken SDF-1alpha led to accumulation of PGCs at those positions. This analysis, as well as analysis of gene expression and PGC behavior in the mouse embryo, suggest that in both organisms, SDF-1 functions during the second phase of PGC migration, and not at earlier phases. These findings suggest that SDF-1 is required for the PGCs to execute the final migration steps as they transmigrate through the blood vessel endothelium of the chick or the gut epithelium of the mouse. PMID:15282153

  16. DAZL limits pluripotency, differentiation, and apoptosis in developing primordial germ cells.

    PubMed

    Chen, Hsu-Hsin; Welling, Maaike; Bloch, Donald B; Muñoz, Javier; Mientjes, Edwin; Chen, Xinjie; Tramp, Cody; Wu, Jie; Yabuuchi, Akiko; Chou, Yu-Fen; Buecker, Christa; Krainer, Adrian; Willemsen, Rob; Heck, Albert J; Geijsen, Niels

    2014-11-11

    The scarcity of primordial germ cells (PGCs) in the developing mammalian embryo hampers robust biochemical analysis of the processes that underlie early germ cell formation. Here, we demonstrate that DAZL, a germ cell-specific RNA binding protein, is a robust PGC marker during in vitro germ cell development. Using Dazl-GFP reporter ESCs, we demonstrate that DAZL plays a central role in a large mRNA/protein interactive network that blocks the translation of core pluripotency factors, including Sox2 and Sall4, as well as of Suz12, a polycomb family member required for differentiation of pluripotent cells. Thus, DAZL limits both pluripotency and somatic differentiation in nascent PGCs. In addition, we observed that DAZL associates with mRNAs of key Caspases and similarly inhibits their translation. This elegant fail-safe mechanism ensures that, whereas loss of DAZL results in prolonged expression of pluripotency factors, teratoma formation is avoided due to the concomitant activation of the apoptotic cascade. PMID:25418731

  17. Palifosfamide in Treating Patients With Recurrent Germ Cell Tumors

    ClinicalTrials.gov

    2015-06-11

    Adult Central Nervous System Germ Cell Tumor; Adult Teratoma; Malignant Extragonadal Germ Cell Tumor; Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Extragonadal Seminoma; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

  18. PRMT5 Protects Genomic Integrity during Global DNA Demethylation in Primordial Germ Cells and Preimplantation Embryos

    PubMed Central

    Kim, Shinseog; Günesdogan, Ufuk; Zylicz, Jan J.; Hackett, Jamie A.; Cougot, Delphine; Bao, Siqin; Lee, Caroline; Dietmann, Sabine; Allen, George E.; Sengupta, Roopsha; Surani, M. Azim

    2014-01-01

    Summary Primordial germ cells (PGCs) and preimplantation embryos undergo epigenetic reprogramming, which includes comprehensive DNA demethylation. We found that PRMT5, an arginine methyltransferase, translocates from the cytoplasm to the nucleus during this process. Here we show that conditional loss of PRMT5 in early PGCs causes complete male and female sterility, preceded by the upregulation of LINE1 and IAP transposons as well as activation of a DNA damage response. Similarly, loss of maternal-zygotic PRMT5 also leads to IAP upregulation. PRMT5 is necessary for the repressive H2A/H4R3me2s chromatin modification on LINE1 and IAP transposons in PGCs, directly implicating this modification in transposon silencing during DNA hypomethylation. PRMT5 translocates back to the cytoplasm subsequently, to participate in the previously described PIWI-interacting RNA (piRNA) pathway that promotes transposon silencing via de novo DNA remethylation. Thus, PRMT5 is directly involved in genome defense during preimplantation development and in PGCs at the time of global DNA demethylation. PMID:25457166

  19. Conceptual links between DNA methylation reprogramming in the early embryo and primordial germ cells.

    PubMed

    Seisenberger, Stefanie; Peat, Julian R; Reik, Wolf

    2013-06-01

    DNA methylation is a carrier of important regulatory information that undergoes global reprogramming in the mammalian germ line, including pre-implantation embryos and primordial germ cells (PGCs). A flurry of recent studies have employed technical advances to generate global profiles of methylation and hydroxymethylation in these cells, unravelling the dynamics of methylation erasure at single locus resolution. Active demethylation in the zygote, involving extensive oxidation, is followed by passive loss over early cell divisions. Certain gamete-contributed methylation marks appear to have evolved non-canonical mechanisms for targeted maintenance of methylation in the face of these processes. These protected sequences include the imprinting control regions (ICRs) required for parental imprinting but also a surprising number of other regions. Such targeted maintenance mechanisms may also operate at certain sequences during early PGC migration when global passive demethylation occurs. In later gonadal PGCs, imprints must be reset and this may be achieved through the targeting of active mechanisms including oxidation. Thus, emerging evidence paints a complex picture whereby active and passive demethylation pathways operate synergistically and in parallel to ensure robust erasure in the early embryo and PGCs. PMID:23510682

  20. Exome Sequencing of Bilateral Testicular Germ Cell Tumors Suggests Independent Development Lineages12

    PubMed Central

    Brabrand, Sigmund; Johannessen, Bjarne; Axcrona, Ulrika; Kraggerud, Sigrid M.; Berg, Kaja G.; Bakken, Anne C.; Bruun, Jarle; Fosså, Sophie D.; Lothe, Ragnhild A.; Lehne, Gustav; Skotheim, Rolf I.

    2015-01-01

    Intratubular germ cell neoplasia, the precursor of testicular germ cell tumors (TGCTs), is hypothesized to arise during embryogenesis from developmentally arrested primordial germ cells (PGCs) or gonocytes. In early embryonal life, the PGCs migrate from the yolk sac to the dorsal body wall where the cell population separates before colonizing the genital ridges. However, whether the malignant transformation takes place before or after this separation is controversial. We have explored the somatic exome-wide mutational spectra of bilateral TGCT to provide novel insight into the in utero critical time frame of malignant transformation and TGCT pathogenesis. Exome sequencing was performed in five patients with bilateral TGCT (eight tumors), of these three patients in whom both tumors were available (six tumors) and two patients each with only one available tumor (two tumors). Selected loci were explored by Sanger sequencing in 71 patients with bilateral TGCT. From the exome-wide mutational spectra, no identical mutations in any of the three bilateral tumor pairs were identified. Exome sequencing of all eight tumors revealed 87 somatic non-synonymous mutations (median 10 per tumor; range 5-21), some in already known cancer genes such as CIITA, NEB, platelet-derived growth factor receptor α (PDGFRA), and WHSC1. SUPT6H was found recurrently mutated in two tumors. We suggest independent development lineages of bilateral TGCT. Thus, malignant transformation into intratubular germ cell neoplasia is likely to occur after the migration of PGCs. We reveal possible drivers of TGCT pathogenesis, such as mutated PDGFRA, potentially with therapeutic implications for TGCT patients. PMID:25748235

  1. Exome sequencing of bilateral testicular germ cell tumors suggests independent development lineages.

    PubMed

    Brabrand, Sigmund; Johannessen, Bjarne; Axcrona, Ulrika; Kraggerud, Sigrid M; Berg, Kaja G; Bakken, Anne C; Bruun, Jarle; Fosså, Sophie D; Lothe, Ragnhild A; Lehne, Gustav; Skotheim, Rolf I

    2015-02-01

    Intratubular germ cell neoplasia, the precursor of testicular germ cell tumors (TGCTs), is hypothesized to arise during embryogenesis from developmentally arrested primordial germ cells (PGCs) or gonocytes. In early embryonal life, the PGCs migrate from the yolk sac to the dorsal body wall where the cell population separates before colonizing the genital ridges. However, whether the malignant transformation takes place before or after this separation is controversial. We have explored the somatic exome-wide mutational spectra of bilateral TGCT to provide novel insight into the in utero critical time frame of malignant transformation and TGCT pathogenesis. Exome sequencing was performed in five patients with bilateral TGCT (eight tumors), of these three patients in whom both tumors were available (six tumors) and two patients each with only one available tumor (two tumors). Selected loci were explored by Sanger sequencing in 71 patients with bilateral TGCT. From the exome-wide mutational spectra, no identical mutations in any of the three bilateral tumor pairs were identified. Exome sequencing of all eight tumors revealed 87 somatic non-synonymous mutations (median 10 per tumor; range 5-21), some in already known cancer genes such as CIITA, NEB, platelet-derived growth factor receptor α (PDGFRA), and WHSC1. SUPT6H was found recurrently mutated in two tumors. We suggest independent development lineages of bilateral TGCT. Thus, malignant transformation into intratubular germ cell neoplasia is likely to occur after the migration of PGCs. We reveal possible drivers of TGCT pathogenesis, such as mutated PDGFRA, potentially with therapeutic implications for TGCT patients. PMID:25748235

  2. Germline Gene Editing in Chickens by Efficient CRISPR-Mediated Homologous Recombination in Primordial Germ Cells

    PubMed Central

    Dimitrov, Lazar; Pedersen, Darlene; Ching, Kathryn H.; Yi, Henry; Collarini, Ellen J.; Izquierdo, Shelley; van de Lavoir, Marie-Cecile; Leighton, Philip A.

    2016-01-01

    The CRISPR/Cas9 system has been applied in a large number of animal and plant species for genome editing. In chickens, CRISPR has been used to knockout genes in somatic tissues, but no CRISPR-mediated germline modification has yet been reported. Here we use CRISPR to target the chicken immunoglobulin heavy chain locus in primordial germ cells (PGCs) to produce transgenic progeny. Guide RNAs were co-transfected with a donor vector for homology-directed repair of the double-strand break, and clonal populations were selected. All of the resulting drug-resistant clones contained the correct targeting event. The targeted cells gave rise to healthy progeny containing the CRISPR-targeted locus. The results show that gene-edited chickens can be obtained by modifying PGCs in vitro with the CRISPR/Cas9 system, opening up many potential applications for efficient genetic modification in birds. PMID:27099923

  3. Germline Gene Editing in Chickens by Efficient CRISPR-Mediated Homologous Recombination in Primordial Germ Cells.

    PubMed

    Dimitrov, Lazar; Pedersen, Darlene; Ching, Kathryn H; Yi, Henry; Collarini, Ellen J; Izquierdo, Shelley; van de Lavoir, Marie-Cecile; Leighton, Philip A

    2016-01-01

    The CRISPR/Cas9 system has been applied in a large number of animal and plant species for genome editing. In chickens, CRISPR has been used to knockout genes in somatic tissues, but no CRISPR-mediated germline modification has yet been reported. Here we use CRISPR to target the chicken immunoglobulin heavy chain locus in primordial germ cells (PGCs) to produce transgenic progeny. Guide RNAs were co-transfected with a donor vector for homology-directed repair of the double-strand break, and clonal populations were selected. All of the resulting drug-resistant clones contained the correct targeting event. The targeted cells gave rise to healthy progeny containing the CRISPR-targeted locus. The results show that gene-edited chickens can be obtained by modifying PGCs in vitro with the CRISPR/Cas9 system, opening up many potential applications for efficient genetic modification in birds. PMID:27099923

  4. Damaging effects of polychlorinated biphenyls on chicken primordial germ cells.

    PubMed

    Fang, Changge; Zhang, Caiqiao; Xia, Guoliang; Yang, Wei

    2002-01-01

    This work describes the effects of a commercial polychlorinated biphenyl (PCB) mixture, Aroclor 1254, as well as 17beta-oestradiol (E2) and testosterone on numbers and histomorphological changes of primordial germ cells (PGCs) in gonadal regions of Day 5 Hyline chicken embryos. The oestrogen receptor antagonist, clomiphen, alone or with PCBs was used in an attempt to protect the developing gonad from oestrogen-like effects of chemical PCBs. The results were as follows: (i) PCBs delayed embryonic development independently of dose (1 microg/egg, P<0.05; 10 microg/egg, P<0.01; 100 microg/egg, P<0.001 v. the control) and caused a dose-independent increase in mortality compared with the control group (10 microg/egg, P<0.01; 100 microg/egg, P<0.05); maximal mortality was observed in the 1 microg/egg group (P<0.001); (ii) PCBs decreased PGC numbers dose dependently (P<0.001) and caused a swollen nucleus with hyperchromatism (pyknosis) or cytoplasm vacuolation as signs of gonadal PGC degeneration in all PCB groups, or even complete disappearance in the 100 microg/egg group; (iii) after PCB treatment, the index of gonadal lesion increased significantly with the decrease of gonadal PGC number (1, 10 and 100 microg/egg, P<0.001); (iv) there were no observed effects of E2, testosterone and clomiphen on PGCs in the experiments; and (v) clomiphen failed to block the damaging effects of PCBs. These results suggest that the adverse effects of PCBs on chicken gonadal and germ cell development were initiated during the early stages of incubation through direct toxic effects, rather than through oestrogen-mimicking actions. As PGC numbers in the gonads decrease and the index of gonadal lesion increases, one may expect reproductive function to be compromised. PMID:12219939

  5. New perspective on molecular markers as promising therapeutic targets in germ cell tumors.

    PubMed

    Chieffi, Paolo

    2016-05-01

    Testicular germ cell tumors (TGCTs) are the most frequent solid malignant tumors in men 20-40 years of age and the most frequent cause of death from solid tumors in this age group. TGCTs comprise two major histologic groups: seminomas and non-seminomas germ cell tumors (NSGCTs). NSGCTs can be further divided into embryonal carcinoma, Teratoma, yolk sac tumor, and choriocarcinoma. Seminomas and NSGCTs present significant differences in clinical features, therapy, and prognosis, and both show characteristics of the Primordial Germ Cells (PGCs). Many discovered biomarkers including HMGA1, GPR30, Aurora-B, estrogen receptor β, and others have given further advantages to discriminate between histological subgroups and could represent useful therapeutic targets. PMID:27195201

  6. New perspective on molecular markers as promising therapeutic targets in germ cell tumors

    PubMed Central

    Chieffi, Paolo

    2016-01-01

    Summary Testicular germ cell tumors (TGCTs) are the most frequent solid malignant tumors in men 20–40 years of age and the most frequent cause of death from solid tumors in this age group. TGCTs comprise two major histologic groups: seminomas and non-seminomas germ cell tumors (NSGCTs). NSGCTs can be further divided into embryonal carcinoma, Teratoma, yolk sac tumor, and choriocarcinoma. Seminomas and NSGCTs present significant differences in clinical features, therapy, and prognosis, and both show characteristics of the Primordial Germ Cells (PGCs). Many discovered biomarkers including HMGA1, GPR30, Aurora-B, estrogen receptor β, and others have given further advantages to discriminate between histological subgroups and could represent useful therapeutic targets. PMID:27195201

  7. Expression of BLIMP1/PRMT5 and concurrent histone H2A/H4 arginine 3 dimethylation in fetal germ cells, CIS/IGCNU and germ cell tumors

    PubMed Central

    Eckert, Dawid; Biermann, Katharina; Nettersheim, Daniel; Gillis, Ad JM; Steger, Klaus; Jäck, Hans-Martin; Müller, Annette M; Looijenga, Leendert HJ; Schorle, Hubert

    2008-01-01

    Background Most testicular germ cell tumors arise from intratubular germ cell neoplasia unclassified (IGCNU, also referred to as carcinoma in situ), which is thought to originate from a transformed primordial germ cell (PGC)/gonocyte, the fetal germ cell. Analyses of the molecular profile of IGCNU and seminoma show similarities to the expression profile of fetal germ cells/gonocytes. In murine PGCs, expression and interaction of Blimp1 and Prmt5 results in arginine 3 dimethylation of histone H2A and H4. This imposes epigenetic modifications leading to transcriptional repression in mouse PGCs enabling them to escape the somatic differentiation program during migration, while expressing markers of pluripotency. Results In the present study, we show that BLIMP1 and PRMT5 were expressed and arginine dimethylation of histones H2A and H4 was detected in human male gonocytes at weeks 12–19 of gestation, indicating a role of this mechanism in human fetal germ cell development as well. Moreover, BLIMP1/PRMT5 and histone H2A and H4 arginine 3 dimethylation was present in IGCNU and most seminomas, while downregulated in embryonal carcinoma (EC) and other nonseminomatous tumors. Conclusion These data reveal similarities in marker expression and histone modification between murine and human PGCs. Moreover, we speculate that the histone H2A and H4 arginine 3 dimethylation might be the mechanism by which IGCNU and seminoma maintain the undifferentiated state while loss of these histone modifications leads to somatic differentiation observed in nonseminomatous tumors. PMID:18992153

  8. Erasure of DNA methylation, genomic imprints, and epimutations in a primordial germ-cell model derived from mouse pluripotent stem cells

    PubMed Central

    Miyoshi, Norikatsu; Stel, Jente M.; Shioda, Keiko; Qu, Na; Odahima, Junko; Mitsunaga, Shino; Zhang, Xiangfan; Nagano, Makoto; Hochedlinger, Konrad; Isselbacher, Kurt J.; Shioda, Toshi

    2016-01-01

    The genome-wide depletion of 5-methylcytosines (5meCs) caused by passive dilution through DNA synthesis without daughter strand methylation and active enzymatic processes resulting in replacement of 5meCs with unmethylated cytosines is a hallmark of primordial germ cells (PGCs). Although recent studies have shown that in vitro differentiation of pluripotent stem cells (PSCs) to PGC-like cells (PGCLCs) mimics the in vivo differentiation of epiblast cells to PGCs, how DNA methylation status of PGCLCs resembles the dynamics of 5meC erasure in embryonic PGCs remains controversial. Here, by differential detection of genome-wide 5meC and 5-hydroxymethylcytosine (5hmeC) distributions by deep sequencing, we show that PGCLCs derived from mouse PSCs recapitulated the process of genome-wide DNA demethylation in embryonic PGCs, including significant demethylation of imprint control regions (ICRs) associated with increased mRNA expression of the corresponding imprinted genes. Although 5hmeCs were also significantly diminished in PGCLCs, they retained greater amounts of 5hmeCs than intragonadal PGCs. The genomes of both PGCLCs and PGCs selectively retained both 5meCs and 5hmeCs at a small number of repeat sequences such as GSAT_MM, of which the significant retention of bisulfite-resistant cytosines was corroborated by reanalysis of previously published whole-genome bisulfite sequencing data for intragonadal PGCs. PSCs harboring abnormal hypermethylation at ICRs of the Dlk1-Gtl2-Dio3 imprinting cluster diminished these 5meCs upon differentiation to PGCLCs, resulting in transcriptional reactivation of the Gtl2 gene. These observations support the usefulness of PGCLCs in studying the germline epigenetic erasure including imprinted genes, epimutations, and erasure-resistant loci, which may be involved in transgenerational epigenetic inheritance. PMID:27486249

  9. General Information about Extragonadal Germ Cell Tumors

    MedlinePlus

    ... Germ Cell Tumors Treatment (PDQ®)–Patient Version General Information About Extragonadal Germ Cell Tumors Go to Health ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  10. General Information about Ovarian Germ Cell Tumors

    MedlinePlus

    ... Germ Cell Tumors Treatment (PDQ®)–Patient Version General Information About Ovarian Germ Cell Tumors Go to Health ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  11. HISTORY OF GERM CELL MUTAGENESIS

    EPA Science Inventory

    Much of the early work on germ cell mutation analysis was conducted with nonmammalian species, but this historical overview will begin with the rodent studies that provided quantitative data on induced mutations. The initial studies of mutation induction utilized the newly develo...

  12. Genome-wide analysis of the maternal-to-zygotic transition in Drosophila primordial germ cells

    PubMed Central

    2012-01-01

    Background During the maternal-to-zygotic transition (MZT) vast changes in the embryonic transcriptome are produced by a combination of two processes: elimination of maternally provided mRNAs and synthesis of new transcripts from the zygotic genome. Previous genome-wide analyses of the MZT have been restricted to whole embryos. Here we report the first such analysis for primordial germ cells (PGCs), the progenitors of the germ-line stem cells. Results We purified PGCs from Drosophila embryos, defined their proteome and transcriptome, and assessed the content, scale and dynamics of their MZT. Transcripts encoding proteins that implement particular types of biological functions group into nine distinct expression profiles, reflecting coordinate control at the transcriptional and posttranscriptional levels. mRNAs encoding germ-plasm components and cell-cell signaling molecules are rapidly degraded while new transcription produces mRNAs encoding the core transcriptional and protein synthetic machineries. The RNA-binding protein Smaug is essential for the PGC MZT, clearing transcripts encoding proteins that regulate stem cell behavior, transcriptional and posttranscriptional processes. Computational analyses suggest that Smaug and AU-rich element binding proteins function independently to control transcript elimination. Conclusions The scale of the MZT is similar in the soma and PGCs. However, the timing and content of their MZTs differ, reflecting the distinct developmental imperatives of these cell types. The PGC MZT is delayed relative to that in the soma, likely because relief of PGC-specific transcriptional silencing is required for zygotic genome activation as well as for efficient maternal transcript clearance. PMID:22348290

  13. Insulin-like growth factor receptor 1b is required for zebrafish primordial germ cell migration and survival

    PubMed Central

    Schlueter, Peter J.; Sang, Xianpeng; Duan, Cunming; Wood, Antony W.

    2007-01-01

    Insulin-like growth factor (IGF) signaling is a critical regulator of somatic growth during fetal and adult development, primarily through its stimulatory effects on cell proliferation and survival. IGF signaling is also required for development of the reproductive system, although its precise role in this regard remains unclear. We have hypothesized that IGF signaling is required for embryonic germline development, which requires the specification and proliferation of primordial germ cells (PGCs) in an extragonadal location, followed by directed migration to the genital ridges. We tested this hypothesis using loss-of-function studies in the zebrafish embryo, which possesses two functional copies of the Type-1 IGF receptor gene (igf1ra, igf1rb). Knockdown of IGF1Rb by morpholino oligonucleotides (MO) results in mismigration and elimination of primordial germ cells (PGCs), resulting in fewer PGCs colonizing the genital ridges. In contrast, knockdown of IGF1Ra has no effect on PGC migration or number despite inducing widespread somatic cell apoptosis. Ablation of both receptors, using combined MO injections or overexpression of a dominant-negative IGF1R, yields embryos with a PGC-deficient phenotype similar to IGF1Rb knockdown. TUNEL analyses revealed that mismigrated PGCs in IGF1Rb-deficient embryos are eliminated by apoptosis; overexpression of an antiapoptotic gene (Bcl2l) rescues ectopic PGCs from apoptosis but fails to rescue migration defects. Lastly, we show that suppression of IGF signaling leads to quantitative changes in the expression of genes encoding CXCL-family chemokine ligands and receptors involved in PGC migration. Collectively, these data suggest a novel role for IGF signaling in early germline development, potentially via cross-talk with chemokine signaling pathways. PMID:17362906

  14. SOX17 is a critical specifier of human primordial germ cell fate.

    PubMed

    Irie, Naoko; Weinberger, Leehee; Tang, Walfred W C; Kobayashi, Toshihiro; Viukov, Sergey; Manor, Yair S; Dietmann, Sabine; Hanna, Jacob H; Surani, M Azim

    2015-01-15

    Specification of primordial germ cells (PGCs) marks the beginning of the totipotent state. However, without a tractable experimental model, the mechanism of human PGC (hPGC) specification remains unclear. Here, we demonstrate specification of hPGC-like cells (hPGCLCs) from germline competent pluripotent stem cells. The characteristics of hPGCLCs are consistent with the embryonic hPGCs and a germline seminoma that share a CD38 cell-surface marker, which collectively defines likely progression of the early human germline. Remarkably, SOX17 is the key regulator of hPGC-like fate, whereas BLIMP1 represses endodermal and other somatic genes during specification of hPGCLCs. Notable mechanistic differences between mouse and human PGC specification could be attributed to their divergent embryonic development and pluripotent states, which might affect other early cell-fate decisions. We have established a foundation for future studies on resetting of the epigenome in hPGCLCs and hPGCs for totipotency and the transmission of genetic and epigenetic information. PMID:25543152

  15. Identification of Potential Germ-Cell Mutagens

    EPA Science Inventory

    The existence of agents that can induce germ-cell mutations in experimental systems has been recognized since 1927 with the discovery of the ability of X-rays to induce such mutations in Drosophila. Various rodent-based germ-cell mutation assays have been developed, and ~50 germ...

  16. The Ter Mutation In The Dead End Gene Causes Germ Cell Loss And Testicular Germ Cell Tumours

    SciTech Connect

    Youngren, Kirsten K.; Coveney, Douglas; Peng, Xiaoning; Bhattacharya, Chitralekha; Schmidt, Laura S.; Nickerson, Michael L.; Lamb, Bruce T.; Deng Jian Min; Behringer, Richard R.; Capel, Blanche; Rubin, Edward M.; Nadeau, Joseph H.; Matin, Angabin

    2005-01-01

    In mice, the Ter mutation causes primordial germ cell (PGC) loss in all genetic backgrounds1. Ter is also a potent modifier of spontaneous testicular germ cell tumour (TGCT) susceptibility in the 129 family of inbred strains, and markedly increases TGCT incidence in 129-Ter/Ter males2 4. In 129-Ter/Ter mice, some of the remaining PGCs transform into undifferentiated pluripotent embryonal carcinoma cells2 6, and after birth differentiate into various cells and tissues that compose TGCTs. Here, we report the positional cloning of Ter, revealing a point mutation that introduces a termination codon in the mouse orthologue (Dnd1) of the zebrafish dead end (dnd) gene. PGC deficiency is corrected both with bacterial artificial chromosomes that contain Dnd1 and with a Dnd1-encoding transgene. Dnd1 is expressed in fetal gonads during the critical period when TGCTs originate. DND1 has an RNA recognition motif and is most similar to the apobec complementation factor, a component of the cytidine t o uridine RNA-editing complex. These results suggest that Ter may adversely affect essential aspects of RNA biology during PGC development. DND1 is the first protein known to have an RNA recognition motif directly implicated as a heritable cause of spontaneous tumorigenesis. TGCT development in the 129-Ter mouse strain models paediatric TGCT in humans. This work will have important implications for our understanding of the genetic control of TGCT pathogenesis and PGC biology.

  17. Molecular and biological aspects of early germ cell development in interspecies hybrids between chickens and pheasants.

    PubMed

    Kang, Seok Jin; Sohn, Sea Hwan; Kang, Kyung Soo; Lee, Hyung Chul; Lee, Seul Ki; Choi, Jin Won; Han, Jae Yong

    2011-03-01

    Interspecific hybrids provide insights into fundamental genetic principles, and may prove useful for biotechnological applications and as tools for the conservation of endangered species. In the present study, interspecies hybrids were generated between the Korean ring-necked pheasant (Phasianus colchicus) and the White Leghorn chicken (Gallus gallus domesticus). We determined whether these hybrids were good recipients for the production of germline chimeric birds. PCR-based species-specific amplification and karyotype analyses showed that the hybrids inherited genetic material from both parents. Evaluation of biological function indicated that the growth rates of hybrids during the exponential phase (body weight/week) were similar to those of the pheasant but not the chicken, and that the incubation period for hatching was significantly different from that of both parents. Primordial germ cells (PGCs) of hybrids reacted with a pheasant PGC-specific antibody and circulated normally in blood vessels. The peak time of hybrid PGC migration was equivalent to that of the pheasant. In late embryonic stages, germ cells were detected by the QCR1 antibody on 15 d male gonads and were normally localized in the seminiferous cords. We examined the migration ability and developmental localization of exogenous PGCs transferred into the blood vessels of 63 h hybrid embryos. Donor-derived PGCs reacted with a donor-specific antibody were detected on 7 d gonads and the seminiferous tubules of hatchlings. Therefore, germ cell transfer into developing embryos of an interspecies hybrid can be efficiently used for the conservation of threatened animals and endangered species, and many biotechnological applications. PMID:21111472

  18. Primordial Germ Cell Specification and Migration

    PubMed Central

    Marlow, Florence

    2015-01-01

    Primordial germ cells are the progenitor cells that give rise to the gametes. In some animals, the germline is induced by zygotic transcription factors, whereas in others, primordial germ cell specification occurs via inheritance of maternally provided gene products known as germ plasm. Once specified, the primordial germ cells of some animals must acquire motility and migrate to the gonad in order to survive. In all animals examined, perinuclear structures called germ granules form within germ cells. This review focuses on some of the recent studies, conducted by several groups using diverse systems, from invertebrates to vertebrates, which have provided mechanistic insight into the molecular regulation of germ cell specification and migration. PMID:26918157

  19. A spindle-independent cleavage pathway controls germ cell formation in Drosophila.

    PubMed

    Cinalli, Ryan M; Lehmann, Ruth

    2013-07-01

    The primordial germ cells (PGCs) are the first cells to form during Drosophila melanogaster embryogenesis. Whereas the process of somatic cell formation has been studied in detail, the mechanics of PGC formation are poorly understood. Here, using four-dimensional multi-photon imaging combined with genetic and pharmacological manipulations, we find that PGC formation requires an anaphase spindle-independent cleavage pathway. In addition to using core regulators of cleavage, including the small GTPase RhoA (Drosophila rho1) and the Rho-associated kinase, ROCK (Drosophila drok), we show that this pathway requires Germ cell-less (GCL), a conserved BTB-domain protein not previously implicated in cleavage mechanics. This alternative form of cell formation suggests that organisms have evolved multiple molecular strategies for regulating the cytoskeleton during cleavage. PMID:23728423

  20. Targeted expression in zebrafish primordial germ cells by Cre/loxP and Gal4/UAS systems.

    PubMed

    Xiong, Feng; Wei, Zhi-Qiang; Zhu, Zuo-Yan; Sun, Yong-Hua

    2013-10-01

    In zebrafish and other vertebrates, primordial germ cells (PGCs) are a population of embryonic cells that give rise to sperm and eggs in adults. Any type of genetically manipulated lines have to be originated from the germ cells of the manipulated founders, thus it is of great importance to establish an effective technology for highly specific PGC-targeted gene manipulation in vertebrates. In the present study, we used the Cre/loxP recombinase system and Gal4/UAS transcription system for induction and regulation of mRFP (monomer red fluorescent protein) gene expression to achieve highly efficient PGC-targeted gene expression in zebrafish. First, we established two transgenic activator lines, Tg(kop:cre) and Tg(kop:KalTA4), to express the Cre recombinases and the Gal4 activator proteins in PGCs. Second, we generated two transgenic effector lines, Tg(kop:loxP-SV40-loxP-mRFP) and Tg(UAS:mRFP), which intrinsically showed transcriptional silence of mRFP. When Tg(kop:cre) females were crossed with Tg(kop:loxP-SV40-loxP-mRFP) males, the loxP flanked SV40 transcriptional stop sequence was 100 % removed from the germ cells of the transgenic hybrids. This led to massive production of PGC-specific mRFP transgenic line, Tg(kop:loxP-mRFP), from an mRFP silent transgenic line, Tg(kop:loxP-SV40-loxP-mRFP). When Tg(kop:KalTA4) females were crossed with Tg(UAS:mRFP) males, the hybrid embryos showed PGC specifically expressed mRFP from shield stage till 25 days post-fertilization (pf), indicating the high sensitivity, high efficiency, and long-lasting effect of the Gal4/UAS system. Real-time PCR analysis showed that the transcriptional amplification efficiency of the Gal4/UAS system in PGCs can be about 300 times higher than in 1-day-pf embryos. More importantly, when the UAS:mRFP-nos1 construct was directly injected into the Tg(kop:KalTA4) embryos, it was possible to specifically label the PGCs with high sensitivity, efficiency, and persistence. Therefore, we have established two

  1. [Ovarian germ cell tumors in girls].

    PubMed

    Nechushkina, I V; Karseladze, A I

    2015-01-01

    Morphological structure of tumor influences on the clinical course of the disease in children with germ cell tumors. Patients with ovarian dysgerminoma at the time of diagnosis are significantly older than patients with immature teratoma and yolk sac tumor. Immature teratoma and mixed germ cell tumors are significantly larger compared to other germ cell tumors. Yolk sac tumor and embryonal carcinoma are the most common cause of emergency surgical interventions and are accompanied by rupture of tumor capsule. PMID:26087605

  2. Germ cell binding to rat Sertoli cells in vitro

    SciTech Connect

    DePhilip, R.M.; Danahey, D.G.

    1987-12-01

    The interaction between male germ cells and Sertoli cells was studied in vitro by co-incubation experiments using isolated rat germ cells and primary cultures of Sertoli cells made germ cell-free by the differential sensitivity of germ cells to hypotonic shock. The germ cell/Sertoli cell interaction was examined morphologically with phase-contrast and scanning electron microscopy and then quantified by measuring radioactivity bound to Sertoli cell cultures after co-incubation with added (/sup 3/H)leucine-labeled germ cells. Germ cell binding to Sertoli cell cultures was the result of specific adhesion between these two cell types, and several features of this specific adhesion were observed. First, germ cells adhered to Sertoli cell cultures under conditions during which spleen cells and red blood cells did not. Second, germ cells had a greater affinity for Sertoli cell cultures than they had for cultures of testicular peritubular cells or cerebellar astrocytes. Third, germ cells fixed with paraformaldehyde adhered to live Sertoli cultures while similarly fixed spleen cells adhered less tightly. Neither live nor paraformaldehyde-fixed germ cells adhered to fixed Sertoli cell cultures. Fourth, germ cell binding to Sertoli cell cultures was not immediate but increased steadily and approached a maximum at 4 h of co-incubation. Saturation of germ cell binding to Sertoli cell cultures occurred when more than 4200 germ cells were added per mm2 of Sertoli cell culture surface. Finally, germ cell binding to Sertoli cell cultures was eliminated when co-incubation was performed on ice. Based on these observations, we concluded that germ cell adhesion to Sertoli cells was specific, temperature-dependent, and required a viable Sertoli cell but not necessarily a viable germ cell.

  3. Gradual recruitment and selective clearing generate germ plasm aggregates in the zebrafish embryo.

    PubMed

    Eno, Celeste; Pelegri, Francisco

    2013-01-01

    Determination of primordial germ cells (PGCs) is one of the earliest decisions in animal embryogenesis. In many species, PGCs are determined through maternally-inherited germ plasm ribonucleoparticles (RNPs). In zebrafish, these are transmitted during oogenesis as dispersed RNPs, which after fertilization multimerize and become recruited as large aggregates at furrows for the first and second cell cycles. Here, we show that the number of recruited germ plasm RNPs is halved every cell cycle. We also show that germ plasm RNPs are recruited during the third cell cycle, but only transiently. Our data support a mechanism in which systematic local gathering of germ plasm RNPs during cytokinesis and threshold-dependent clearing contribute to forming germ plasm aggregates with the highest RNP number and germ cell-inducing potential. PMID:24721731

  4. Hematopoietic activity in putative mouse primordial germ cell populations.

    PubMed

    Scaldaferri, Maria Lucia; Klinger, Francesca Gioia; Farini, Donatella; Di Carlo, Anna; Carsetti, Rita; Giorda, Ezio; De Felici, Massimo

    2015-05-01

    In the present paper, starting from the observation of heterogeneous expression of the GOF-18ΔPE-GFP Pou5f1 (Oct3/4) transgene in putative mouse PGC populations settled in the aorta-gonad-mesonephros (AGM) region, we identified various OCT3/4 positive populations showing distinct expression of PGC markers (BLIMP-1, AP, TG-1, STELLA) and co-expressing several proteins (CD-34, CD-41, FLK-1) and genes (Brachyury, Hox-B4, Scl/Tal-1 and Gata-2) of hematopoietic precursors. Moreover, we found that Oct3/4-GFP(weak) CD-34(weak/high) cells possess robust hematopoietic colony forming activity (CFU) in vitro. These data indicate that the cell population usually considered PGCs moving toward the gonadal ridges encompasses a subset of cells co-expressing several germ cell and hematopoietic markers and possessing hematopoietic activity. These results are discussed within of the current model of germline segregation. PMID:25684074

  5. Autonomy in specification of primordial germ cells and their passive translocation in the sea urchin.

    PubMed

    Yajima, Mamiko; Wessel, Gary M

    2012-10-01

    The process of germ line determination involves many conserved genes, yet is highly variable. Echinoderms are positioned at the base of Deuterostomia and are crucial to understanding these evolutionary transitions, yet the mechanism of germ line specification is not known in any member of the phyla. Here we demonstrate that small micromeres (SMics), which are formed at the fifth cell division of the sea urchin embryo, illustrate many typical features of primordial germ cell (PGC) specification. SMics autonomously express germ line genes in isolated culture, including selective Vasa protein accumulation and transcriptional activation of nanos; their descendants are passively displaced towards the animal pole by secondary mesenchyme cells and the elongating archenteron during gastrulation; Cadherin (G form) has an important role in their development and clustering phenotype; and a left/right integration into the future adult anlagen appears to be controlled by a late developmental mechanism. These results suggest that sea urchin SMics share many more characteristics typical of PGCs than previously thought, and imply a more widely conserved system of germ line development among metazoans. PMID:22991443

  6. Autonomy in specification of primordial germ cells and their passive translocation in the sea urchin

    PubMed Central

    Yajima, Mamiko; Wessel, Gary M.

    2012-01-01

    The process of germ line determination involves many conserved genes, yet is highly variable. Echinoderms are positioned at the base of Deuterostomia and are crucial to understanding these evolutionary transitions, yet the mechanism of germ line specification is not known in any member of the phyla. Here we demonstrate that small micromeres (SMics), which are formed at the fifth cell division of the sea urchin embryo, illustrate many typical features of primordial germ cell (PGC) specification. SMics autonomously express germ line genes in isolated culture, including selective Vasa protein accumulation and transcriptional activation of nanos; their descendants are passively displaced towards the animal pole by secondary mesenchyme cells and the elongating archenteron during gastrulation; Cadherin (G form) has an important role in their development and clustering phenotype; and a left/right integration into the future adult anlagen appears to be controlled by a late developmental mechanism. These results suggest that sea urchin SMics share many more characteristics typical of PGCs than previously thought, and imply a more widely conserved system of germ line development among metazoans. PMID:22991443

  7. Assessment of functional gametes in chickens after transfer of primordial germ cells.

    PubMed

    Petitte, J N; Clark, M E; Etches, R J

    1991-05-01

    The ability of primordial germ cells (PGCs) transferred from donor to recipient embryos to form functional gametes was assessed using feather colour as a phenotypic marker. Donor primordial germ cells were obtained in blood samples taken from Dwarf White Leghorn embryos, homozygous for the dominant allele at the locus for 'dominant white' plumage (I), which had been incubated for 52 h. Blood samples containing PGCs were transferred by intravascular injection to Barred Plymouth Rock embryos (ii) incubated for 53, 72 and 96 h. Of the embryos which hatched, 28 were male and 31 were female. All chicks were raised to sexual maturity and test mated with Barred Plymouth Rock fowl. All of the 3117 offspring exhibited the typical Barred Plymouth Rock phenotype; no Barred Plymouth Rock x Dwarf White Leghorn chicks were obtained. The results of this study suggest that the frequency of transmission of the donor line genotype after PGC transfer must be improved for this technique to be useful for the routine development of transgenic poultry. PMID:2056493

  8. Effects of specific and prolonged expression of zebrafish growth factors, Fgf2 and Lif in primordial germ cells in vivo

    SciTech Connect

    Wong, Ten-Tsao; Collodi, Paul

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer We discovered that nanos3 3 Prime UTR prolonged PGC-specific protein expression up to 26 days. Black-Right-Pointing-Pointer Expression of Fgf2 in PGCs significantly increased PGC number at later developmental stages. Black-Right-Pointing-Pointer Expression of Lif in PGCs resulted in a significant disruption of PGC migration. Black-Right-Pointing-Pointer Lif illicited its effect on PGC migration through Lif receptor a. Black-Right-Pointing-Pointer Our approach could be used to achieve prolonged PGC-specific expression of other proteins. -- Abstract: Primordial germ cells (PGCs), specified early in development, proliferate and migrate to the developing gonad before sexual differentiation occurs in the embryo and eventually give rise to spermatogonia or oogonia. In this study, we discovered that nanos3 3 Prime UTR, a common method used to label PGCs, not only directed PGC-specific expression of DsRed but also prolonged this expression up to 26 days post fertilization (dpf) when DsRed-nanos3 3 Prime UTR hybrid mRNAs were introduced into 1- to 2-cell-stage embryos. As such, we employed this knowledge to express zebrafish leukemia inhibitory factor (Lif), basic fibroblast growth factor (Fgf2) and bone morphogenetic protein 4 (Bmp4) in the PGCs and evaluate their effects on PGC development in vivo for over a period of 3 weeks. The results show that expression of Fgf2 significantly increased PGC number at 14- and 21-dpf while Bmp4 resulted in severe ventralization and death of the embryos by 3 days. Expression of Lif resulted in a significant disruption of PGC migration. Mopholino knockdown experiments indicated that Lif illicited its effect on PGC migration through Lif receptor a (Lifra) but not Lifrb. The general approach described in this study could be used to achieve prolonged PGC-specific expression of other proteins to investigate their roles in germ cell and gonad development. The results also indicate that zebrafish PGCs

  9. Treatment Option Overview (Extragonadal Germ Cell Tumors)

    MedlinePlus

    ... hCG and LDH may be at any level. Poor prognosis A nonseminoma extragonadal germ cell tumor is in the poor prognosis group if: the tumor is in the ... extragonadal germ cell tumor does not have a poor prognosis group. Treatment Option Overview Key Points There ...

  10. Dazl Functions in Maintenance of Pluripotency and Genetic and Epigenetic Programs of Differentiation in Mouse Primordial Germ Cells In Vivo and In Vitro

    PubMed Central

    Haston, Kelly M.; Tung, Joyce Y.; Reijo Pera, Renee A.

    2009-01-01

    Background Mammalian germ cells progress through a unique developmental program that encompasses proliferation and migration of the nascent primordial germ cell (PGC) population, reprogramming of nuclear DNA to reset imprinted gene expression, and differentiation of mature gametes. Little is known of the genes that regulate quantitative and qualitative aspects of early mammalian germ cell development both in vivo, and during differentiation of germ cells from mouse embryonic stem cells (mESCs) in vitro. Methodology and Principal Findings We used a transgenic mouse system that enabled isolation of small numbers of Oct4ΔPE:GFP-positive germ cells in vivo, and following differentiation from mESCs in vitro, to uncover quantitate and qualitative phenotypes associated with the disruption of a single translational regulator, Dazl. We demonstrate that disruption of Dazl results in a post-migratory, pre-meiotic reduction in PGC number accompanied by aberrant expression of pluripotency genes and failure to erase and re-establish genomic imprints in isolated male and female PGCs, as well as subsequent defect in progression through meiosis. Moreover, the phenotypes observed in vivo were mirrored by those in vitro, with inability of isolated mutant PGCs to establish pluripotent EG (embryonic germ) cell lines and few residual Oct-4-expressing cells remaining after somatic differentiation of mESCs carrying a Dazl null mutation. Finally, we observed that even within undifferentiated mESCs, a nascent germ cell subpopulation exists that was effectively eliminated with ablation of Dazl. Conclusions and Significance This report establishes the translational regulator Dazl as a component of pluripotency, genetic, and epigenetic programs at multiple time points of germ cell development in vivo and in vitro, and validates use of the ESC system to model and explore germ cell biology. PMID:19468308

  11. Germ cell quantitation in human testicular biopsy.

    PubMed

    Sinha Hikim, A P; Chakraborty, J; Jhunjhunwala, J S

    1985-01-01

    Quantitative analysis of human seminiferous epithelium was carried out using an improved method of glutaraldehyde and osmium fixation with plastic embedding. Part of each biopsy specimen was fixed in Bouin's fixative and embedded in paraffin for comparison. Epon embedded tissue had very little artifactual damage compared with paraffin embedded tissue sections. The germ cell to Sertoli cell ratios were determined by counting the various germ cells per "unit" tubular area. Data obtained by this method reflect a remarkable stability of Sertoli cell number and germ cell-Sertoli cell ratios both between biopsies from different individuals and between biopsies from right and left testes from the same individual. Agreement between the present results and those of earlier studies based on paraffin embedded testicular specimens supports the validity of this method of germ cell quantitation of human testicular biopsy samples. PMID:3927550

  12. Sex determination in mammalian germ cells

    PubMed Central

    Spiller, Cassy M; Bowles, Josephine

    2015-01-01

    Germ cells are the precursors of the sperm and oocytes and hence are critical for survival of the species. In mammals, they are specified during fetal life, migrate to the developing gonads and then undergo a critical period during which they are instructed, by the soma, to adopt the appropriate sexual fate. In a fetal ovary, germ cells enter meiosis and commit to oogenesis, whereas in a fetal testis, they avoid entry into meiosis and instead undergo mitotic arrest and mature toward spermatogenesis. Here, we discuss what we know so far about the regulation of sex-specific differentiation of germ cells, considering extrinsic molecular cues produced by somatic cells, as well as critical intrinsic changes within the germ cells. This review focuses almost exclusively on our understanding of these events in the mouse model. PMID:25791730

  13. The hedgehog Pathway Gene shifted Functions together with the hmgcr-Dependent Isoprenoid Biosynthetic Pathway to Orchestrate Germ Cell Migration

    PubMed Central

    Deshpande, Girish; Zhou, Keren; Wan, Joy Y.; Friedrich, Jana; Jourjine, Nicholas; Smith, Daniel; Schedl, Paul

    2013-01-01

    The Drosophila embryonic gonad is assembled from two distinct cell types, the Primordial Germ Cells (PGCs) and the Somatic Gonadal Precursor cells (SGPs). The PGCs form at the posterior of blastoderm stage embryos and are subsequently carried inside the embryo during gastrulation. To reach the SGPs, the PGCs must traverse the midgut wall and then migrate through the mesoderm. A combination of local repulsive cues and attractive signals emanating from the SGPs guide migration. We have investigated the role of the hedgehog (hh) pathway gene shifted (shf) in directing PGC migration. shf encodes a secreted protein that facilitates the long distance transmission of Hh through the proteoglycan matrix after it is released from basolateral membranes of Hh expressing cells in the wing imaginal disc. shf is expressed in the gonadal mesoderm, and loss- and gain-of-function experiments demonstrate that it is required for PGC migration. Previous studies have established that the hmgcr-dependent isoprenoid biosynthetic pathway plays a pivotal role in generating the PGC attractant both by the SGPs and by other tissues when hmgcr is ectopically expressed. We show that production of this PGC attractant depends upon shf as well as a second hh pathway gene gγ1. Further linking the PGC attractant to Hh, we present evidence indicating that ectopic expression of hmgcr in the nervous system promotes the release/transmission of the Hh ligand from these cells into and through the underlying mesodermal cell layer, where Hh can contact migrating PGCs. Finally, potentiation of Hh by hmgcr appears to depend upon cholesterol modification. PMID:24068944

  14. Dissecting Germ Cell Metabolism through Network Modeling

    PubMed Central

    Whitmore, Leanne S.; Ye, Ping

    2015-01-01

    Metabolic pathways are increasingly postulated to be vital in programming cell fate, including stemness, differentiation, proliferation, and apoptosis. The commitment to meiosis is a critical fate decision for mammalian germ cells, and requires a metabolic derivative of vitamin A, retinoic acid (RA). Recent evidence showed that a pulse of RA is generated in the testis of male mice thereby triggering meiotic commitment. However, enzymes and reactions that regulate this RA pulse have yet to be identified. We developed a mouse germ cell-specific metabolic network with a curated vitamin A pathway. Using this network, we implemented flux balance analysis throughout the initial wave of spermatogenesis to elucidate important reactions and enzymes for the generation and degradation of RA. Our results indicate that primary RA sources in the germ cell include RA import from the extracellular region, release of RA from binding proteins, and metabolism of retinal to RA. Further, in silico knockouts of genes and reactions in the vitamin A pathway predict that deletion of Lipe, hormone-sensitive lipase, disrupts the RA pulse thereby causing spermatogenic defects. Examination of other metabolic pathways reveals that the citric acid cycle is the most active pathway. In addition, we discover that fatty acid synthesis/oxidation are the primary energy sources in the germ cell. In summary, this study predicts enzymes, reactions, and pathways important for germ cell commitment to meiosis. These findings enhance our understanding of the metabolic control of germ cell differentiation and will help guide future experiments to improve reproductive health. PMID:26367011

  15. Dissecting Germ Cell Metabolism through Network Modeling.

    PubMed

    Whitmore, Leanne S; Ye, Ping

    2015-01-01

    Metabolic pathways are increasingly postulated to be vital in programming cell fate, including stemness, differentiation, proliferation, and apoptosis. The commitment to meiosis is a critical fate decision for mammalian germ cells, and requires a metabolic derivative of vitamin A, retinoic acid (RA). Recent evidence showed that a pulse of RA is generated in the testis of male mice thereby triggering meiotic commitment. However, enzymes and reactions that regulate this RA pulse have yet to be identified. We developed a mouse germ cell-specific metabolic network with a curated vitamin A pathway. Using this network, we implemented flux balance analysis throughout the initial wave of spermatogenesis to elucidate important reactions and enzymes for the generation and degradation of RA. Our results indicate that primary RA sources in the germ cell include RA import from the extracellular region, release of RA from binding proteins, and metabolism of retinal to RA. Further, in silico knockouts of genes and reactions in the vitamin A pathway predict that deletion of Lipe, hormone-sensitive lipase, disrupts the RA pulse thereby causing spermatogenic defects. Examination of other metabolic pathways reveals that the citric acid cycle is the most active pathway. In addition, we discover that fatty acid synthesis/oxidation are the primary energy sources in the germ cell. In summary, this study predicts enzymes, reactions, and pathways important for germ cell commitment to meiosis. These findings enhance our understanding of the metabolic control of germ cell differentiation and will help guide future experiments to improve reproductive health. PMID:26367011

  16. Germ cell specification and ovary structure in the rotifer Brachionus plicatilis

    PubMed Central

    2010-01-01

    Background The segregation of the germline from somatic tissues is an essential process in the development of all animals. Specification of the primordial germ cells (PGCs) takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ('preformation') or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ('epigenesis'). Here we investigate the specification and development of the germ cells in the rotifer Brachionus plicatilis, a member of the poorly-characterized superphyla Lophotrochozoa, by isolating the Brachionus homologues of the conserved germ cell markers vasa and nanos, and examining their expression using in situ hybridization. Results Bpvasa and Bpnos RNA expression have very similar distributions in the Brachionus ovary, showing ubiquitous expression in the vitellarium, with higher levels in the putative germ cell cluster. Bpvas RNA expression is present in freshly laid eggs, remaining ubiquitous in embryos until at least the 96 cell stage after which expression narrows to a small cluster of cells at the putative posterior of the embryo, consistent with the developing ovary. Bpnos RNA expression is also present in just-laid eggs but expression is much reduced by the four-cell stage and absent by the 16-cell stage. Shortly before hatching of the juvenile rotifer from the egg, Bpnos RNA expression is re-activated, located in a subset of posterior cells similar to those expressing Bpvas at the same stage. Conclusions The observed expression of vasa and nanos in the developing B. plicatilis embryo implies an epigenetic origin of primordial germ cells in Rotifer. PMID:20849649

  17. Role of the ABC transporter Mdr49 in Hedgehog signaling and germ cell migration.

    PubMed

    Deshpande, Girish; Manry, Diane; Jourjine, Nicholas; Mogila, Vladic; Mozes, Henny; Bialistoky, Tzofia; Gerlitz, Offer; Schedl, Paul

    2016-06-15

    Coalescence of the embryonic gonad in Drosophila melanogaster requires directed migration of primordial germ cells (PGCs) towards somatic gonadal precursor cells (SGPs). It was recently proposed that the ATP-binding cassette (ABC) transporter Mdr49 functions in the embryonic mesoderm to facilitate the transmission of the PGC attractant from the SGPs; however, the precise molecular identity of the Mdr49-dependent guidance signal remained elusive. Employing the loss- and gain-of-function strategies, we show that Mdr49 is a component of the Hedgehog (hh) pathway and it potentiates the signaling activity. This function is direct because in Mdr49 mutant embryos the Hh ligand is inappropriately sequestered in the hh-expressing cells. Our data also suggest that the role of Mdr49 is to provide cholesterol for the correct processing of the Hh precursor protein. Supporting this conclusion, PGC migration defects in Mdr49 embryos are substantially ameliorated by a cholesterol-rich diet. PMID:27122170

  18. Elucidating human male germ cell development by studying germ cell cancer.

    PubMed

    Nettersheim, Daniel; Jostes, Sina; Schneider, Simon; Schorle, Hubert

    2016-10-01

    Human germ cell development is regulated in a spatio-temporal manner by complex regulatory networks. Here, we summarize results obtained in germ cell tumors and respective cell lines and try to pinpoint similarities to normal germ cell development. This comparison allows speculating about the critical and error-prone mechanisms, which when disturbed, lead to the development of germ cell tumors. Short after specification, primordial germ cells express markers of pluripotency, which, in humans, persists up to the stage of fetal/infantile spermatogonia. Aside from the rare spermatocytic tumors, virtually all seminomas and embryonal carcinomas express markers of pluripotency and show signs of pluripotency or totipotency. Therefore, it appears that proper handling of the pluripotency program appears to be the most critical step in germ cell development in terms of tumor biology. Furthermore, data from mice reveal that germline cells display an epigenetic signature, which is highly similar to pluripotent cells. This signature (poised histone code, DNA hypomethylation) is required for the rapid induction of toti- and pluripotency upon fertilization. We propose that adult spermatogonial cells, when exposed to endocrine disruptors or epigenetic active substances, are prone to reinitiate the pluripotency program, giving rise to a germ cell tumor. The fact that pluripotent cells can be derived from adult murine and human testicular cells further corroborates this idea. PMID:27512122

  19. STELLA Facilitates Differentiation of Germ Cell and Endodermal Lineages of Human Embryonic Stem Cells

    PubMed Central

    Wongtrakoongate, Patompon; Jones, Mark; Gokhale, Paul J.; Andrews, Peter W.

    2013-01-01

    Stella is a developmentally regulated gene highly expressed in mouse embryonic stem (ES) cells and in primordial germ cells (PGCs). In human, the gene encoding the STELLA homologue lies on chromosome 12p, which is frequently amplified in long-term cultured human ES cells. However, the role played by STELLA in human ES cells has not been reported. In the present study, we show that during retinoic acid (RA)-induced differentiation of human ES cells, expression of STELLA follows that of VASA, a marker of germline differentiation. By contrast, human embryonal carcinoma cells express STELLA at a higher level compared with both karyotypically normal and abnormal human ES cell lines. We found that over-expression of STELLA does not interfere with maintenance of the stem cell state of human ES cells, but following retinoic acid induction it leads to up-regulation of germline- and endodermal-associated genes, whereas neural markers PAX6 and NEUROD1 are down-regulated. Further, STELLA over-expression facilitates the differentiation of human ES cells into BE12-positive cells, in which the expression of germline- and endodermal-associated genes is enriched, and suppresses differentiation of the neural lineage. Taken together, this finding suggests a role for STELLA in facilitating germline and endodermal differentiation of human ES cells. PMID:23457636

  20. Germ Cells Need Folate to Proliferate.

    PubMed

    Walker, Amy K

    2016-07-11

    In this issue of Developmental Cell, Chaudhari and colleagues (2016) use a novel method to create an in vitro proliferative cell line from tumorous C. elegans germ cells, and in the process discover that bacterial folates act as signals for proliferation, independent of their roles as vitamins. PMID:27404353

  1. Genomic Landscape of Developing Male Germ Cells

    PubMed Central

    Lee, Tin-Lap; Pang, Alan Lap-Yin; Rennert, Owen M.; Chan, Wai-Yee

    2010-01-01

    Spermatogenesis is a highly orchestrated developmental process by which spermatogonia develop into mature spermatozoa. This process involves many testis- or male germ cell-specific gene products whose expressions are strictly regulated. In the past decade the advent of high-throughput gene expression analytical techniques has made functional genomic studies of this process, particularly in model animals such as mice and rats, feasible and practical. These studies have just begun to reveal the complexity of the genomic landscape of the developing male germ cells. Over 50% of the mouse and rat genome are expressed during testicular development. Among transcripts present in germ cells, 40% – 60% are uncharacterized. A number of genes, and consequently their associated biological pathways, are differentially expressed at different stages of spermatogenesis. Developing male germ cells present a rich repertoire of genetic processes. Tissue-specific as well as spermatogenesis stage-specific alternative splicing of genes exemplifies the complexity of genome expression. In addition to this layer of control, discoveries of abundant presence of antisense transcripts, expressed psuedogenes, non-coding RNAs (ncRNA) including long ncRNAs, microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), and retrogenes all point to the presence of multiple layers of expression and functional regulation in male germ cells. It is anticipated that application of systems biology approaches will further our understanding of the regulatory mechanism of spermatogenesis.† PMID:19306351

  2. Surgery and Combination Chemotherapy in Treating Children With Extracranial Germ Cell Tumors

    ClinicalTrials.gov

    2016-05-06

    Childhood Embryonal Tumor; Childhood Extracranial Germ Cell Tumor; Childhood Extragonadal Germ Cell Tumor; Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Childhood Teratoma; Ovarian Embryonal Carcinoma; Ovarian Yolk Sac Tumor; Stage II Malignant Testicular Germ Cell Tumor; Stage IIA Ovarian Germ Cell Tumor; Stage IIB Ovarian Germ Cell Tumor; Stage IIC Ovarian Germ Cell Tumor; Stage III Malignant Testicular Germ Cell Tumor; Stage IIIA Ovarian Germ Cell Tumor; Stage IIIB Ovarian Germ Cell Tumor; Stage IIIC Ovarian Germ Cell Tumor; Testicular Choriocarcinoma and Yolk Sac Tumor; Testicular Embryonal Carcinoma

  3. Regulation of expression of mouse interferon-induced transmembrane protein like gene-3, Ifitm3 (mil-1, fragilis), in germ cells.

    PubMed

    Tanaka, Satomi S; Nagamatsu, Go; Tokitake, Yuko; Kasa, Miyuki; Tam, Patrick P L; Matsui, Yasuhisa

    2004-08-01

    Mouse interferon-induced transmembrane protein (IFITM) gene, Ifitm3 (previously known as mil-1 and fragilis), is expressed in primordial germ cells (PGCs), in their precursors, and in germ cells of the fetal gonads (Saitou et al. [2002] Nature 418:293-300; Tanaka and Matsui [2002] Mech Dev 119S:S261-S267). By examining the expression of green fluorescent protein transgene under the control of DNA sequences flanking exon 1, we have identified domains that direct Ifitm3 transcription in PGCs and their precursors in gastrula stage and 13.5 days post coitum embryos. Germ cell-specific expression is achieved by the activity of a consensus element unique to the Ifitm genes, which may act to suppress Ifitm3 expression in somatic tissues. The lack of any influence of the interferon-stimulable response elements on transgene expression in the germ-line suggests that interferon-mediated response is not critical for activating Ifitm3. PMID:15254899

  4. Embryonic germ cell lines and their derivation from mouse primordial germ cells.

    PubMed

    Labosky, P A; Barlow, D P; Hogan, B L

    1994-01-01

    When primordial germ cells of the mouse are cultured on feeder layers with the addition of the polypeptide signalling molecules leukaemia inhibitory factor, Steel factor and basic fibroblast growth factor they give rise to cells that resemble undifferentiated blastocyst-derived embryonic stem cells. These primordial germ cell-derived embryonic germ cells (EG cells) can be induced to differentiate extensively in culture and also form teratocarcinomas when injected into nude mice. Additionally, they contribute to chimeras when injected into host blastocysts. We have derived multiple EG cell lines from 8.5 days post coitum (dpc) embryos of C57BL/6 inbred mice. Four independent EG cell lines with normal male karyotypes have formed chimeras (up to 70% coat colour chimerism) when injected into BALB/c host blastocysts. Chimeric mice from all four cell lines are fertile, but only those from one line have transmitted coat colour markers through the germline. Studies have also been carried out to determine whether gonadal primordial germ cells can give rise to pluripotent EG cells. Germ cells from gonads of 15.5 dpc C57BL/6 embryos and newborn mice failed to produce EG cell lines. EG cell lines capable of forming teratocarcinomas and coat colour chimeras have been established from primordial germ cells of 12.5 dpc genital ridges. We are currently testing the genomic imprinting status of the insulin-like growth factor type 2 receptor gene (Igf2r) in our different EG cell lines. PMID:7835148

  5. Dazl is a critical player for primordial germ cell formation in medaka.

    PubMed

    Li, Mingyou; Zhu, Feng; Li, Zhendong; Hong, Ni; Hong, Yunhan

    2016-01-01

    The DAZ family genes boule, daz and dazl have conserved functions in primordial germ cell (PGC) migration, germ stem cell proliferation, differentiation and meiosis progression. It has remained unknown whether this family is required for PGC formation in developing embryos. Our recent study in the fish medaka (Oryzias latipes) has defined dnd as the critical PGC specifier and predicted the presence of additional factors essential for PGC formation. Here we report that dazl is a second key player for medaka PGC formation. Dazl knockdown did not prevent PGC formation even in the absence of normal somatic structures. It turned out that a high level of Dazl protein was maternally supplied and persisted until gastrulation, and hardly affected by two antisense morpholino oligos targeting the dazl RNA translation. Importantly, microinjection of a Dazl antibody remarkably reduced the number of PGCs and even completely abolished PGC formation without causing detectable somatic abnormality. Therefore, medaka PGC formation requires the Dazl protein as maternal germ plasm component, offering first evidence that dazl is a critical player in PGC formation in vivo. Our results demonstrate that antibody neutralization is a powerful tool to study the roles of maternal protein factors in PGC development in vivo. PMID:27328644

  6. Dazl is a critical player for primordial germ cell formation in medaka

    PubMed Central

    Li, Mingyou; Zhu, Feng; Li, Zhendong; Hong, Ni; Hong, Yunhan

    2016-01-01

    The DAZ family genes boule, daz and dazl have conserved functions in primordial germ cell (PGC) migration, germ stem cell proliferation, differentiation and meiosis progression. It has remained unknown whether this family is required for PGC formation in developing embryos. Our recent study in the fish medaka (Oryzias latipes) has defined dnd as the critical PGC specifier and predicted the presence of additional factors essential for PGC formation. Here we report that dazl is a second key player for medaka PGC formation. Dazl knockdown did not prevent PGC formation even in the absence of normal somatic structures. It turned out that a high level of Dazl protein was maternally supplied and persisted until gastrulation, and hardly affected by two antisense morpholino oligos targeting the dazl RNA translation. Importantly, microinjection of a Dazl antibody remarkably reduced the number of PGCs and even completely abolished PGC formation without causing detectable somatic abnormality. Therefore, medaka PGC formation requires the Dazl protein as maternal germ plasm component, offering first evidence that dazl is a critical player in PGC formation in vivo. Our results demonstrate that antibody neutralization is a powerful tool to study the roles of maternal protein factors in PGC development in vivo. PMID:27328644

  7. Human primordial germ cell commitment in vitro associates with a unique PRDM14 expression profile

    PubMed Central

    Sugawa, Fumihiro; Araúzo-Bravo, Marcos J; Yoon, Juyong; Kim, Kee-Pyo; Aramaki, Shinya; Wu, Guangming; Stehling, Martin; Psathaki, Olympia E; Hübner, Karin; Schöler, Hans R

    2015-01-01

    Primordial germ cells (PGCs) develop only into sperm and oocytes in vivo. The molecular mechanisms underlying human PGC specification are poorly understood due to inaccessibility of cell materials and lack of in vitro models for tracking the earliest stages of germ cell development. Here, we describe a defined and stepwise differentiation system for inducing pre-migratory PGC-like cells (PGCLCs) from human pluripotent stem cells (PSCs). In response to cytokines, PSCs differentiate first into a heterogeneous mesoderm-like cell population and then into PGCLCs, which exhibit minimal PRDM14 expression. PGC specification in humans is similar to the murine process, with the sequential activation of mesodermal and PGC genes, and the suppression of neural induction and of de novo DNA methylation, suggesting that human PGC formation is induced via epigenesis, the process of germ cell specification via inductive signals from surrounding somatic cells. This study demonstrates that PGC commitment in humans shares key features with that of the mouse, but also highlights key differences, including transcriptional regulation during the early stage of human PGC development (3–6 weeks). A more comprehensive understanding of human germ cell development may lead to methodology for successfully generating PSC-derived gametes for reproductive medicine. PMID:25750208

  8. Tools for the genetic analysis of germ cells.

    PubMed

    Hammond, Shirley S; Matin, Angabin

    2009-09-01

    Germ cells are essential for the propagation of individual species. Studies on germ cell development in mice highlight important biological paradigms. Beginning with their first appearance around embryonic day 7 (E7), germ cells undergo specific cellular changes at different stages of their embryonic and adult development. Germ cells migrate through the hind-regions of the embryo to eventually home into the developing gonads. Further differentiation and development of germ cells differ in males and females. The processes involved in germ cell development and their eventual differentiation into sperm and oocytes have been under extensive investigation in recent years. Studies on germ cells have shed light on the cellular and molecular processes involved in their specification, migration, proliferation, death, and differentiation. These studies have also revealed much about maintenance of stem cell populations and fertility. Here we review the genetic tools that are at present available to study germ cells in the mouse. PMID:19548313

  9. Identification and Migration of Primordial Germ Cells in Atlantic Salmon, Salmo salar: Characterization of Vasa, Dead End, and Lymphocyte Antigen 75 Genes

    PubMed Central

    Nagasawa, Kazue; Fernandes, Jorge MO; Yoshizaki, Goro; Miwa, Misako; Babiak, Igor

    2013-01-01

    No information exists on the identification of primordial germ cells (PGCs) in the super-order Protacanthopterygii, which includes the Salmonidae family and Atlantic salmon (Salmo salar L.), one of the most commercially important aquatic animals worldwide. In order to identify salmon PGCs, we cloned the full-length cDNA of vasa, dead end (dnd), and lymphocyte antigen 75 (ly75/CD205) genes as germ cell marker candidates, and analyzed their expression patterns in both adult and embryonic stages of Atlantic salmon. Semi-quantitative RT-PCR results showed that salmon vasa and dnd were specifically expressed in testis and ovary, and vasa, dnd, and ly75 mRNA were maternally deposited in the egg. vasa mRNA was consistently detected throughout embryogenesis while dnd and ly75 mRNA were gradually degraded during cleavages. In situ analysis revealed the localization of vasa and dnd mRNA and Ly75 protein in PGCs of hatched larvae. Whole-mount in situ hybridization detected vasa mRNA during embryogenesis, showing a distribution pattern somewhat different to that of zebrafish; specifically, at mid-blastula stage, vasa-expressing cells were randomly distributed at the central part of blastodisc, and then they migrated to the presumptive region of embryonic shield. Therefore, the typical vasa localization pattern of four clusters during blastulation, as found in zebrafish, was not present in Atlantic salmon. In addition, salmon PGCs could be specifically labeled with a green fluorescence protein (GFP) using gfp-rt-vasa 3′-UTR RNA microinjection for further applications. These findings may assist in understanding PGC development not only in Atlantic salmon but also in other salmonids. PMID:23239145

  10. Molecular Characteristics of Malignant Ovarian Germ Cell Tumors and Comparison With Testicular Counterparts: Implications for Pathogenesis

    PubMed Central

    Kraggerud, Sigrid Marie; Hoei-Hansen, Christina E.; Alagaratnam, Sharmini; Skotheim, Rolf I.; Abeler, Vera M.

    2013-01-01

    This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors. PMID:23575763

  11. Molecular characteristics of malignant ovarian germ cell tumors and comparison with testicular counterparts: implications for pathogenesis.

    PubMed

    Kraggerud, Sigrid Marie; Hoei-Hansen, Christina E; Alagaratnam, Sharmini; Skotheim, Rolf I; Abeler, Vera M; Rajpert-De Meyts, Ewa; Lothe, Ragnhild A

    2013-06-01

    This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors. PMID:23575763

  12. General Information about Childhood Extracranial Germ Cell Tumors

    MedlinePlus

    ... Germ Cell Tumors Treatment (PDQ®)–Patient Version General Information About Childhood Extracranial Germ Cell Tumors Go to ... the PDQ Pediatric Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  13. Standard-Dose Combination Chemotherapy or High-Dose Combination Chemotherapy and Stem Cell Transplant in Treating Patients With Relapsed or Refractory Germ Cell Tumors

    ClinicalTrials.gov

    2016-07-26

    Germ Cell Tumor; Teratoma; Choriocarcinoma; Germinoma; Mixed Germ Cell Tumor; Yolk Sac Tumor; Childhood Teratoma; Malignant Germ Cell Neoplasm; Extragonadal Seminoma; Non-seminomatous Germ Cell Tumor; Seminoma

  14. Approaches for identifying germ cell mutagens: Report of the 2013 IWGT workshop on germ cell assays(☆).

    PubMed

    Yauk, Carole L; Aardema, Marilyn J; Benthem, Jan van; Bishop, Jack B; Dearfield, Kerry L; DeMarini, David M; Dubrova, Yuri E; Honma, Masamitsu; Lupski, James R; Marchetti, Francesco; Meistrich, Marvin L; Pacchierotti, Francesca; Stewart, Jane; Waters, Michael D; Douglas, George R

    2015-05-01

    This workshop reviewed the current science to inform and recommend the best evidence-based approaches on the use of germ cell genotoxicity tests. The workshop questions and key outcomes were as follows. (1) Do genotoxicity and mutagenicity assays in somatic cells predict germ cell effects? Limited data suggest that somatic cell tests detect most germ cell mutagens, but there are strong concerns that dictate caution in drawing conclusions. (2) Should germ cell tests be done, and when? If there is evidence that a chemical or its metabolite(s) will not reach target germ cells or gonadal tissue, it is not necessary to conduct germ cell tests, notwithstanding somatic outcomes. However, it was recommended that negative somatic cell mutagens with clear evidence for gonadal exposure and evidence of toxicity in germ cells could be considered for germ cell mutagenicity testing. For somatic mutagens that are known to reach the gonadal compartments and expose germ cells, the chemical could be assumed to be a germ cell mutagen without further testing. Nevertheless, germ cell mutagenicity testing would be needed for quantitative risk assessment. (3) What new assays should be implemented and how? There is an immediate need for research on the application of whole genome sequencing in heritable mutation analysis in humans and animals, and integration of germ cell assays with somatic cell genotoxicity tests. Focus should be on environmental exposures that can cause de novo mutations, particularly newly recognized types of genomic changes. Mutational events, which may occur by exposure of germ cells during embryonic development, should also be investigated. Finally, where there are indications of germ cell toxicity in repeat dose or reproductive toxicology tests, consideration should be given to leveraging those studies to inform of possible germ cell genotoxicity. PMID:25953399

  15. Development of a pheasant interspecies primordial germ cell transfer to chicken embryo: effect of donor cell sex on chimeric semen production.

    PubMed

    Kang, S J; Choi, J W; Park, K J; Lee, Y M; Kim, T M; Sohn, S H; Lim, J M; Han, J Y

    2009-09-01

    This study was conducted to evaluate whether the sex of donor primordial germ cells (PGCs) influences production of chimeric semen from recipient hatchlings produced by interspecies transfer between pheasant (Phasianus colchicus) and chicken (Gallus gallus). Pheasant PGCs were retrieved from 7-d-old embryos and subsequently transferred into circulatory blood of 2.5-d-old (Stage 17) embryos. The sex of embryos was discerned 3 to 6 days after laying, and in preliminary study, overall rate of embryo survival after sexing was 74.6% with male-to-female ratio of 0.49 to 0.51. In Experiment 1, magnetic-activated cell sorting (MACS) using QCR1 antibody was effective for enriching the population of male and female PGCs in gonadal cells (9.2- to 12.5-fold and 10.8- to 19.5-fold increase, respectively). In Experiment 2, an increase in the number of hatchlings producing chimeric semen was detected after the homosexual transfer of male-to-male compared with that after the heterosexual transfer of female-to-male (68% to 88%). Significant increase was found in the frequency of chimeric semen production (0.96 to 1.68 times); production of pheasant progenies by artificial insemination using chimeric semen was also increased in the homosexual transfer (0 to 3 cases). In conclusion, the homosexual PGC transfer of male-to-male yielded better rate of generating pheasant progenies after test cross-reproduction than that of the heterosexual transfer of female-to-male, which could improve the efficiency of interspecies germ cell transfer system. PMID:19515408

  16. Refuting the hypothesis that the acquisition of germ plasm accelerates animal evolution.

    PubMed

    Whittle, Carrie A; Extavour, Cassandra G

    2016-01-01

    Primordial germ cells (PGCs) give rise to the germ line in animals. PGCs are specified during embryogenesis either by an ancestral mechanism of cell-cell signalling (induction) or by a derived mechanism of maternally provided germ plasm (preformation). Recently, a hypothesis was set forth purporting that germ plasm liberates selective constraint and accelerates an organism's protein sequence evolution, especially for genes from early developmental stages, thereby leading to animal species radiations; empirical validation has been claimed in vertebrates. Here we present findings from global rates of protein evolution in vertebrates and invertebrates refuting this hypothesis. Contrary to assertions of the hypothesis, we find no effect of preformation on protein sequence evolution, the evolutionary rates of early-stage developmental genes, or on species diversification. We conclude that the hypothesis is mechanistically implausible, and our multi-faceted analysis shows no empirical support for any of its predictions. PMID:27577604

  17. Conserved elements in the nanos3 3'UTR of olive flounder are responsible for the selective retention of RNA in germ cells.

    PubMed

    Li, Meijie; Tan, Xungang; Sui, Yulei; Jiao, Shuang; Wu, Zhihao; You, Feng

    2016-08-01

    In teleost fish, primordial germ cells (PGCs) are specified very early during embryogenesis and migrate to the site that gonads are formed. A previous study indicated that nanos3 is specifically expressed in PGCs, and the 3' untranslated region (UTR) of nanos3 is responsible for the localization of mRNA in these cells. In this study, we aimed to investigate the functional regions of nanos3 3'UTR in olive flounder using truncated and mutated nanos3 3'UTRs fused to chimeric RNAs and microinjected into fertilized zebrafish eggs. The results indicated that a 68-bp functional element in the nanos3 3'UTR of olive flounder played important roles in the protection and degradation of RNA. Within this element, a U-rich region was identified to be responsible for the protection of RNA in PGCs and two GCAC sites for the degradation of RNA in somatic cells. The first GCAC was located adjacently to the U-rich region and the second GCAC within the U-rich region. Overall, we concluded that the two GCACs were the binding sites of miR-430, a microRNA that suppresses translation, whereas the U-rich region was the binding site of Dnd, a protein that antagonizes the miR-430-mediated silencing of mRNA. PMID:27085583

  18. Production of Functional Gametes from Cryopreserved Primordial Germ Cells of the Japanese Quail

    PubMed Central

    NAKAMURA, Yoshiaki; TASAI, Mariko; TAKEDA, Kumiko; NIRASAWA, Keijiro; TAGAMI, Takahiro

    2013-01-01

    Abstract The Japanese quail (Coturnix japonica) is a valuable bird as both an experimental animal, for a wide range of scientific disciplines, and an agricultural animal, for the production of eggs and meat. Cryopreservation of PGCs would be a feasible strategy for the conservation of both male and female fertility cells in Japanese quail. However, the effects of freeze-thaw treatment on viability, migration ability and germline transmission ability of quail PGCs still remain unclear. In the present study, male and female PGCs were isolated from the blood of 2-day-old embryos, which were cooled by slow freezing and then cryopreserved at –196 C for 77–185 days, respectively. The average recovery rate of PGCs after freeze-thawing was 47.0%. The viability of PGCs in the frozen group was significantly lower than that of the control group (P<0.05) (85.5% vs. 95.1%). Both fresh and Frozen-thawed PGCs that were intravascularly transplanted into recipient embryos migrated toward and were incorporated into recipient gonads, although the number of PGCs settled in the gonads was 48.5% lower in the frozen group than in the unfrozen control group (P<0.05). Genetic cross analysis revealed that one female and two male recipients produced live progeny derived from the frozen-thawed PGCs. The frequency of donor-derived offspring was slightly lower than that of unfrozen controls, but the difference was not significant (4.0 vs. 14.0%). These results revealed that freeze-thaw treatment causes a decrease in viability, migration ability and germline transmission ability of PGCs in quail. PMID:24077020

  19. Quantification of immunocompetent cells in testicular germ cell tumours.

    PubMed

    Torres, A; Casanova, J F; Nistal, M; Regadera, J

    1997-01-01

    The immunocompetent cells present in the different histological patterns of 43 testicular germ cell tumours were evaluated. CD3 + and CD45RO + (UCHL1 +) T lymphocytes, CD68 + and MAC 387 + macrophages, CD20 + (L26 +) B lymphocytes, and kappa and lambda + plasma cells were counted. The number of immunocompetent cells per mm2 of tumour tissue, excluding the necrotic areas, was evaluated. Microscopic fields were randomly selected by two observers. In order to guarantee randomization each surface was divided into parts, numbered through a lattice, and some fields were chosen via a random numbers table. This procedure yielded significantly different counts from those obtained on subjective selection. The number of T-lymphocytes and macrophages was higher in seminomas than in the non-seminomatous testicular germ cell tumours (P < 0.05) Embryonal carcinomas had more T-lymphocytes than immature teratomas. No significant differences were found among testicular germ cell tumours with regards to the B-lymphocytes, with the exception of the high number of B-lymphocytes in mature teratomas. Kappa + and lambda + plasma cells were few in the testicular germ cell tumours. Randomization in the quantification of immunocompetent cells in testicular germ cell tumours is a good means for evaluation of immune response in all the tumour mass, not only in the areas with the most intense inflammatory cell infiltrate, and permits comparison of testicular germ cell tumours with other malignant tumours. Study of immunocompetent cells in every histological type of testicular germ cell tumour is useful in comparing them with other extra-testicular germ cell tumours. PMID:9023554

  20. Dnd knockout ablates germ cells and demonstrates germ cell independent sex differentiation in Atlantic salmon

    PubMed Central

    Wargelius, Anna; Leininger, Sven; Skaftnesmo, Kai Ove; Kleppe, Lene; Andersson, Eva; Taranger, Geir Lasse; Schulz, Rüdiger W; Edvardsen, Rolf B

    2016-01-01

    Introgression of farmed salmon escapees into wild stocks is a major threat to the genetic integrity of wild populations. Using germ cell-free fish in aquaculture may mitigate this problem. Our study investigated whether it is possible to produce germ cell-free salmon in F0 by using CRISPR-Cas9 to knock out dnd, a factor required for germ cell survival in vertebrates. To avoid studying mosaic animals, sgRNA targeting alb was simultaneously used as a visual tracer since the phenotype of alb KO is complete loss of pigmentation. Induced mutations for the tracer (alb) and the target (dnd) genes were highly correlated and produced germ cell-less fish lacking pigmentation, underlining the suitability of alb KO to serve as tracer for targeted double allelic mutations in F0 animals in species with prohibitively long generation times. This is also the first report describing dnd knockout in any fish species. Analyzing gene expression and histology of dnd KO fish revealed that sex differentiation of the somatic compartment does not depend on the presence of germ cells. However, the organization of the ovarian somatic compartment seems compromised in mutant fish. PMID:26888627

  1. Inducible Sterilization of Zebrafish by Disruption of Primordial Germ Cell Migration

    PubMed Central

    Wong, Ten-Tsao; Collodi, Paul

    2013-01-01

    During zebrafish development, a gradient of stromal-derived factor 1a (Sdf1a) provides the directional cue that guides the migration of the primordial germ cells (PGCs) to the gonadal tissue. Here we describe a method to produce large numbers of infertile fish by inducing ubiquitous expression of Sdf1a in zebrafish embryos resulting in disruption of the normal PGC migration pattern. A transgenic line of zebrafish, Tg(hsp70:sdf1a-nanos3, EGFP), was generated that expresses Sdf1a under the control of the heat-shock protein 70 (hsp70) promoter and nanos3 3?UTR. To better visualize the PGCs, the Tg(hsp70:sdf1a-nanos3, EGFP) fish were crossed with another transgenic line, Tg(kop:DsRed-nanos3), that expresses DsRed driven by the PGC-specific kop promoter. Heat treatment of the transgenic embryos caused an induction of Sdf1a expression throughout the embryo resulting in the disruption of their normal migration. Optimal embryo survival and disruption of PGC migration was achieved when transgenic embryos at the 4- to 8-cell stage were incubated at 34.5°C for 18 hours. Under these conditions, disruption of PGC migration was observed in 100% of the embryos. Sixty-four adult fish were developed from three separate batches of heat-treated embryos and all were found to be infertile males. When each male was paired with a wild-type female, only unfertilized eggs were produced and histological examination revealed that each of the adult male fish possessed severely under-developed gonads that lacked gametes. The results demonstrate that inducible Sdf1a expression is an efficient and reliable strategy to produce infertile fish. This approach makes it convenient to generate large numbers of infertile adult fish while also providing the capability to maintain a fertile brood stock. PMID:23826390

  2. Repressive translational control in germ cells.

    PubMed

    Lai, Fangfang; King, Mary Lou

    2013-08-01

    The earliest stages of embryonic development in many animals proceed without zygotic transcription. Genetic control is executed by maternally inherited mRNAs that are under translational control. To set aside the future germ cell lineage, it is pivotal to both exert translational regulation of maternal germline mRNAs and to repress maternal signals in those same cells that drive somatic cell-fate determination. Here we review repressive translational regulation in the germline from the perspective of the conserved RNA binding proteins Pumilio and Nanos, and discuss common themes that have emerged. PMID:23408501

  3. Molecular biology of testicular germ cell tumors.

    PubMed

    Gonzalez-Exposito, R; Merino, M; Aguayo, C

    2016-06-01

    Testicular germ cell tumors (TGCTs) are the most common solid tumors in young adult men. They constitute a unique pathology because of their embryonic and germ origin and their special behavior. Genetic predisposition, environmental factors involved in their development and genetic aberrations have been under study in many works throughout the last years trying to explain the susceptibility and the transformation mechanism of TGCTs. Despite the high rate of cure in this type of tumors because its particular sensitivity to cisplatin, there are tumors resistant to chemotherapy for which it is needed to find new therapies. In the present work, it has been carried out a literature review on the most important molecular aspects involved in the onset and development of such tumors, as well as a review of the major developments regarding prognostic factors, new prognostic biomarkers and the possibility of new targeted therapies. PMID:26482724

  4. Sex Specification and Heterogeneity of Primordial Germ Cells in Mice

    PubMed Central

    Sakashita, Akihiko; Kawabata, Yukiko; Jincho, Yuko; Tajima, Shiun; Kumamoto, Soichiro; Kobayashi, Hisato; Matsui, Yasuhisa; Kono, Tomohiro

    2015-01-01

    In mice, primordial germ cells migrate into the genital ridges by embryonic day 13.5 (E13.5), where they are then subjected to a sex-specific fate with female and male primordial germ cells undergoing mitotic arrest and meiosis, respectively. However, the sex-specific basis of primordial germ cell differentiation is poorly understood. The aim of this study was to investigate the sex-specific features of mouse primordial germ cells. We performed RNA-sequencing (seq) of E13.5 female and male mouse primordial germ cells using next-generation sequencing. We identified 651 and 428 differentially expressed transcripts (>2-fold, P < 0.05) in female and male primordial germ cells, respectively. Of these, many transcription factors were identified. Gene ontology and network analysis revealed differing functions of the identified female- and male-specific genes that were associated with primordial germ cell acquisition of sex-specific properties required for differentiation into germ cells. Furthermore, DNA methylation and ChIP-seq analysis of histone modifications showed that hypomethylated gene promoter regions were bound with H3K4me3 and H3K27me3. Our global transcriptome data showed that in mice, primordial germ cells are decisively assigned to a sex-specific differentiation program by E13.5, which is necessary for the development of vital germ cells. PMID:26700643

  5. On the development of extragonadal and gonadal human germ cells

    PubMed Central

    Heeren, A. Marijne; He, Nannan; de Souza, Aline F.; Goercharn-Ramlal, Angelique; van Iperen, Liesbeth; Roost, Matthias S.; Gomes Fernandes, Maria M.; van der Westerlaken, Lucette A. J.; Chuva de Sousa Lopes, Susana M.

    2016-01-01

    ABSTRACT Human germ cells originate in an extragonadal location and have to migrate to colonize the gonadal primordia at around seven weeks of gestation (W7, or five weeks post conception). Many germ cells are lost along the way and should enter apoptosis, but some escape and can give rise to extragonadal germ cell tumors. Due to the common somatic origin of gonads and adrenal cortex, we investigated whether ectopic germ cells were present in the human adrenals. Germ cells expressing DDX4 and/or POU5F1 were present in male and female human adrenals in the first and second trimester. However, in contrast to what has been described in mice, where ‘adrenal’ and ‘ovarian’ germ cells seem to enter meiosis in synchrony, we were unable to observe meiotic entry in human ‘adrenal’ germ cells until W22. By contrast, ‘ovarian’ germ cells at W22 showed a pronounced asynchronous meiotic entry. Interestingly, we observed that immature POU5F1+ germ cells in both first and second trimester ovaries still expressed the neural crest marker TUBB3, reminiscent of their migratory phase. Our findings highlight species-specific differences in early gametogenesis between mice and humans. We report the presence of a population of ectopic germ cells in the human adrenals during development. PMID:26834021

  6. Combination Chemotherapy in Treating Young Patients With Recurrent or Resistant Malignant Germ Cell Tumors

    ClinicalTrials.gov

    2016-04-12

    Childhood Extracranial Germ Cell Tumor; Childhood Extragonadal Germ Cell Tumor; Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Ovarian Choriocarcinoma; Ovarian Embryonal Carcinoma; Ovarian Yolk Sac Tumor; Recurrent Childhood Malignant Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Testicular Choriocarcinoma; Testicular Choriocarcinoma and Embryonal Carcinoma; Testicular Choriocarcinoma and Yolk Sac Tumor; Testicular Embryonal Carcinoma; Testicular Embryonal Carcinoma and Yolk Sac Tumor; Testicular Yolk Sac Tumor

  7. Human second trimester amniotic fluid cells are able to create embryoid body-like structures in vitro and to show typical expression profiles of embryonic and primordial germ cells.

    PubMed

    Antonucci, Ivana; Di Pietro, Roberta; Alfonsi, Melissa; Centurione, Maria Antonietta; Centurione, Lucia; Sancilio, Silvia; Pelagatti, Francesca; D'Amico, Maria Angela; Di Baldassarre, Angela; Piattelli, Adriano; Tetè, Stefano; Palka, Giandomenico; Borlongan, Cesar V; Stuppia, Liborio

    2014-01-01

    Human amniotic fluid-derived stem cells (AFSCs) represent a novel class of broadly multipotent stem cells sharing characteristics of both embryonic and adult stem cells. However, both the origin of these cells and their actual properties in terms of pluripotent differentiation potential are still debated. In order to verify the presence of features of pluripotency in human second trimester AFSCs, we have investigated the ability of these cells to form in vitro three-dimensional aggregates, known as embryoid bodies (EBs), and to express specific genes of embryonic stem cells (ESCs) and primordial germ cells (PGCs). EBs were obtained after 5 days of AFSC culture in suspension and showed positivity for alkaline phosphatase (AP) staining and for specific markers of pluripotency (OCT4 and SOX2). Moreover, EB-derived cells showed the expression of specific transcripts of the three germ layers. RT-PCR analysis, carried out at different culture times (second, third, fourth, fifth, and eighth passages), revealed the presence of specific markers of ESCs (such as FGF4 and DAPPA4), as well as of markers typical of PGCs and, in particular, genes involved in early stages of germ cell development (Fragilis, Stella, Vasa, c-Kit, Rnf17). Finally, the expression of genes related to the control of DNA methylation (DNMT3A, DNMT3b1, DNMT1, DNMT3L, MBD1, MBD2, MBD3, MDB4, MeCP2), as well as the lack of inactivation of the X-chromosome in female samples, was also demonstrated. Taken together, these data provide further evidence for the presence of common features among human AFSCs, PGCs, and ESCs. PMID:24480362

  8. Molecular characterization and expression pattern of a germ cell marker gene dnd in gibel carp (Carassius gibelio).

    PubMed

    Li, Shi-Zhu; Liu, Wei; Li, Zhi; Wang, Yang; Zhou, Li; Yi, Mei-Sheng; Gui, Jian-Fang

    2016-10-10

    As a germ cell marker gene, Dead end (dnd) has been identified and characterized in many vertebrates. Recently, we created a complete germ cell-depleted gonad model by the dnd-specific morpholino-mediated knockdown approach, and revealed sex-biased gene expression alteration through utilizing unisexual gynogenetic superiority in polyploid gibel carp. However, dnd and its expression pattern are still unclear in the gibel carp. In this study, we further analyzed molecular characterization of gibel carp dnd and its dynamic expression pattern during gametogenesis and embryogenesis. Similar to other homologs in vertebrates, gibel carp dnd contains a conserved RRM motif and five other motifs, and is highly evolutionary conserved in genomic organization and neighborhood gene synteny. RT-PCR and Western blot analyses showed its gonad-specific expression intensively in testis and ovary. Section in situ hybridization (SISH) and immunofluorescence localization revealed its dynamic expression pattern specific to oogenic cells and spermatogenetic cells during oogenesis and spermatogenesis. Moreover, its temporal and spatial distribution specific to PGCs were also demonstrated by RT-PCR and whole mount in situ hybridization (WISH) during embryogenesis. Therefore, gibel carp Dnd is a conserved germ cell marker during gametogenesis, and its maternal transcript is also a useful marker for tracing PGC specification and migration. PMID:27418526

  9. Spindle assembly checkpoint gene mdf-1 regulates germ cell proliferation in response to nutrition signals in C. elegans

    PubMed Central

    Watanabe, Sonoko; Yamamoto, Takaharu G; Kitagawa, Risa

    2008-01-01

    When newly hatched Caenorhabditis elegans larvae are starved, their primordial germ cells (PGCs) arrest in the post-S phase. This starvation-induced PGC arrest is mediated by the DAF-18/PTEN–AKT-1/PKB nutrient-sensing pathway. Here, we report that the conserved spindle assembly checkpoint (SAC) component MDF-1/MAD1 is required for the PGC arrest. We identified 2 Akt kinase phosphorylation sites on MDF-1. Expression of a non-phosphorylatable mutant MDF-1 partially suppressed the defect in the starvation-induced PGC arrest in L1 larvae lacking DAF-18, suggesting that MDF-1 regulates germ cell proliferation as a downstream target of AKT-1, thereby demonstrating a functional link between cell-cycle regulation by the SAC components and nutrient sensing by DAF-18–AKT-1 during post-embryonic development. The phosphorylation status of MDF-1 affects its binding to another SAC component, MDF-2/MAD2. The loss of MDF-2 or another SAC component also caused inappropriate germ cell proliferation, but the defect was less severe than that caused by mdf-1 hemizygosity, suggesting that MDF-1 causes the PGC arrest by two mechanisms, one involving MDF-2 and another that is independent of other SAC components. PMID:18309291

  10. Primary pulmonary germ cell tumor with blastomatous differentiation.

    PubMed

    Miller, R R; Champagne, K; Murray, R C

    1994-11-01

    We describe the clinical and pathologic findings of a patient with mixed blastoma-germ cell malignancy primary in the lung. Serum alpha-fetoprotein levels were elevated at presentation, and normalized with anti-germ cell chemotherapy. The resection specimen contained massively necrotic germ cell tumor with viable mature neural tissue, plus viable biphasic blastoma with stromal bone and skeletal muscle differentiation. It is not clear whether the germ cell component represents unusual differentiation of a somatic cell line or whether the blastoma component represents an unusual pattern of teratomatous differentiation. PMID:7525163

  11. Sexually dimorphic expression of Dmrt1 and γH2AX in germ stem cells during gonadal development in Xenopus laevis.

    PubMed

    Fujitani, Kazuko; Otomo, Asako; Wada, Mikako; Takamatsu, Nobuhiko; Ito, Michihiko

    2016-04-01

    In many animals, primordial germ cells (PGCs) migrate into developing gonads. There, they proliferate and differentiate into female and male germ stem cells (GSCs), oogonia and spermatogonia, respectively. Few studies have focused on the molecular mechanisms underlying the development of GSC sex determination. Here, we investigated the expression of the transcription factor Dmrt1 and a phosphorylated form of the histone variant H2AX (γH2AX) during gonadal development in Xenopus laevis. During early sexual differentiation, Dmrt1 was expressed in the GSCs of the ZW (female) and ZZ (male) gonads as well as somatic cells of the ZZ gonads. Notably, the PGCs and primary GSCs contained large, unstructured nuclei, whereas condensed, rounder nuclei appeared only in primary oogonia during tadpole development. After metamorphosis, Dmrt1 showed its expression in secondary spermatogonia, but not in secondary oogonia. Like Dmrt1, γH2AX was expressed in the nuclei of primary GSCs in early developing gonads. However, after metamorphosis, γH2AX expression continued in primary and secondary spermatogonia, but was barely detected in the condensed nuclei of primary oogonia. Taken together, these observations indicate that spermatogonia tend to retain PGC characteristics, compared to oogonia, which undergo substantial changes during gonadal differentiation in X. laevis. Our findings suggest that Dmrt1 and γH2AX may contribute to the maintenance of stem cell identity by controlling gene expression and epigenetic changes, respectively. PMID:27239441

  12. Primordial Germ Cells: Current Knowledge and Perspectives

    PubMed Central

    Nikolic, Aleksandar; Volarevic, Vladislav; Armstrong, Lyle; Lako, Majlinda; Stojkovic, Miodrag

    2016-01-01

    Infertility is a condition that occurs very frequently and understanding what defines normal fertility is crucial to helping patients. Causes of infertility are numerous and the treatment often does not lead to desired pregnancy especially when there is a lack of functional gametes. In humans, the primordial germ cell (PGC) is the primary undifferentiated stem cell type that will differentiate towards gametes: spermatozoa or oocytes. With the development of stem cell biology and differentiation protocols, PGC can be obtained from pluripotent stem cells providing a new therapeutic possibility to treat infertile couples. Recent studies demonstrated that viable mouse pups could be obtained from in vitro differentiated stem cells suggesting that translation of these results to human is closer. Therefore, the aim of this review is to summarize current knowledge about PGC indicating the perspective of their use in both research and medical application for the treatment of infertility. PMID:26635880

  13. Late Relapse of Testicular Germ Cell Tumors.

    PubMed

    O'Shaughnessy, Matthew J; Feldman, Darren R; Carver, Brett S; Sheinfeld, Joel

    2015-08-01

    Germ cell tumors of the testis have an overall survival rate greater than 90% as a result of a successful multidisciplinary approach to management. Late relapse affects a subset of patients however, and tends to be chemorefractory and the overall prognosis is poor. Surgery is the mainstay in management of late relapse but salvage chemotherapy can be successful. In this review, the clinical presentation and detection of late relapse, clinical outcomes, and predictors of survival in late relapse and the importance of a multidisciplinary treatment approach for successful management of late relapse are discussed. PMID:26216823

  14. RTN3 Regulates the Expression Level of Chemokine Receptor CXCR4 and is Required for Migration of Primordial Germ Cells

    PubMed Central

    Li, Haitao; Liang, Rong; Lu, Yanan; Wang, Mengxia; Li, Zandong

    2016-01-01

    CXCR4 is a crucial chemokine receptor that plays key roles in primordial germ cell (PGC) homing. To further characterize the CXCR4-mediated migration of PGCs, we screened CXCR4-interacting proteins using yeast two-hybrid screening. We identified reticulon3 (RTN3), a member of the reticulon family, and considered an apoptotic signal transducer, as able to interact directly with CXCR4. Furthermore, we discovered that the mRNA and protein expression levels of CXCR4 could be regulated by RTN3. We also found that RTN3 altered CXCR4 translocation and localization. Moreover, increasing the signaling of either CXCR4b or RTN3 produced similar PGC mislocalization phenotypes in zebrafish. These results suggested that RTN3 modulates PGC migration through interaction with, and regulation of, CXCR4. PMID:27070582

  15. Germ line development: lessons learned from pluripotent stem cells.

    PubMed

    Martínez-Arroyo, Ana M; Medrano, Jose V; Remohí, José; Simón, Carlos

    2014-10-01

    Current knowledge about mammalian germ line development is mainly based on the mouse model and little is known about how this fundamental process occurs in humans. This review summarizes our current knowledge of genetic and epigenetic germ line development in mammals, mainly focusing on primordial germ cell (PGC) specification events, comparing the differences between mouse and human models. We also emphasize the knowledge derived from the most successful strategies used to generate germ cell-like cells in vitro in both models and major obstacles to obtaining bona fide in vitro-derived gametes are considered. PMID:25461452

  16. Induction of Germ Cell-like Cells from Porcine Induced Pluripotent Stem Cells.

    PubMed

    Wang, Hanning; Xiang, Jinzhu; Zhang, Wei; Li, Junhong; Wei, Qingqing; Zhong, Liang; Ouyang, Hongsheng; Han, Jianyong

    2016-01-01

    The ability to generate germ cells from pluripotent stem cells (PSCs) is valuable for human regenerative medicine and animal breeding. Germ cell-like cells (GCLCs) have been differentiated from mouse and human PSCs, but not from porcine PSCs, which are considered an ideal model for stem cell applications. Here, we developed a defined culture system for the induction of primordial germ cell-like cells (PGCLCs) from porcine induced PSCs (piPSCs). The identity of the PGCLCs was characterized by observing cell morphology, detecting germ cell marker gene expression and evaluating epigenetic properties. PGCLCs could further differentiate into spermatogonial stem cell-like cells (SSCLCs) in vitro. Importantly, meiosis occurred during SSCLC induction. Xenotransplantation of GCLCs into seminiferous tubules of infertile immunodeficient mice resulted in immunohistochemically identifiable germ cells in vivo. Overall, our study provides a feasible strategy for directing piPSCs to the germ cell fate and lays a foundation for exploring germ cell development mechanisms. PMID:27264660

  17. Induction of Germ Cell-like Cells from Porcine Induced Pluripotent Stem Cells

    PubMed Central

    Wang, Hanning; Xiang, Jinzhu; Zhang, Wei; Li, Junhong; Wei, Qingqing; Zhong, Liang; Ouyang, Hongsheng; Han, Jianyong

    2016-01-01

    The ability to generate germ cells from pluripotent stem cells (PSCs) is valuable for human regenerative medicine and animal breeding. Germ cell-like cells (GCLCs) have been differentiated from mouse and human PSCs, but not from porcine PSCs, which are considered an ideal model for stem cell applications. Here, we developed a defined culture system for the induction of primordial germ cell-like cells (PGCLCs) from porcine induced PSCs (piPSCs). The identity of the PGCLCs was characterized by observing cell morphology, detecting germ cell marker gene expression and evaluating epigenetic properties. PGCLCs could further differentiate into spermatogonial stem cell-like cells (SSCLCs) in vitro. Importantly, meiosis occurred during SSCLC induction. Xenotransplantation of GCLCs into seminiferous tubules of infertile immunodeficient mice resulted in immunohistochemically identifiable germ cells in vivo. Overall, our study provides a feasible strategy for directing piPSCs to the germ cell fate and lays a foundation for exploring germ cell development mechanisms. PMID:27264660

  18. Pediatric germ cell tumors presenting beyond childhood?

    PubMed

    Oosterhuis, J W; Stoop, J A; Rijlaarsdam, M A; Biermann, K; Smit, V T H B M; Hersmus, R; Looijenga, L H J

    2015-01-01

    Four cases are reported meeting the criteria of a pediatric (i.e., Type I) testicular germ cell tumor (TGCT), apart from the age of presentation, which is beyond childhood. The tumors encompass the full spectrum of histologies of pediatric TGCT: teratoma, yolk sac tumor, and various combinations of the two, and lack intratubular germ cell neoplasia/carcinoma in situ in the adjacent parenchyma. The neoplasms are (near)diploid, and lack gain of 12p, typical for seminomas and non-seminomas of the testis of adolescents and adults (i.e., Type II). It is proposed that these neoplasms are therefore late appearing pediatric (Type I) TGCT. The present report broadens the concept of earlier reported benign teratomas of the post-pubertal testis to the full spectrum of pediatric TGCT. The possible wide age range of pediatric TGCT, demonstrated in this study, lends credence to the concept that TGCT should according to their pathogenesis be classified into the previously proposed types. This classification is clinically relevant, because Type I mature teratomas are benign tumors, which are candidates for testis conserving surgery, as opposed to Type II mature teratomas, which have to be treated as Type II (malignant) non-seminomas. PMID:25427839

  19. Molecular genetics of testicular germ cell tumors

    PubMed Central

    Sheikine, Yuri; Genega, Elizabeth; Melamed, Jonathan; Lee, Peng; Reuter, Victor E.; Ye, Huihui

    2012-01-01

    Testicular germ cell tumors (TGCT) are the most common malignancy in young men. While most TGCT are potentially curable, approximately 5% of patients with TGCT may develop chemoresistance and die from the disease. This review article summarizes current knowledge in genetics underlying the development, progression and chemoresistance of TGCT. Most post-pubertal TGCT originate from intratubular germ cell neoplasia unclassified (IGCNU), which are transformed fetal gonocytes. Development of IGCNU may involve aberrantly activated KITLG/KIT pathway and overexpression of embryonic transcription factors such as NANOG and POU5F1, which leads to suppression of apoptosis, increased proliferation, and accumulation of mutations in gonocytes. Invasive TGCT consistently show gain of chromosome 12p, typically isochromosome 12p. Single gene mutations are uncommon in TGCT. KIT, TP53, KRAS/NRAS, and BRAF are genes most commonly mutated in TGCT and implicated in their pathogenesis. Different histologic subtypes of TGCT possess different gene expression profiles that reflect different directions of differentiation. Their distinct gene expression profiles are likely caused by epigenetic regulation, in particular DNA methylation, but not by gene copy number alterations. Resistance of TGCT to chemotherapy has been linked to karyotypic aberrations, single-gene mutations, and epigenetic regulation of gene expression in small-scale studies. The study of TGCT genetics could ultimately translate into development of new molecular diagnostic and therapeutic modalities for these tumors and improve the care of patients with these malignancies. PMID:22432056

  20. Why do primordial germ cells migrate through an embryo and what does it mean for biological evolution?

    PubMed

    Olovnikov, A M

    2013-10-01

    An explanation of the role of primordial germ cell (PGC) migration during embryogenesis is proposed. According to the hypothesis, various PGCs during their migrations through an early embryo are contacting with anlagen of organs and acquiring nonidentical organ specificities. An individual PGC gets such an organ specificity, which corresponds to specificity of the first anlage with which this PGC has the first contact. As a result, the cellular descendants of PGCs (oocytes or spermatocytes) will express nonidentical organ-specific receptors, hence becoming functionally heterogeneous. Therefore, each clone of germ cells becomes capable of recognizing specifically the molecular signals that correspond only to "its" organ of the body. Such signals are produced by the body's organ when it functions in an extreme mode. Signals from the "exercising" organ of the body are delivered to the gonad only via the brain retransmitter, which is composed of neurons grouped as virtual organs of a homunculus. Homunculi are so-called somatotopic maps of the skeletomotor and other parts of the body represented in the brain. Signals, as complexes of regulatory RNAs and proteins, are transported from the "exercising" organ of the body to the corresponding virtual organ of the homunculus where they are processed and then forwarded to the gonad. The organ-specific signal will be selectively recognized by certain gametocytes according to their organ specificity, and then it will initiate the directed epimutation in the gametocyte genome. The nonrandomness of the gene order in chromosomes, that is the synteny and genetic map, is controlled by the so-called creatron that consolidates the soma and germline into a united system, providing the possibility of evolutionary responses of an organism to environmental influences. PMID:24237154

  1. EDITORIAL INTRODUCTION [TO FEMALE GERM CELLS: BIOLOGY AND GENETIC RISK

    EPA Science Inventory

    This is an editorial introduction to the special issue of utation Research, titled, emale Germ Cells: Biology and Genetic isk, which is an attempt to present a collection of papers that emphasize the distinct properties of female germ cells and their characteristic response to mu...

  2. Spermatogonial Nature of the Germ Cell Component of Canine Testicular Mixed Germ Cell-Sex Cord Stromal Tumours.

    PubMed

    Mizukami, S; Murakami, T; Tanaka, T; Machida, N; Nomura, K; Yoshida, T; Shibutani, M

    2016-07-01

    The present study has characterized the germ cell component of canine testicular mixed germ cell-sex cord stromal tumours (MGSCTs) by examining the histological nature and histochemical and immunohistochemical features using gonocytic and spermatogonial cellular markers, c-Kit, placental alkaline phosphatase (PLAP), protein gene product 9.5 (PGP9.5), Sal-like protein 4 (SALL4), and the periodic acid-Schiff (PAS) reaction. Histologically, all 45 examples of MGSCTs were classified as spermatocytic seminomas (SSs) and Sertoli cell tumours in combination. The germ cell component of all MGSCTs was negative by PAS staining. Immunohistochemically, PLAP immunoreactivity was lacking in the germ cell component of all MGSCTs, which is not consistent with a gonocytic origin. The germ cell component was positive for PGP9.5 and SALL4 in all MGSCTs and positive for c-Kit in 53% of MGSCTs, which is consistent with the phenotype of spermatogonia. Furthermore, the germ cell component in 71% of MGSCTs had moderate immunoreactivity for SALL4, which is suggestive of a spermatogonial phenotype. Conversely, 29% of cases had a minor population of germ cells showing strong SALL4 immunoreactivity, suggesting a phenotype similar to prespermatogonia. The results suggest that the germ cell component of canine MGSCTs is morphologically classified as SS, with the majority of cases showing the spermatogonial phenotype and some cases containing a small population of prespermatogonia. PMID:27241073

  3. The biology of the germ line in echinoderms.

    PubMed

    Wessel, Gary M; Brayboy, Lynae; Fresques, Tara; Gustafson, Eric A; Oulhen, Nathalie; Ramos, Isabela; Reich, Adrian; Swartz, S Zachary; Yajima, Mamiko; Zazueta, Vanessa

    2014-08-01

    The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ-line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed. PMID:23900765

  4. The Biology of the Germ line in Echinoderms

    PubMed Central

    Wessel, Gary M.; Brayboy, Lynae; Fresques, Tara; Gustafson, Eric A.; Oulhen, Nathalie; Ramos, Isabela; Reich, Adrian; Swartz, S. Zachary; Yajima, Mamiko; Zazueta, Vanessa

    2014-01-01

    SUMMARY The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed. PMID:23900765

  5. [Updated genomics of testicular germ cell tumor].

    PubMed

    Zhang, Meng; He, An-bang; Cai, Zhi-ming; Wu, Song

    2015-04-01

    Testicular germ cell tumor (TGCT) is a most common testicular malignancy with an increasing incidence, and its pathogenesis and mechanisms are not yet clear. The next generation sequencing has become the main tool to uncover the underlying mechanisms of TGCT. The differential gene expressions, gene mutation, predisposing gene-dominated signaling pathways, and changes of the relevant genes in the sex chromosome are largely involved in the occurrence and development of TGCT. Studies on the genomics of TGCT contribute a lot to identifying the pivotal pathogenic genes and paving a theoretical ground for the early screening and targeted therapy of TGCT. This paper summarizes the advances in the studies of the genomics of TGCT so as to reveal thetmechanisms of the disease at the genetic level. PMID:26027106

  6. Germ tube-specific antigens of Candida albicans cell walls

    SciTech Connect

    Sundstrom, P.R.

    1986-01-01

    Studies were performed to characterize the surface differences between blastospores and germ tubes of the pathogenic, dimorphic yeast, Candida albicans, and to identify components of yeast cells responsible for these differences. Investigation of surfaces differences of the two growth forms was facilitated by the production of rabbit antiserum prepared against Formalin-treated yeast possessing germ tubes. To prepare antiserum specific for germ tubes, this serum was adsorbed with stationary phase blastospores. Whereas the unadsorbed antiserum reacted with both blastospore and germ tube forms by immunofluorescence and Enzyme-Linked Immunosorbent Assay, the adsorbed antiserum did not react with blastospores but detected germ tube-specific antigens in hyphal forms. The differences between blastospores and germ tubes of Candida albicans, were further studied by comparing enzymatic digests of cell walls of both growth forms in radiolabeled organisms. Organisms were labeled either on the surface with /sup 125/I, or metabolically with (/sup 35/S) methionine or (/sup 3/H) mannose. Three-surface-located components (as shown by antibody adsorption and elution experiments) were precipitated from Zymolase digests. All three components were mannoproteins as shown by their ability to bind Concanavalin A, and to be labeled in protein labeling procedures, and two of these (200,000 and 155,000 molecular weight) were germ tube specific, as shown by their ability to be precipitated by germ tube-specific antiserum. Monoclonal antibodies were prepared to C. albicans, using blastospores bearing germ tubes as immunogen.

  7. NANOG alone induces germ cells in primed epiblast in vitro by activation of enhancers.

    PubMed

    Murakami, Kazuhiro; Günesdogan, Ufuk; Zylicz, Jan J; Tang, Walfred W C; Sengupta, Roopsha; Kobayashi, Toshihiro; Kim, Shinseog; Butler, Richard; Dietmann, Sabine; Surani, M Azim

    2016-01-21

    Nanog, a core pluripotency factor in the inner cell mass of blastocysts, is also expressed in unipotent primordial germ cells (PGCs) in mice, where its precise role is yet unclear. We investigated this in an in vitro model, in which naive pluripotent embryonic stem (ES) cells cultured in basic fibroblast growth factor (bFGF) and activin A develop as epiblast-like cells (EpiLCs) and gain competence for a PGC-like fate. Consequently, bone morphogenetic protein 4 (BMP4), or ectopic expression of key germline transcription factors Prdm1, Prdm14 and Tfap2c, directly induce PGC-like cells (PGCLCs) in EpiLCs, but not in ES cells. Here we report an unexpected discovery that Nanog alone can induce PGCLCs in EpiLCs, independently of BMP4. We propose that after the dissolution of the naive ES-cell pluripotency network during establishment of EpiLCs, the epigenome is reset for cell fate determination. Indeed, we found genome-wide changes in NANOG-binding patterns between ES cells and EpiLCs, indicating epigenetic resetting of regulatory elements. Accordingly, we show that NANOG can bind and activate enhancers of Prdm1 and Prdm14 in EpiLCs in vitro; BLIMP1 (encoded by Prdm1) then directly induces Tfap2c. Furthermore, while SOX2 and NANOG promote the pluripotent state in ES cells, they show contrasting roles in EpiLCs, as Sox2 specifically represses PGCLC induction by Nanog. This study demonstrates a broadly applicable mechanistic principle for how cells acquire competence for cell fate determination, resulting in the context-dependent roles of key transcription factors during development. PMID:26751055

  8. Alvocidib and Oxaliplatin With or Without Fluorouracil and Leucovorin Calcium in Treating Patients With Relapsed or Refractory Germ Cell Tumors

    ClinicalTrials.gov

    2015-05-11

    Recurrent Extragonadal Seminoma; Recurrent Malignant Extragonadal Germ Cell Tumor; Recurrent Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage III Testicular Cancer; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

  9. SALL4 expression in germ cell and non-germ cell tumors: a systematic immunohistochemical study of 3215 cases.

    PubMed

    Miettinen, Markku; Wang, Zengfeng; McCue, Peter A; Sarlomo-Rikala, Maarit; Rys, Janusz; Biernat, Wojciech; Lasota, Jerzy; Lee, Yi-Shan

    2014-03-01

    The SALL4 transcription factor is associated with embryonic cell pluripotency and has been shown as a useful immunohistochemical marker for germ cell tumors. However, information of SALL4 distribution in normal human tissues and non-germ cell tumors is limited. In this study we examined normal human tissues and 3215 tumors for SALL4 expression using a monoclonal antibody 6E3 and automated immunohistochemistry. In a 10-week embryo, SALL4 was expressed in ovocytes, intestine, kidney, and some hepatocytes. In adult tissues, it was only detected in germ cells. SALL4 was consistently expressed in all germ cell tumors except some trophoblastic tumors and mature components of teratomas, in which it was selectively expressed in intestinal-like and some squamous epithelia. In non-germ cell carcinomas, SALL4 was detected in 20% of cases or more of serous carcinoma of the ovary, urothelial high-grade carcinoma, and gastric adenocarcinoma (especially the intestinal type). SALL4 was only rarely (≤ 5%) expressed in mammary, colorectal, prostatic, and squamous cell carcinomas. Many SALL4-positive carcinomas showed poorly differentiated patterns, and some showed positivity in most tumor cells mimicking the expression in germ cell tumors. SALL4 was commonly expressed in rhabdoid tumors of the kidney and extrarenal sites and in the Wilms tumor. Expression of SALL4 was rare in other mesenchymal and neuroendocrine tumors but was occasionally detected in melanoma, desmoplastic small round cell tumor, epithelioid sarcoma, and rhabdomyosarcoma. All hematopoietic tumors were negative. SALL4 is an excellent marker of nonteratomatous germ cell tumors, but it is also expressed in other tumors, sometimes extensively. Such expression may reflect stem cell-like differentiation and must be considered when using SALL4 as a marker for germ cell tumors. Observed lack of other pluripotency factors, OCT4 and NANOG, in SALL4-positive non-germ cell tumors can also be diagnostically helpful. PMID

  10. Development of malignant germ cells - the genvironmental hypothesis.

    PubMed

    Looijenga, Leendert H J; Van Agthoven, Ton; Biermann, Katharina

    2013-01-01

    Human germ cell tumors are of interest because of their epidemiology, clinic and patho-biology. Histologically, they are subdivided into various elements, with similarities to embryogenesis. Recent insight triggered development of a higher order division into five types of human germ cell tumors. In the context of male germ cells, only three are relevant; Type I: teratomas and yolk sac tumors of neonates and infants; Type II: seminomas and nonseminomas of (predominantly) adolescents and adults; and Type III: spermatocytic seminomas of the elderly. Various animal models, both occurring spontaneous or induced, are reported, of which their relevance is still a matter of debate. Recent multidisciplinary studies have led to a significant increase in our understanding of the parameters involved in the earliest pathogenetic steps of human germ cells tumors, particularly the seminomas and nonseminomas (Type II). This paper will discuss a number of interesting insights into the normal and aberrant regulation of germ cell development, resulting in the so-called genvironmental hypothesis. This assumes a subtle interaction between environmental- and (epi)genetic parameters, resulting in clinical/phenotypical characteristics. These influence signaling pathways and thereby developmental processes, including gonadal development, germ cell proliferation, maturation and apoptosis. In the case of a disturbed physiology, either due to the germ cell itself, or the micro-environment, embryonic germ cells, during a specific window of sensitization, might be blocked in their maturation, resulting in carcinoma in situ or gonadoblastoma, the precursors of seminomas and nonseminomas. The level of testicularization of the gonad determines the histological composition of the precursor. These insights will allow a better definition of individuals at risk of developing a germ cell malignancy, and allow a better selection of scientific approaches to elucidate the corresponding pathogenesis. PMID

  11. The testicular germ cell tumour transcriptome.

    PubMed

    Alagaratnam, S; Lind, G E; Kraggerud, S M; Lothe, R A; Skotheim, R I

    2011-08-01

    Testicular germ cell tumours (TGCTs) are characterized by young age of onset and a complex pattern of histological subtypes. Transcriptomic studies have tried to uncover the gene expression patterns underlying this. Here, we present a systematic review of transcriptome studies of TGCTs of adolescents and young adults and identify genes common across the various studies, both for TGCTs in general as well as the histological subtypes, hence elucidating both transcriptional changes associated with malignant transformation and differentiation patterns. A meta-analysis of this type adds power and significance to the genes thus found, where most studies have included only a limited number of samples. Both known (KRAS, MYCN and TPD52) and novel (CCT6A, IGFBP3 and SALL2) cancer genes are implicated in TGC tumorigenesis. Gene expression patterns characteristic to embryonic stem cells are also found deregulated in TGC tumorigenesis. This is reflected in how pluripotent embryonal carcinoma cells commonly differentiate into a variety of embryonic and extra-embryonic histological types, each with unique transcriptomes. The embryonal carcinomas in particular are found to overexpress pluripotency genes, while gene signatures for seminomas, teratomas and yolk sac tumours were also identified. This underlines the distinctive transcriptomic programme across histological subtypes, especially striking given that the TGCT genome is largely similar across the same subtypes. PMID:21651573

  12. Tritium effects on germ cells and fertility

    SciTech Connect

    Dobson, R.L.; Kwan, T.C.; Straume, T.

    1982-11-19

    Primordial oocytes in juvenile mice show acute gamma-ray LD/sub 50/ as low as 6 rad. This provides opportunities for determining dose-response relations at low doses and chronic exposure in the intact animal - conditions of particular interest for hazard evaluation. Examined in this way, /sup 3/HOH in body water is found to kill murine oocytes exponentially with dose, the LD/sub 50/ level for chronic exposure being only 2..mu..Ci/ml (delivering 0.4 rad/day). At very low doses and dose rates, where comparisons between tritium and other radiations are of special significance for radiological protection, the RBE of tritium compared with /sup 60/Co gamma radiation reaches approximately 3. Effects on murine fertility from tritium-induced oocyte loss have been quantified by reproductive capacity measurements. Chronic low-level exposure has been examined also in three primate species - squirrel, rhesus, and bonnet monkeys. In squirrel monkeys the ovarian germ-cell supply is 99% destroyed by the time of birth from prenatal exposure to body-water levels of /sup 3/HOH (administered in maternal drinking water) of only 3 ..mu..Ci/ml, the LD/sub 50/ level being 0.5 ..mu..Ci/ml (giving 0.1 rad/day), one fourth that in mice. Though not completely ruled out, similar high sensitivity of female germ cells has not been found in macaques; and it probably does not occur in man. The exquisite radiosensitivity of primordial oocytes in mice is apparently due to vulnerability of the plasma membrane (or something of similar geometry and location), not DNA. Evidence for this comes from tritium data as well as neutron studies. Tritium administered as /sup 3/HOH, and therefore generally distributed, is much more effective in killing murine oocytes than is tritium administered as /sup 3/H-TdR, localized in the nucleus. This situation in the mouse may have implications for estimating radiation genetic risk in the human female.

  13. Evidence against a germ plasm in the milkweed bug Oncopeltus fasciatus, a hemimetabolous insect

    PubMed Central

    Ewen-Campen, Ben; Jones, Tamsin E. M.; Extavour, Cassandra G.

    2013-01-01

    Summary Primordial germ cell (PGC) formation in holometabolous insects like Drosophila melanogaster relies on maternally synthesised germ cell determinants that are asymmetrically localised to the oocyte posterior cortex. Embryonic nuclei that inherit this “germ plasm” acquire PGC fate. In contrast, historical studies of basally branching insects (Hemimetabola) suggest that a maternal requirement for germ line genes in PGC specification may be a derived character confined principally to Holometabola. However, there have been remarkably few investigations of germ line gene expression and function in hemimetabolous insects. Here we characterise PGC formation in the milkweed bug Oncopeltus fasciatus, a member of the sister group to Holometabola, thus providing an important evolutionary comparison to members of this clade. We examine the transcript distribution of orthologues of 19 Drosophila germ cell and/or germ plasm marker genes, and show that none of them localise asymmetrically within Oncopeltus oocytes or early embryos. Using multiple molecular and cytological criteria, we provide evidence that PGCs form after cellularisation at the site of gastrulation. Functional studies of vasa and tudor reveal that these genes are not required for germ cell formation, but that vasa is required in adult males for spermatogenesis. Taken together, our results provide evidence that Oncopeltus germ cells may form in the absence of germ plasm, consistent with the hypothesis that germ plasm is a derived strategy of germ cell specification in insects. PMID:23789106

  14. Evidence against a germ plasm in the milkweed bug Oncopeltus fasciatus, a hemimetabolous insect.

    PubMed

    Ewen-Campen, Ben; Jones, Tamsin E M; Extavour, Cassandra G

    2013-06-15

    Primordial germ cell (PGC) formation in holometabolous insects like Drosophila melanogaster relies on maternally synthesised germ cell determinants that are asymmetrically localised to the oocyte posterior cortex. Embryonic nuclei that inherit this "germ plasm" acquire PGC fate. In contrast, historical studies of basally branching insects (Hemimetabola) suggest that a maternal requirement for germ line genes in PGC specification may be a derived character confined principally to Holometabola. However, there have been remarkably few investigations of germ line gene expression and function in hemimetabolous insects. Here we characterise PGC formation in the milkweed bug Oncopeltus fasciatus, a member of the sister group to Holometabola, thus providing an important evolutionary comparison to members of this clade. We examine the transcript distribution of orthologues of 19 Drosophila germ cell and/or germ plasm marker genes, and show that none of them localise asymmetrically within Oncopeltus oocytes or early embryos. Using multiple molecular and cytological criteria, we provide evidence that PGCs form after cellularisation at the site of gastrulation. Functional studies of vasa and tudor reveal that these genes are not required for germ cell formation, but that vasa is required in adult males for spermatogenesis. Taken together, our results provide evidence that Oncopeltus germ cells may form in the absence of germ plasm, consistent with the hypothesis that germ plasm is a derived strategy of germ cell specification in insects. PMID:23789106

  15. General Information About Childhood Central Nervous System Germ Cell Tumors

    MedlinePlus

    ... before the cancer is diagnosed and continue for months or years. Childhood CNS germ cell tumors may ... after treatment. Some cancer treatments cause side effects months or years after treatment has ended. Some cancer ...

  16. Activity of nintedanib in germ cell tumors.

    PubMed

    Steinemann, Gustav; Jacobsen, Christine; Gerwing, Mirjam; Hauschild, Jessica; von Amsberg, Gunhild; Höpfner, Michael; Nitzsche, Bianca; Honecker, Friedemann

    2016-02-01

    Germ cell tumors (GCTs) are the most frequent malignancy in male patients between 15 and 45 years of age. Cisplatin-based chemotherapy shows excellent cure rates, but patients with cisplatin-resistant GCTs have a poor prognosis. Nintedanib (BIBF 1120, Vargatef) inhibits the receptor classes vascular endothelial growth factor receptor, platelet derived growth factor receptor, and fibroblast growth factor receptor, and has shown activity against many tumors, as well as in idiopathic lung fibrosis and bleomycin-induced lung injury. Here, we investigated the antineoplastic and antiangiogenic properties of nintedanib in cisplatin-resistant and cisplatin-sensitive GCT cells, both alone and in combination with classical cytotoxic agents such as cisplatin, etoposide, and bleomycin. The half-maximal inhibitory concentration (IC50) of nintedanib was 4.5 ± 0.43 μmol/l, 3.1 ± 0.45 μmol/l, and 3.6 ± 0.33 μmol/l in cisplatin-sensitive NTERA2, 2102Ep, and NCCIT cells, whereas the IC50 doses of the cisplatin-resistant counterparts were 6.6 ± 0.37 μmol/l (NTERA2-R), 4.5 ± 0.83 μmol/l (2102Ep-R), and 6.1 ± 0.41 μmol/l (NCCIT-R), respectively. Single treatment with nintedanib induced apoptosis and resulted in a sustained reduction in the capacity of colony formation in both cisplatin-sensitive and cisplatin-resistant GCT cells. Cell cycle analysis showed that nintedanib induced a strong G0/G1-phase arrest in all investigated cell lines. Combination treatment with cisplatin did not result in additive, synergistic, or antagonistic effects. The in-vivo activity was studied using the chorioallantoic membrane assay and indicated the antiangiogenic potency of nintedanib with markedly reduced microvessel density. Topical treatment of inoculated tumor plaques resulted in a significant reduction of the tumor size. This indicates that nintedanib might be a promising substance in the treatment of GCT. PMID:26479145

  17. The chemosensitivity of testicular germ cell tumors.

    PubMed

    Voutsadakis, Ioannis A

    2014-04-01

    Although rare cancers overall, testicular germ cell tumors (TGCTs) are the most common type of cancer in young males below 40 years of age. Both subtypes of TGCTs, i.e., seminomas and non-seminomas, are highly curable and the majority of even metastatic patients may expect to be cured. These high cure rates are not due to the indolent nature of these cancers, but rather to their sensitivity to chemotherapy (and for seminomas to radiotherapy). The delineation of the cause of chemosensitivity at the molecular level is of paramount importance, because it may provide insights into the minority of TGCTs that are chemo-resistant and, thereby, provide opportunities for specific therapeutic interventions aimed at reverting them to chemosensitivity. In addition, delineation of the molecular basis of TGCT chemo-sensitivity may be informative for the cause of chemo-resistance of other more common types of cancer and, thus, may create new therapeutic leads. p53, a frequently mutated tumor suppressor in cancers in general, is not mutated in TGCTs, a fact that has implications for their chemo-sensitivity. Oct4, an embryonic transcription factor, is uniformly expressed in the seminoma and embryonic carcinoma components of non-seminomas, and its interplay with p53 may be important in the chemotherapy response of these tumors. This interplay, together with other features of TGCTs such as the gain of genetic material from the short arm of chromosome 12 and the association with disorders of testicular development, will be discussed in this paper and integrated in a unifying hypothesis that may explain their chemo-sensitivity. PMID:24692098

  18. Marijuana use and testicular germ cell tumors

    PubMed Central

    Trabert, Britton; Sigurdson, Alice J.; Sweeney, Anne M.; Strom, Sara S.; McGlynn, Katherine A.

    2010-01-01

    Background Since the early 1970's the incidence of testicular germ cell tumors (TGCT) in the U.S. has been increasing, however, potential environmental exposures accounting for this rise have not been identified. A prior study reported a significant association among frequent and long-term current users of marijuana and TGCT risk. We aimed to evaluate the relationship of marijuana use and TGCT in a hospital-based case-control study conducted at The University of Texas M. D. Anderson Cancer Center. Methods TGCT cases diagnosed between January 1990 and October 1996 (n=187) and male friend controls (n=148) were enrolled in the study. All participants were between the ages of 18 and 50 at the time of cases' diagnosis and resided in Texas, Louisiana, Arkansas, or Oklahoma. Associations of marijuana use and TGCT were estimated using unconditional logistic regression, adjusting for age, race, prior cryptorchidism, cigarette smoking and alcohol intake. Results Overall, TGCT cases were more likely to be frequent marijuana users (daily or greater) than were controls [OR: 2.2, 95% CI: 1.0, 5.1]. In the histologic-specific analyses nonseminoma cases were significantly more likely than controls to be frequent users [OR: 3.1, 95% CI: 1.2, 8.2] and long-term users (10+ years) [OR: 2.4, 95% CI: 1.0, 6.1]. Discussion Our finding of an association between frequent marijuana use and TGCT, particularly among men with nonseminoma, is consistent with the findings of a previous report. Additional studies of marijuana use and TGCT are warranted, especially studies evaluating the role of endocannabinoid signaling and cannabinoid receptors in TGCT. PMID:20925043

  19. Mechanisms and chemical induction of aneuploidy in rodent germ cells

    SciTech Connect

    Mailhes, J B; Marchetti, F

    2004-10-15

    The objective of this review is to suggest that the advances being made in our understanding of the molecular events surrounding chromosome segregation in non-mammalian and somatic cell models be considered when designing experiments for studying aneuploidy in mammalian germ cells. Accurate chromosome segregation requires the temporal control and unique interactions among a vast array of proteins and cellular organelles. Abnormal function and temporal disarray among these, and others to be inidentified, biochemical reactions and cellular organelles have the potential for predisposing cells to aneuploidy. Although numerous studies have demonstrated that certain chemicals (mainly those that alter microtubule function) can induce aneuploidy in mammalian germ cells, it seems relevant to point out that such data can be influenced by gender, meiotic stage, and time of cell-fixation post-treatment. Additionally, a consensus has not been reached regarding which of several germ cell aneuploidy assays most accurately reflects the human condition. More recent studies have shown that certain kinase, phosphatase, proteasome, and topoisomerase inhibitors can also induce aneuploidy in rodent germ cells. We suggest that molecular approaches be prudently incorporated into mammalian germ cell aneuploidy research in order to eventually understand the causes and mechanisms of human aneuploidy. Such an enormous undertaking would benefit from collaboration among scientists representing several disciplines.

  20. In Vitro Ectopic Behavior of Porcine Spermatogonial Germ Cells and Testicular Somatic Cells.

    PubMed

    Lee, Kyung Hoon; Lee, Won Young; Do, Jung Tae; Park, Chan Kyu; Kim, Nam Hyung; Kim, Jin Hoi; Chung, Hak Jae; Kim, Dong Woon; Song, Hyuk

    2016-08-01

    Embryonic body-like colony formation is a unique pattern in male germ cell cultures, including spermatogonial stem cells. However, detailed information of the colony formation has not yet been sufficiently reported in male germ cell culture. To elucidate the formation of germ cell-derived colony (GDC), glial cell-derived neurotrophic factor receptor alpha-1 (GFRα-1)-positive pig germ cells were isolated using an immunomagnetic cell isolation method and labeled with red- or green-fluorescent dye. In GDC culture, red-fluorescent-labeled germ cells were evenly distributed in the wells from day 1 to 4, and they clustered together at the time of GDC formation on day 6. Interestingly, feeder cells migrated to the site of colony formation as spermatogonia carriers. Furthermore, when freshly prepared green-labeled GFRα-1-positive germ cells were added, mixed-fluorescent dye (red and green) colonies were observed. On bromodeoxyuridine (BrdU) treatment, 58% ± 3.13% of germ cells were positive to protein gene product 9.5 but negative to BrdU cells. Immunocytochemistry and reverse transcription-polymerase chain reaction results showed that cultured GDC cells were positive to stem cell- and pig germ cell-specific marker genes. In conclusion, in vitro formation of GDCs is mainly dependent on the aggregation of single germ cells as well as on the slow proliferation of germ cells. PMID:27328332

  1. Germ Cell Nuclear Factor Regulates Gametogenesis in Developing Gonads

    PubMed Central

    Sabour, Davood; Xu, Xueping; Chung, Arthur C. K.; Le Menuet, Damien; Ko, Kinarm; Tapia, Natalia; Araúzo-Bravo, Marcos J.; Gentile, Luca; Greber, Boris; Hübner, Karin; Sebastiano, Vittorio; Wu, Guangming; Schöler, Hans R.; Cooney, Austin J.

    2014-01-01

    Expression of germ cell nuclear factor (GCNF; Nr6a1), an orphan member of the nuclear receptor gene family of transcription factors, during gastrulation and neurulation is critical for normal embryogenesis in mice. Gcnf represses the expression of the POU-domain transcription factor Oct4 (Pou5f1) during mouse post-implantation development. Although Gcnf expression is not critical for the embryonic segregation of the germ cell lineage, we found that sexually dimorphic expression of Gcnf in germ cells correlates with the expression of pluripotency-associated genes, such as Oct4, Sox2, and Nanog, as well as the early meiotic marker gene Stra8. To elucidate the role of Gcnf during mouse germ cell differentiation, we generated an ex vivo Gcnf-knockdown model in combination with a regulated CreLox mutation of Gcnf. Lack of Gcnf impairs normal spermatogenesis and oogenesis in vivo, as well as the derivation of germ cells from embryonic stem cells (ESCs) in vitro. Inactivation of the Gcnf gene in vivo leads to loss of repression of Oct4 expression in both male and female gonads. PMID:25140725

  2. Vanadium induced ultrastructural changes and apoptosis in male germ cells.

    PubMed

    Aragón, M A; Ayala, M E; Fortoul, T I; Bizarro, P; Altamirano-Lozano, M

    2005-01-01

    Vanadium is a transition metal that is emitted to the atmosphere during combustion of fossil fuels. In the environment, vanadium occurs in the (V) oxidized form, but in the body it is found exclusively in the (IV) oxidized form. Vanadium tetraoxide is an inorganic chemical species in the (IV) oxidized form that has been shown to induce toxic effects in vitro and in vivo. The reproductive toxicity of vanadium in males was studied through monitoring germ cell apoptosis during spermatogenesis. We analyzed ultrastructural damage, and testosterone and progesterone concentrations following vanadium tetraoxide administered to male mice for 60 days. Spermatogenesis stages I-III and X-XII frequently showed apoptotic germ cells in control and treated animals; vanadium tetraoxide treatment induced an increase in the number of germ cell apoptosis in stages I-III and XII at 9.4 and 18.8 mg/kg, respectively. Although spermatogenesis is regulated by testosterone, in our study this hormone level was not modified by vanadium administration; thus, germ cell death was not related with testosterone concentration. At the ultrastructural level, we observed inclusion structures that varied as to location and content in the Sertoli and germ cells. PMID:15808796

  3. Signaling from germ cells mediated by the rhomboid homolog stet organizes encapsulation by somatic support cells.

    PubMed

    Schulz, Cordula; Wood, Cricket G; Jones, D Leanne; Tazuke, Salli I; Fuller, Margaret T

    2002-10-01

    Germ cells normally differentiate in the context of encapsulating somatic cells. However, the mechanisms that set up the special relationship between germ cells and somatic support cells and the signals that mediate the crucial communications between the two cell types are poorly understood. We show that interactions between germ cells and somatic support cells in Drosophila depend on wild-type function of the stet gene. In males, stet acts in germ cells to allow their encapsulation by somatic cyst cells and is required for germ cell differentiation. In females, stet function allows inner sheath cells to enclose early germ cells correctly at the tip of the germarium. stet encodes a homolog of rhomboid, a component of the epidermal growth factor receptor signaling pathway involved in ligand activation in the signaling cell. The stet mutant phenotype suggests that stet facilitates signaling from germ cells to the epidermal growth factor receptor on somatic cells, resulting in the encapsulation of germ cells by somatic support cells. The micro-environment provided by the surrounding somatic cells may, in turn, regulate differentiation of the germ cells they enclose. PMID:12223409

  4. Crucial Genes and Pathways in Chicken Germ Stem Cell Differentiation

    PubMed Central

    Zhang, Zhentao; Elsayed, Ahmed Kamel; Shi, Qingqing; Zhang, Yani; Zuo, Qisheng; Li, Dong; Lian, Chao; Tang, Beibei; Xiao, Tianrong; Xu, Qi; Chang, Guobin; Chen, Guohong; Zhang, Lei; Wang, Kehua; Wang, Yingjie; Jin, Kai; Wang, Yilin; Song, Jiuzhou; Cui, Hengmi; Li, Bichun

    2015-01-01

    Male germ cell differentiation is a subtle and complex regulatory process. Currently, its regulatory mechanism is still not fully understood. In our experiment, we performed the first comprehensive genome and transcriptome-wide analyses of the crucial genes and signaling pathways in three kinds of crucial cells (embryonic stem cells, primordial germ cell, and spermatogonial stem cells) that are associated with the male germ cell differentiation. We identified thousands of differentially expressed genes in this process, and from these we chose 173 candidate genes, of which 98 genes were involved in cell differentiation, 19 were involved in the metabolic process, and 56 were involved in the differentiation and metabolic processes, like GAL9, AMH, PLK1, and PSMD7 and so on. In addition, we found that 18 key signaling pathways were involved mainly in cell proliferation, differentiation, and signal transduction processes like TGF-β, Notch, and Jak-STAT. Further exploration found that the candidate gene expression patterns were the same between in vitro induction experiments and transcriptome results. Our results yield clues to the mechanistic basis of male germ cell differentiation and provide an important reference for further studies. PMID:25847247

  5. A functional genomic screen in planarians identifies novel regulators of germ cell development

    PubMed Central

    Wang, Yuying; Stary, Joel M.; Wilhelm, James E.; Newmark, Phillip A.

    2010-01-01

    Germ cells serve as intriguing examples of differentiated cells that retain the capacity to generate all cell types of an organism. Here we used functional genomic approaches in planarians to identify genes required for proper germ cell development. We conducted microarray analyses and in situ hybridization to discover and validate germ cell-enriched transcripts, and then used RNAi to screen for genes required for discrete stages of germ cell development. The majority of genes we identified encode conserved RNA-binding proteins, several of which have not been implicated previously in germ cell development. We also show that a germ cell-specific subunit of the conserved transcription factor CCAAT-binding protein/nuclear factor-Y is required for maintaining spermatogonial stem cells. Our results demonstrate that conserved transcriptional and post-transcriptional mechanisms regulate germ cell development in planarians. These findings suggest that studies of planarians will inform our understanding of germ cell biology in higher organisms. PMID:20844018

  6. Germ-cell malignant tumours in father and son.

    PubMed Central

    Musa, M. B.

    1975-01-01

    Germ-cell malignant tumours occurred in a man and his son. The father, who had a teratoma of the right testicle removed 24 years ago, is presently alive and well. The son, who had a choriocarcinoma presenting as an abdominal mass, possibly originating in the testicle, died within 7 months of the diagnosis with metastases in the lungs, liver and retroperitoneum. This report documents the third such case of germ-cell neoplasms occurring in father and son. Images FIG. 1 FIG. 2 FIG. 3 PMID:1168534

  7. Paternity in patients with bilateral testicular germ cell tumors.

    PubMed

    Heidenreich, A; Vorreuther, R; Neubauer, S; Zumbe, J; Engelmann, U H

    1997-01-01

    We report on the finding of paternity in 1 patient with metachronous bilateral testis germ cell tumor (BTGCT) and in another patient with a unilateral testicular germ cell tumor and contralateral carcinoma in situ (CIS). These cases demonstrate that patients with BTGCT or CIS in their solitary testicle are not necessarily infertile. Surveillance might be a therapeutic modality in patients with contralateral CIS and active spermatogenesis and the desire for paternity assumed that they are included in close follow-up protocols. PMID:9076475

  8. Development of a new approach for targeted gene editing in primordial germ cells using TALENs in Xenopus

    PubMed Central

    Nakajima, Keisuke; Yaoita, Yoshio

    2015-01-01

    ABSTRACT A gene of interest can be efficiently modified using transcription activator-like effector nucleases (TALENs) (Christian et al., 2010;Li et al., 2011). However, if a target gene is essential for development, growth and fertility, use of TALENs with high mutagenic activity in F0 frogs could result in developmental disorders or sterility, which would reduce the number of F1 progeny and make F1 phenotypical analysis difficult. We used the 3′ untranslated region of DEADSouth gene (DS-3′) of Xenopus tropicalis to solve this problem, because the addition of the DS-3′ to mRNA is known to induce primordial germ cell (PGC)-specific expression and reduce the stability in somatic cells of mRNA in Xenopus laevis. At first, we inserted the X. tropicalis DS-3′ downstream of the EGFP termination codon and confirmed that the EGFP expression was specifically detected in PGCs for three weeks. Therefore, we inserted the DS-3′ downstream of the termination codon of the TALEN coding sequence. The tyrosinase gene was selected as the target gene for TALEN because the bi-allelic mutation of this gene is easily discernible by the albino phenotype. When fertilized eggs were microinjected with TALEN mRNAs fused to the DS-3′, their sperm and oocytes had a high rate (84–100%) of target-gene modification in contrast to the lower rate (0–45%) of nucleotide alteration observed in somatic cells. PMID:25661867

  9. Germ cell neoplasia in situ (GCNIS): evolution of the current nomenclature for testicular pre-invasive germ cell malignancy.

    PubMed

    Berney, Daniel M; Looijenga, Leendert H J; Idrees, Muhammad; Oosterhuis, J Wolter; Rajpert-De Meyts, Ewa; Ulbright, Thomas M; Skakkebaek, Niels E

    2016-07-01

    The pre-invasive lesion associated with post-pubertal malignant germ cell tumours of the testis was first recognized in the early 1970s and confirmed by a number of observational and follow-up studies. Until this year, this scientific story has been confused by resistance to the entity and disagreement on its name. Initially termed 'carcinoma in situ' (CIS), it has also been known as 'intratubular germ cell neoplasia, unclassified' (IGCNU) and 'testicular intraepithelial neoplasia' (TIN). In this paper, we review the history of discovery and controversy concerning these names and introduce the reasoning for uniting behind a new name, endorsed unanimously at the World Health Organization (WHO) consensus classification 2016: germ cell neoplasia in situ (GCNIS). PMID:26918959

  10. Germ cell DNA quantification shortly after IR laser radiation.

    PubMed

    Bermúdez, D; Carrasco, F; Diaz, F; Perez-de-Vargas, I

    1991-01-01

    The immediate effect of IR laser radiation on rat germ cells was studied by cytophotometric quantification of the nuclear DNA content in testicular sections. Two different levels of radiation were studied: one according to clinical application (28.05 J/cm2) and another known to increase the germ cell number (46.80 J/cm2). The laser beam induced changes in the germ cell DNA content depending on the cell type, the cell cycle phase and the doses of radiation energy applied. Following irradiation at both doses the percentage of spermatogonia showing a 4c DNA content was increased, while the percentage of these with a 2c DNA content was decreased. Likewise, the percentages of primary spermatocytes with a DNA content equal to 4c (at 28.05 J/cm2), between 2c and 4c (at 46.80 J/cm2) and higher than 4c (at both doses) were increased. No change in the mean spermatid DNA content was observed. Nevertheless, at 46.80 J/cm2 the percentages of elongated spermatids with a c or 2c DNA content differed from the controls. Data show that, even at laser radiation doses used in therapy, the germ cell DNA content is increased shortly after IR laser radiation. PMID:1772145

  11. Stem cells and germ cells: microRNA and gene expression signatures.

    PubMed

    Dyce, Paul William; Toms, Derek; Li, Julang

    2010-04-01

    The study of primordial germ cell development in vivo is hampered by their low numbers and inaccessibility. Recent research has shown the ability of embryonic and adult stem cells to differentiate into primordial germ cells and more mature gametes and this generation of germ cells in vitro may be an attractive model for their study. One of the biggest challenges facing in vitro differentiation of stem cells into primordial germ cells is the lack of markers to clearly distinguish the two. As both cell types originate early in embryonic development they share many pluripotent markers such as OCT4, VASA, FRAGILIS, and NANOG. Genome wide microarray profiling has been used to identify transcriptome patterns unique to primordial germ cells. A more thorough analysis of the temporal and quantitative expression of a panel of genes may be more robust in distinguishing these two cell populations. MicroRNAs, short RNA molecules that have been shown to regulate translation through interactions with mRNA transcripts, have also recently come under investigation for the role they may play in pluripotency. Attempts to elucidate key microRNAs responsible for both stem cell and primordial germ cell characteristics have recently been undertaken. Unique microRNAs, either individually or as global profiles, may also help to distinguish differentiated primordial germ cells from stem cells in vitro. This review will examine gene expression and microRNA signatures in stem cells and germ cells as ways to distinguish these closely related cell types. PMID:20183803

  12. Declaring the Existence of Human Germ-Cell Mutagens

    EPA Science Inventory

    After more than 80 years of searching for human germ-cell mutagens, I think that sufficient evidence already exists for a number of agents to be so considered, and definitive confirmation seems imminent due to the application ofrecently developed genomic techniques. In preparatio...

  13. Delayed BMP4 exposure increases germ cell differentiation in mouse embryonic stem cells.

    PubMed

    Talaei-Khozani, Tahereh; Zarei Fard, Nehleh; Bahmanpour, Soghra; Jaberipour, Mansoureh; Hosseini, Ahmah; Esmaeilpour, Tahereh

    2014-01-01

    Fate mapping studies have revealed that bone morphogenetic protein 4 (BMP4) signaling has a key role in segregation of primordial germ cells from proximal epiblast. Adding BMP4 to the culture media of embryonic stem (ES) cells could induce expression of germ cell markers; however, to provide a desired number of germ cells has remained a challenge. In the current study, we intended to establish an in vitro system to obtain reliable germ cells derived from ES cells. Differentiation was induced in ES cells via embryoid body (EB) and monolayer culture system. Cells were cultured with BMP4 from the beginning (++BMP4) or after 48 hours (+BMP4) of culturing for five days. The cultures were assessed for alkaline phosphatase (ALP) activity, expression of Oct4, Mvh and c-kit. In EB culture protocol, the expression of Mvh, Oct4 and ALP activity significantly increased in +BMP4 culture condition, but a significant down-regulation in the expression of germ cell markers was shown in ++BMP4 condition compared with the control group. Parallel differentiation experiments using monolayer culture system indicated the number of putative germ cells did not change. In the current study, we compared two differentiation methods (EB and monolayer) to achieve an optimal germ cell production. The EBs with a short exposure time period to BMP4, showing typical characteristics of germ cells. Therefore, our approach provides a strategy for the production of germline cells from ES cells. PMID:24969978

  14. DNA Analysis in Samples From Younger Patients With Germ Cell Tumors and Their Parents or Siblings

    ClinicalTrials.gov

    2016-04-07

    Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Ovarian Choriocarcinoma; Ovarian Embryonal Carcinoma; Ovarian Mixed Germ Cell Tumor; Ovarian Teratoma; Ovarian Yolk Sac Tumor; Testicular Choriocarcinoma; Testicular Embryonal Carcinoma; Testicular Seminoma; Testicular Teratoma; Testicular Yolk Sac Tumor

  15. The role of dead-end in germ-cell tumor development.

    PubMed

    Zhu, Rui; Bhattacharya, Chitralekha; Matin, Angabin

    2007-12-01

    Testicular germ-cell tumors occur in human males of all age groups, from infants to men over 50 years old. Most commonly, germ-cell tumors (generally known as testicular cancer) occur in young males between the ages of 15 to 35 years. The tumor tissues are usually histologically diverse, and testicular tumors that occur in the different age groups tend to be of specific histological subtypes. Most germ-cell tumors originate from primordial germ cells during embryonic development, although the progression and eventual detection of the disease occurs decades later in humans. Mouse strains spontaneously develop a specific subtype of testicular germ-cell tumors, the type I germ-cell tumors, and these tumors are similar to the germ-cell tumors (or teratomas) that occur in human infants. Some mouse strains, such as the 129-Ter strain, have extremely high germ-cell tumor incidences, making such strains ideal for genetic and biological studies of germ cell-tumor development. Here a brief overview of the recently identified genetic defect in the Ter strain, inactivation of the dead-end (Dnd1) gene, and the ongoing studies on Dnd1 to understand its role in germ-cell and germ cell-tumor development, are provided. PMID:17905939

  16. Models of germ cell development and their application for toxicity studies.

    PubMed

    Ferreira, Daniel W; Allard, Patrick

    2015-10-01

    Germ cells are unique in their ability to transfer genetic information and traits from generation to generation. As such, the proper development of germ cells and the integrity of their genome are paramount to the health of organisms and the survival of species. Germ cells are also exquisitely sensitive to environmental influences although the testing of germ cell toxicity, especially in females, has proven particularly challenging. In this review, we first describe the remarkable odyssey of germ cells in mammals, with an emphasis on the female germline, from their initial specification early during embryogenesis to the generation of mature gametes in adults. We also describe the current methods used in germ cell toxicity testing and their limitations in examining the complex features of mammalian germ cell development. To bypass these challenges, we propose the use of alternative model systems such as Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans, and in vitro germ cell methods that have distinct advantages over traditional toxicity models. We discuss the benefits and limitations of each approach, their application to germ cell toxicity studies, and the need for computational approaches to maximize the usefulness of these models. Together, the inclusion of these alternative germ cell toxicity models will be invaluable for the examination of stages not easily accessible in mammals as well as the large scale, high-throughput investigation of germ cell toxicity. PMID:25821157

  17. Prmt5 is required for germ cell survival during spermatogenesis in mice

    PubMed Central

    Wang, Yanbo; Zhu, Tianxiang; Li, Qiuling; Liu, Chunyi; Han, Feng; Chen, Min; Zhang, Lianjun; Cui, Xiuhong; Qin, Yan; Bao, Shilai; Gao, Fei

    2015-01-01

    During germ cell development, epigenetic modifications undergo extensive remodeling. Abnormal epigenetic modifications usually result in germ cell loss and reproductive defect. Prmt5 (Protein arginine methyltransferase 5) encodes a protein arginine methyltransferase which has been demonstrated to play important roles in germ cell development during embryonic stages. In the present study, we found that Prmt5 was also abundantly expressed in male germ cells after birth. Inactivation of this gene by crossing with Stra8-Cre transgenic mice resulted in germ cell loss during spermatogenesis. Further study revealed that the germ cell development was grossly normal before P10. However, most of the germ cells in Prmt5Δ/f; Stra8-Cre mice were blocked at meiotic stage. The expression of meiosis associated genes was reduced in Prmt5Δ/f; Stra8-Cre testes compared to control testes at P10. γH2AX was detected in sex body of control germ cells at P12, whereas multiple foci were observed in Prmt5-deficient germ cells. Further study revealed that H4R3me2s was virtually absent in germ cells after Prmt5 inactivation. The results of this study indicate that Prmt5 also plays important roles in germ cell development during spermatogenesis. PMID:26072710

  18. On the number of founding germ cells in humans

    PubMed Central

    Zheng, Chang-Jiang; Luebeck, E Georg; Byers, Breck; Moolgavkar, Suresh H

    2005-01-01

    Background The number of founding germ cells (FGCs) in mammals is of fundamental significance to the fidelity of gene transmission between generations, but estimates from various methods vary widely. In this paper we obtain a new estimate for the value in humans by using a mathematical model of germ cell development that depends on available oocyte counts for adult women. Results The germline-development model derives from the assumption that oogonial proliferation in the embryonic stage starts with a founding cells at t = 0 and that the subsequent proliferation can be defined as a simple stochastic birth process. It follows that the population size X(t) at the end of germline expansion (around the 5th month of pregnancy in humans; t = 0.42 years) is a random variable with a negative binomial distribution. A formula based on the expectation and variance of this random variable yields a moment-based estimate of a that is insensitive to the progressive reduction in oocyte numbers due to their utilization and apoptosis at later stages of life. In addition, we describe an algorithm for computing the maximum likelihood estimation of the FGC population size (a), as well as the rates of oogonial division and loss to apoptosis. Utilizing both of these approaches to evaluate available oocyte-counting data, we have obtained an estimate of a = 2 – 3 for Homo sapiens. Conclusion The estimated number of founding germ cells in humans corresponds well with values previously derived from chimerical or mosaic mouse data. These findings suggest that the large variation in oocyte numbers between individual women is consistent with a smaller founding germ cell population size than has been estimated by cytological analyses. PMID:16120211

  19. NUT protein immunoreactivity in ovarian germ cell tumours.

    PubMed

    Iacobelli, J F; Charles, A K; Crook, M; Stewart, C J R

    2015-02-01

    The aim of this study was to investigate NUT (nuclear protein in the testis) expression in ovarian germ cell tumours (GCTs). Immunostaining for NUT protein was performed in 10 mature cystic teratomas and in 49 malignant ovarian GCTs including 15 pure dysgerminomas, six dysgerminomas associated with gonadoblastoma, nine yolk sac tumours, 12 immature teratomas, and seven mixed malignant tumours. Only nuclear staining was considered a positive finding although cytoplasmic staining was noted when present. Thirty-seven (76%) malignant GCTs were NUT positive but staining was usually of weak to moderate intensity and observed in a relatively small proportion of neoplastic cells. Staining in immature teratomas and yolk sac tumours was restricted to foci of hepatoid and intestinal/glandular differentiation, where both nuclear and cytoplasmic reactivity were observed. In dysgerminoma associated with gonadoblastoma only the in situ and invasive germ cell elements were NUT positive. Nuclear staining was not seen in benign teratomas. Most malignant ovarian GCTs express NUT protein, albeit focally, and this should be considered when evaluating immunostaining in the differential diagnosis of poorly differentiated malignancies, particularly NUT midline carcinoma. Since NUT protein appears to play a role in normal germ cell maturation it may influence intestinal or hepatoid differentiation within malignant GCTs. PMID:25551299

  20. Meiotic germ cells antagonize mesonephric cell migration and testis cord formation in mouse gonads

    PubMed Central

    Yao, Humphrey H.-C.; DiNapoli, Leo; Capel, Blanche

    2014-01-01

    Summary The developmental fate of primordial germ cells in the mammalian gonad depends on their environment. In the XY gonad, Sry induces a cascade of molecular and cellular events leading to the organization of testis cords. Germ cells are sequestered inside testis cords by 12.5 dpc where they arrest in mitosis. If the testis pathway is not initiated, germ cells spontaneously enter meiosis by 13.5 dpc, and the gonad follows the ovarian fate. We have previously shown that some testis-specific events, such as mesonephric cell migration, can be experimentally induced into XX gonads prior to 12.5 dpc. However, after that time, XX gonads are resistant to the induction of cell migration. In current experiments, we provide evidence that this effect is dependent on XX germ cells rather than on XX somatic cells. We show that, although mesonephric cell migration cannot be induced into normal XX gonads at 14.5 dpc, it can be induced into XX gonads depleted of germ cells. We also show that when 14.5 dpc XX somatic cells are recombined with XY somatic cells, testis cord structures form normally; however, when XX germ cells are recombined with XY somatic cells, cord structures are disrupted. Sandwich culture experiments suggest that the inhibitory effect of XX germ cells is mediated through short-range interactions rather than through a long-range diffusible factor. The developmental stage at which XX germ cells show a disruptive effect on the male pathway is the stage at which meiosis is normally initiated, based on the immunodetection of meiotic markers. We suggest that at the stage when germ cells commit to meiosis, they reinforce ovarian fate by antagonizing the testis pathway. PMID:14561636

  1. Updates in the management of ovarian germ cell tumors.

    PubMed

    Matei, Daniela; Brown, Jubilee; Frazier, Lindsay

    2013-01-01

    Ovarian germ cell tumors are rare events at all ages-in pediatrics, adolescence, and during young adulthood. Combining the knowledge and experience of pediatric and gynecologic oncologists can lead to better outcomes for all. In this review, we intend to present the latest consensus on management of women and children with this disease and highlight the opportunities for collaboration and clinical research going forward. PMID:23714505

  2. The diversity of nanos expression in echinoderm embryos supports different mechanisms in germ cell specification.

    PubMed

    Fresques, Tara; Swartz, Steven Zachary; Juliano, Celina; Morino, Yoshiaki; Kikuchi, Mani; Akasaka, Koji; Wada, Hiroshi; Yajima, Mamiko; Wessel, Gary M

    2016-07-01

    Specification of the germ cell lineage is required for sexual reproduction in all animals. However, the timing and mechanisms of germ cell specification is remarkably diverse in animal development. Echinoderms, such as sea urchins and sea stars, are excellent model systems to study the molecular and cellular mechanisms that contribute to germ cell specification. In several echinoderm embryos tested, the germ cell factor Vasa accumulates broadly during early development and is restricted after gastrulation to cells that contribute to the germ cell lineage. In the sea urchin, however, the germ cell factor Vasa is restricted to a specific lineage by the 32-cell stage. We therefore hypothesized that the germ cell specification program in the sea urchin/Euechinoid lineage has evolved to an earlier developmental time point. To test this hypothesis we determined the expression pattern of a second germ cell factor, Nanos, in four out of five extant echinoderm clades. Here we find that Nanos mRNA does not accumulate until the blastula stage or later during the development of all other echinoderm embryos except those that belong to the Echinoid lineage. Instead, Nanos is expressed in a restricted domain at the 32-128 cell stage in Echinoid embryos. Our results support the model that the germ cell specification program underwent a heterochronic shift in the Echinoid lineage. A comparison of Echinoid and non-Echinoid germ cell specification mechanisms will contribute to our understanding of how these mechanisms have changed during animal evolution. PMID:27402572

  3. Detection of phase specificity of in vivo germ cell mutagens in an in vitro germ cell system.

    PubMed

    Habas, Khaled; Anderson, Diana; Brinkworth, Martin

    2016-04-15

    In vivo tests for male reproductive genotoxicity are time consuming, resource-intensive and their use should be minimised according to the principles of the 3Rs. Accordingly, we investigated the effects in vitro, of a variety of known, phase-specific germ cell mutagens, i.e., pre-meiotic, meiotic, and post-meiotic genotoxins, on rat spermatogenic cell types separated using Staput unit-gravity velocity sedimentation, evaluating DNA damage using the Comet assay. N-ethyl-N-nitrosourea (ENU), N-methyl-N-nitrosourea (MNU) (spermatogenic phase), 6-mercaptopurine (6-MP) and 5-bromo-2'-deoxy-uridine (5-BrdU) (meiotic phase), methyl methanesulphonate (MMS) and ethyl methanesulphonate (EMS) (post-meiotic phase) were selected for use as they are potent male rodent, germ cell mutagens in vivo. DNA damage was detected directly using the Comet assay and indirectly using the TUNEL assay. Treatment of the isolated cells with ENU and MNU produced the greatest concentration-related increase in DNA damage in spermatogonia. Spermatocytes were most sensitive to 6-MP and 5-BrdU while spermatids were particularly susceptible to MMS and EMS. Increases were found when measuring both Olive tail moment (OTM) and% tail DNA, but the greatest changes were in OTM. Parallel results were found with the TUNEL assay, which showed highly significant, concentration dependent effects of all these genotoxins on spermatogonia, spermatocytes and spermatids in the same way as for DNA damage. The specific effects of these chemicals on different germ cell types matches those produced in vivo. This approach therefore shows potential for use in the detection of male germ cell genotoxicity and could contribute to the reduction of the use of animals in such toxicity assays. PMID:27059372

  4. POMB/ACE chemotherapy for mediastinal germ cell tumours.

    PubMed

    Bower, M; Brock, C; Holden, L; Nelstrop, A; Makey, A R; Rustin, G J; Newlands, E S

    1997-05-01

    Mediastinal germ cell tumours (MGCT) are rare and most published series reflect the experiences of individual institutions over many years. Since 1979, we have treated 16 men (12 non-seminomatous germ cell tumours and 4 seminomas) with newly diagnosed primary MGCT with POMB/ACE chemotherapy and elective surgical resection of residual masses. This approach yielded complete remissions in 15/16 (94%) patients. The median follow-up was 6.0 years and no relapses occurred more than 2 years after treatment. The 5 year overall survival in the non-seminomatous germ cell tumours (NSGCT) is 73% (95% confidence interval 43-90%). One patient with NSGCT developed drug-resistant disease and died without achieving remission and 2 patients died of relapsed disease. In addition, 4 patients with bulky and/or metastatic seminoma were treated with POMB/ACE. One died of treatment-related neutropenic sepsis in complete remission and one died of relapsed disease. Finally, 4 patients (2 NSGCT and 2 seminomas) referred at relapse were treated with POMB/ACE and one was successfully salvaged. The combination of POMB/ACE chemotherapy and surgery is effective management for MGCT producing high long-term survival rates. PMID:9291802

  5. Development of germ cell neoplasia in situ in chinchilla rabbits.

    PubMed

    Vigueras-Villaseñor, Rosa María; Montelongo Solís, Paola; Chávez-Saldaña, Margarita; Gutiérrez-Pérez, Oscar; Cortés Trujillo, Lucero; Rojas-Castañeda, Julio César

    2016-05-01

    The present study was designed to describe the development of germ cell neoplasia in situ in Chinchilla rabbit by administration of estradiol. The study was performed in rabbits distributed into two groups: control and 17 β-estradiol. The determination of histological alterations and POU5F1 and c-kit proteins employed as biomarkers for the diagnosis of this neoplasia was carried out. Testicular descent and complete spermatogenesis were observed in the control group. The protein biomarkers were negative. However, in the rabbits treated with estradiol, the testes remained undescended with the gonocytes undifferentiated to spermatogonia. There were histological lesions owing to germ cell neoplasia in situ and positive to POU5F1 and c-kit proteins. These findings indicate that the chinchilla rabbit is an ideal model to study this neoplasia in which the histological characteristics and biomarkers of the disease could be clearly observed. Using this model we suggested that the persisting gonocytes could be responsible for the development of germ cell neoplasia in situ. PMID:26617392

  6. Telomere homeostasis in mammalian germ cells: a review.

    PubMed

    Reig-Viader, Rita; Garcia-Caldés, Montserrat; Ruiz-Herrera, Aurora

    2016-06-01

    Telomeres protect against genome instability and participate in chromosomal movements during gametogenesis, especially in meiosis. Thus, maintaining telomere structure and telomeric length is essential to both cell integrity and the production of germ cells. As a result, alteration of telomere homeostasis in the germ line may result in the generation of aneuploid gametes or gametogenesis disruption, triggering fertility problems. In this work, we provide an overview on fundamental aspects of the literature regarding the organization of telomeres in mammalian germ cells, paying special attention to telomere structure and function, as well as the maintenance of telomeric length during gametogenesis. Moreover, we discuss the different roles recently described for telomerase and TERRA in maintaining telomere functionality. Finally, we review how new findings in the field of reproductive biology underscore the role of telomere homeostasis as a potential biomarker for infertility. Overall, we anticipate that the study of telomere stability and equilibrium will contribute to improve diagnoses of patients; assess the risk of infertility in the offspring; and in turn, find new treatments. PMID:26525972

  7. Tre1, a G Protein-Coupled Receptor, Directs Transepithelial Migration of Drosophila Germ Cells

    PubMed Central

    2003-01-01

    In most organisms, germ cells are formed distant from the somatic part of the gonad and thus have to migrate along and through a variety of tissues to reach the gonad. Transepithelial migration through the posterior midgut (PMG) is the first active step during Drosophila germ cell migration. Here we report the identification of a novel G protein-coupled receptor (GPCR), Tre1, that is essential for this migration step. Maternal tre1 RNA is localized to germ cells, and tre1 is required cell autonomously in germ cells. In tre1 mutant embryos, most germ cells do not exit the PMG. The few germ cells that do leave the midgut early migrate normally to the gonad, suggesting that this gene is specifically required for transepithelial migration and that mutant germ cells are still able to recognize other guidance cues. Additionally, inhibiting small Rho GTPases in germ cells affects transepithelial migration, suggesting that Tre1 signals through Rho1. We propose that Tre1 acts in a manner similar to chemokine receptors required during transepithelial migration of leukocytes, implying an evolutionarily conserved mechanism of transepithelial migration. Recently, the chemokine receptor CXCR4 was shown to direct migration in vertebrate germ cells. Thus, germ cells may more generally use GPCR signaling to navigate the embryo toward their target. PMID:14691551

  8. Primary Malignant Mixed Germ Cell Tumour with Squamous Cell Carcinoma of the Mandible; A Rare Entity

    PubMed Central

    Paul, Arun; Parmar, Harshad; Chacko, Rabin

    2015-01-01

    Germ cell Tumours (GCT) are neoplasm derived from germ cells. GCT usually occurs inside the gonads. Extragonadal GCT’s are rare. Most common GCT associated with head and neck region are the teratomas. Of the few teratomas found in the head and neck, malignant transformation of a teratomatous element is very uncommon, and primary bone involvement within the head and neck is even rare. We present a case of primary malignant mixed germ cell Tumour involving the mandible, the present case presented malignant transformation of the epithelial component showing foci of squamous cell carcinoma within the GCT. PMID:26266228

  9. Generation of exogenous germ cells in the ovaries of sterile NANOS3-null beef cattle

    PubMed Central

    Ideta, Atsushi; Yamashita, Shiro; Seki-Soma, Marie; Yamaguchi, Ryosaku; Chiba, Shiori; Komaki, Haruna; Ito, Tetsuya; Konishi, Masato; Aoyagi, Yoshito; Sendai, Yutaka

    2016-01-01

    Blastocyst complementation (BC) systems have enabled in vivo generation of organs from allogeneic pluripotent cells, compensating for an empty germ cell niche in gene knockout (KO) animals. Here, we succeeded in producing chimeric beef cattle (Wagyu) by transferring allogenic germ cells into ovaries using somatic cell nuclear transfer and BC technology. The KO of NANOS3 (NANOS3−/−) in Wagyu bovine ovaries produced a complete loss of germ cells. Holstein blastomeres (NANOS3+/+) were injected into NANOS3−/− Wagyu embryos. Subsequently, exogenous germ cells (NANOS3+/+) were identified in the NANOS3−/− ovary. These results clearly indicate that allogeneic germ cells can be generated in recipient germ cell-free gonads using cloning and BC technologies. PMID:27117862

  10. Generation of exogenous germ cells in the ovaries of sterile NANOS3-null beef cattle.

    PubMed

    Ideta, Atsushi; Yamashita, Shiro; Seki-Soma, Marie; Yamaguchi, Ryosaku; Chiba, Shiori; Komaki, Haruna; Ito, Tetsuya; Konishi, Masato; Aoyagi, Yoshito; Sendai, Yutaka

    2016-01-01

    Blastocyst complementation (BC) systems have enabled in vivo generation of organs from allogeneic pluripotent cells, compensating for an empty germ cell niche in gene knockout (KO) animals. Here, we succeeded in producing chimeric beef cattle (Wagyu) by transferring allogenic germ cells into ovaries using somatic cell nuclear transfer and BC technology. The KO of NANOS3 (NANOS3(-/-)) in Wagyu bovine ovaries produced a complete loss of germ cells. Holstein blastomeres (NANOS3(+/+)) were injected into NANOS3(-/-) Wagyu embryos. Subsequently, exogenous germ cells (NANOS3(+/+)) were identified in the NANOS3(-/-) ovary. These results clearly indicate that allogeneic germ cells can be generated in recipient germ cell-free gonads using cloning and BC technologies. PMID:27117862

  11. BMP signaling is required for the generation of primordial germ cells in an insect

    PubMed Central

    Donoughe, Seth; Nakamura, Taro; Ewen-Campen, Ben; Green, Delbert A.; Henderson, Lory; Extavour, Cassandra G.

    2014-01-01

    Two modes of germ cell formation are known in animals. Specification through maternally inherited germ plasm occurs in many well-characterized model organisms, but most animals lack germ plasm by morphological and functional criteria. The only known alternative mechanism is induction, experimentally described only in mice, which specify germ cells through bone morphogenetic protein (BMP) signal-mediated induction of a subpopulation of mesodermal cells. Until this report, no experimental evidence of an inductive germ cell signal for specification has been available outside of vertebrates. Here we provide functional genetic experimental evidence consistent with a role for BMP signaling in germ cell formation in a basally branching insect. We show that primordial germ cells of the cricket Gryllus bimaculatus transduce BMP signals and require BMP pathway activity for their formation. Moreover, increased BMP activity leads to ectopic and supernumerary germ cells. Given the commonality of BMP signaling in mouse and cricket germ cell induction, we suggest that BMP-based germ cell formation may be a shared ancestral mechanism in animals. PMID:24591634

  12. BMP signaling is required for the generation of primordial germ cells in an insect.

    PubMed

    Donoughe, Seth; Nakamura, Taro; Ewen-Campen, Ben; Green, Delbert A; Henderson, Lory; Extavour, Cassandra G

    2014-03-18

    Two modes of germ cell formation are known in animals. Specification through maternally inherited germ plasm occurs in many well-characterized model organisms, but most animals lack germ plasm by morphological and functional criteria. The only known alternative mechanism is induction, experimentally described only in mice, which specify germ cells through bone morphogenetic protein (BMP) signal-mediated induction of a subpopulation of mesodermal cells. Until this report, no experimental evidence of an inductive germ cell signal for specification has been available outside of vertebrates. Here we provide functional genetic experimental evidence consistent with a role for BMP signaling in germ cell formation in a basally branching insect. We show that primordial germ cells of the cricket Gryllus bimaculatus transduce BMP signals and require BMP pathway activity for their formation. Moreover, increased BMP activity leads to ectopic and supernumerary germ cells. Given the commonality of BMP signaling in mouse and cricket germ cell induction, we suggest that BMP-based germ cell formation may be a shared ancestral mechanism in animals. PMID:24591634

  13. ELMO1 signaling in apoptotic germ cell clearance and spermatogenesis.

    PubMed

    Elliott, Michael R; Ravichandran, Kodi S

    2010-10-01

    Apoptosis and the subsequent removal of dying cells are crucial processes for tissue development and maintenance. Although we are beginning to understand the signaling pathways that control the phagocytic clearance of apoptotic cells, the physiological relevance of these pathways is lacking. During spermatogenesis, over half of the developing germ cells eventually die by apoptosis, yet the signaling pathways that regulate the phagocytic clearance of these dying cells or the impact of this clearance on development and maintenance of the germ cell population is not well understood. The ELMO1/Dock180 proteins form an evolutionarily conserved signaling module that functions as a bipartite guanine nucleotide exchange factor for the small GTPase Rac. The subsequent Rac-dependent cytoskeletal changes play an important role in the physical engulfment of apoptotic cells. Recent findings demonstrate an in vivo role for ELMO1-dependent clearance in the testes, with implications for spermatogenesis. Here we will discuss the role of apoptotic cell clearance during spermatogenesis, with a particular emphasis on ELMO1/Dock180 signaling. PMID:20958313

  14. Human somatic cells subjected to genetic induction with six germ line-related factors display meiotic germ cell-like features

    PubMed Central

    Medrano, Jose V.; Martínez-Arroyo, Ana M.; Míguez, Jose M.; Moreno, Inmaculada; Martínez, Sebastián; Quiñonero, Alicia; Díaz-Gimeno, Patricia; Marqués-Marí, Ana I.; Pellicer, Antonio; Remohí, Jose; Simón, Carlos

    2016-01-01

    The in vitro derivation of human germ cells has attracted interest in the last years, but their direct conversion from human somatic cells has not yet been reported. Here we tested the ability of human male somatic cells to directly convert into a meiotic germ cell-like phenotype by inducing them with a combination of selected key germ cell developmental factors. We started with a pool of 12 candidates that were reduced to 6, demonstrating that ectopic expression of the germ line-related genes PRDM1, PRDM14, LIN28A, DAZL, VASA and SYCP3 induced direct conversion of somatic cells (hFSK (46, XY), and hMSC (46, XY)) into a germ cell-like phenotype in vitro. Induced germ cell-like cells showed a marked switch in their transcriptomic profile and expressed several post-meiotic germ line related markers, showed meiotic progression, evidence of epigenetic reprogramming, and approximately 1% were able to complete meiosis as demonstrated by their haploid status and the expression of several post-meiotic markers. Furthermore, xenotransplantation assays demonstrated that a subset of induced cells properly colonize the spermatogonial niche. Knowledge obtained from this work can be used to create in vitro models to study gamete-related diseases in humans. PMID:27112843

  15. Insights into female germ cell biology: from in vivo development to in vitro derivations

    PubMed Central

    Jung, Dajung; Kee, Kehkooi

    2015-01-01

    Understanding the mechanisms of human germ cell biology is important for developing infertility treatments. However, little is known about the mechanisms that regulate human gametogenesis due to the difficulties in collecting samples, especially germ cells during fetal development. In contrast to the mitotic arrest of spermatogonia stem cells in the fetal testis, female germ cells proceed into meiosis and began folliculogenesis in fetal ovaries. Regulations of these developmental events, including the initiation of meiosis and the endowment of primordial follicles, remain an enigma. Studying the molecular mechanisms of female germ cell biology in the human ovary has been mostly limited to spatiotemporal characterizations of genes or proteins. Recent efforts in utilizing in vitro differentiation system of stem cells to derive germ cells have allowed researchers to begin studying molecular mechanisms during human germ cell development. Meanwhile, the possibility of isolating female germline stem cells in adult ovaries also excites researchers and generates many debates. This review will mainly focus on presenting and discussing recent in vivo and in vitro studies on female germ cell biology in human. The topics will highlight the progress made in understanding the three main stages of germ cell developments: namely, primordial germ cell formation, meiotic initiation, and folliculogenesis. PMID:25652637

  16. Germ Cell Tumors in Adolescents and Young Adults.

    PubMed

    Calaminus, Gabriele; Joffe, Jonathan

    2016-01-01

    Germ cell tumors (GCTs) represent a group of biologically complex malignancies that affect patients at different sites within the body and at different ages. The varying nature of these tumors reflects their cell of origin which is the primordial germ cell, which normally gives rise to ovarian and testicular egg and sperm producing cells. These cells retain an ability to give rise to all types of human tissues, and this is illustrated by the different kinds of GCTs that occur. In adolescent and young adult (AYA) patients, GCTs predominantly present as testicular, ovarian or mediastinal primary GCTs, and represent some of the most complex therapeutic challenges within any AYA practice. The varying types of GCTs, defined by primary site and/or age at presentation, can look very similar microscopically. However, there is growing evidence that they may have different molecular characteristics, different biology and different requirements for curative treatments. Whilst in adult testicular GCTs there is evidence for an environmental cause during fetal development and a genetic component, these causative factors are much less well understood in other GCTs. GCTs are some of the most curable cancers in adults, but some patients exhibit resistance to standard treatments. Because of this, today's clinical research is directed at understanding how to best utilize toxic therapies and promote healthy survivorship. This chapter explores the biology, behavior and treatment of GCTs and discusses how the AYA group of GCTs may hold some of the keys to understanding fundamental unanswered questions of biological variance and curability in GCTs. PMID:27595361

  17. Autophagy is a cell survival program for female germ cells in the murine ovary.

    PubMed

    Gawriluk, Thomas R; Hale, Amber N; Flaws, Jodi A; Dillon, Christopher P; Green, Douglas R; Rucker, Edmund B

    2011-06-01

    It is estimated that infertility affects 15-20% of couples and can arise from female or male reproductive defects. Mouse models have ascribed roles to over 100 genes in the maintenance of female fertility. Although previous models have determined roles for apoptosis in male and female fertility, we find that compromised autophagy within the perinatal ovary, through the loss of Becn1 or Atg7, results in the premature loss of female germ cells. Becn1(+/-) ovaries have a 56% reduction of germ cells compared with control ovaries at post-natal day 1, whereas Atg7(-/-) ovaries lack discernable germ cells at this stage. Thus autophagy appears to be a cell survival mechanism to maintain the endowment of female germ cells prior to establishing primordial follicle pools in the ovary. PMID:21464117

  18. Spectrum of germ cell tumors: from head to toe.

    PubMed

    Ueno, Teruko; Tanaka, Yumiko Oishi; Nagata, Michio; Tsunoda, Hajime; Anno, Izumi; Ishikawa, Shigemi; Kawai, Koji; Itai, Yuji

    2004-01-01

    Germ cell tumors (GCTs) occur most frequently in the gonads and are relatively rare in other sites, such as the pineal gland, neurohypophysis, mediastinum, and retroperitoneum. GCTs are thought to originate from primordial germ cells, which migrate to the primitive gonadal glands in the urogenital ridge. Extragonadal GCTs might also originate from these cells when the cells are sequestered during their migration. Pathologic subtypes of GCTs vary, and the prevalence of mixed tumors is high. These factors produce a diversity of radiologic findings and make prospective radiologic diagnosis difficult in many cases. However, similar radiologic findings have been observed in pathologically equivalent tumors in varying sites. Seminomas appear as uniformly solid, lobulated masses with fibrovascular septa that enhance intensely. Nonseminomatous GCTs appear as heterogeneous masses with areas of necrosis, hemorrhage, or cystic degeneration. Fat and calcifications are hallmarks of teratomas, most of which are benign. In immature teratomas, scattered fat and calcification within larger solid components are occasionally seen. These imaging characteristics reflect the pathologic features of each tumor, and histologically similar GCTs at varying sites have similar radiologic features. Knowledge of the pathologic appearances of GCTs and their corresponding radiologic appearances will allow radiologists to diagnose these tumors correctly. PMID:15026588

  19. Study on the Regulatory Mechanism of the Lipid Metabolism Pathways during Chicken Male Germ Cell Differentiation Based on RNA-Seq

    PubMed Central

    Zuo, Qisheng; Li, Dong; Zhang, Lei; Elsayed, Ahmed Kamel; Lian, Chao; Shi, Qingqing; Zhang, Zhentao; Zhu, Rui; Wang, Yinjie; Jin, Kai; Zhang, Yani; Li, Bichun

    2015-01-01

    Here, we explore the regulatory mechanism of lipid metabolic signaling pathways and related genes during differentiation of male germ cells in chickens, with the hope that better understanding of these pathways may improve in vitro induction. Fluorescence-activated cell sorting was used to obtain highly purified cultures of embryonic stem cells (ESCs), primitive germ cells (PGCs), and spermatogonial stem cells (SSCs). The total RNA was then extracted from each type of cell. High-throughput analysis methods (RNA-seq) were used to sequence the transcriptome of these cells. Gene Ontology (GO) analysis and the KEGG database were used to identify lipid metabolism pathways and related genes. Retinoic acid (RA), the end-product of the retinol metabolism pathway, induced in vitro differentiation of ESC into male germ cells. Quantitative real-time PCR (qRT-PCR) was used to detect changes in the expression of the genes involved in the retinol metabolic pathways. From the results of RNA-seq and the database analyses, we concluded that there are 328 genes in 27 lipid metabolic pathways continuously involved in lipid metabolism during the differentiation of ESC into SSC in vivo, including retinol metabolism. Alcohol dehydrogenase 5 (ADH5) and aldehyde dehydrogenase 1 family member A1 (ALDH1A1) are involved in RA synthesis in the cell. ADH5 was specifically expressed in PGC in our experiments and aldehyde dehydrogenase 1 family member A1 (ALDH1A1) persistently increased throughout development. CYP26b1, a member of the cytochrome P450 superfamily, is involved in the degradation of RA. Expression of CYP26b1, in contrast, decreased throughout development. Exogenous RA in the culture medium induced differentiation of ESC to SSC-like cells. The expression patterns of ADH5, ALDH1A1, and CYP26b1 were consistent with RNA-seq results. We conclude that the retinol metabolism pathway plays an important role in the process of chicken male germ cell differentiation. PMID:25658587

  20. Intratubular germ cell neoplasia of the human testis: heterogeneous protein expression and relation to invasive potential

    PubMed Central

    Mitchell, Rod T; Camacho-Moll, Maria; Macdonald, Joni; Anderson, Richard A; Kelnar, Christopher JH; O’Donnell, Marie; Sharpe, Richard M; Smith, Lee B; Grigor, Ken M; Wallace, W Hamish B; Stoop, Hans; Wolffenbuttel, Katja P; Donat, Roland

    2014-01-01

    Testicular germ cell cancer develops from pre-malignant intratubular germ cell neoplasia, unclassified cells that are believed to arise from failure of normal maturation of fetal germ cells from gonocytes (OCT4+/ MAGEA4−) into pre-spermatogonia (OCT4−/MAGEA4+). Intratubular germ cell neoplasia cell subpopulations based on stage of germ cell differentiation have been described, however the importance of these subpopulations in terms of invasive potential has not been reported. We hypothesised that cells expressing an immature (OCT4+/MAGEA4−) germ cell profile would exhibit an increased proliferation rate compared to those with a mature profile (OCT4+/ MAGEA4+). Therefore, we performed triple immunofluorescence and stereology to quantify the different intratubular germ cell neoplasia cell subpopulations, based on expression of germ cell (OCT4, PLAP, AP2γ, MAGEA4, VASA) and proliferation (Ki67) markers, in testis sections from patients with pre-invasive disease, seminoma and non-seminoma. We compared these subpopulations with normal human fetal testis and with seminoma cells. Heterogeneity of protein expression was demonstrated in intratubular germ cell neoplasia cells with respect to gonocyte and spermatogonial markers. It included an embryonic/fetal germ cell subpopulation lacking expression of the definitive intratubular germ cell neoplasia marker OCT4, that did not correspond to a physiological (fetal) germ cell subpopulation. OCT4+/MAGEA4- cells showed a significantly increased rate of proliferation compared with the OCT4+/MAGEA4+ population (12.8 v 3.4%, p<0.0001) irrespective of histological tumour type, reflected in the predominance of OCT4+/MAGEA4− cells in the invasive tumour component. Surprisingly, OCT4+/MAGEA4− cells in patients with pre-invasive disease showed significantly higher proliferation compared to those with seminoma or non-seminoma (18.1 v 10.2 v 7.2%, p<0.05 respectively). In conclusion, this study has demonstrated that OCT4+/MAGEA4

  1. Steel factor controls midline cell death of primordial germ cells and is essential for their normal proliferation and migration.

    PubMed

    Runyan, Christopher; Schaible, Kyle; Molyneaux, Kathleen; Wang, Zhuoqiao; Levin, Linda; Wylie, Christopher

    2006-12-01

    During germ-cell migration in the mouse, the dynamics of embryo growth cause many germ cells to be left outside the range of chemoattractive signals from the gonad. At E10.5, movie analysis has shown that germ cells remaining in the midline no longer migrate directionally towards the genital ridges, but instead rapidly fragment and disappear. Extragonadal germ cell tumors of infancy, one of the most common neonatal tumors, are thought to arise from midline germ cells that failed to die. This paper addresses the mechanism of midline germ cell death in the mouse. We show that at E10.5, the rate of apoptosis is nearly four-times higher in midline germ cells than those more laterally. Gene expression profiling of purified germ cells suggests this is caused by activation of the intrinsic apoptotic pathway. We then show that germ cell apoptosis in the midline is activated by down-regulation of Steel factor (kit ligand) expression in the midline between E9.5 and E10.5. This is confirmed by the fact that removal of the intrinsic pro-apoptotic protein Bax rescues the germ-cell apoptosis seen in Steel null embryos. Two interesting things are revealed by this: first, germ-cell proliferation does not take place in these embryos after E9.0; second, migration of germ cells is highly abnormal. These data show first that changing expression of Steel factor is required for normal midline germ cell death, and second, that Steel factor is required for normal proliferation and migration of germ cells. PMID:17107997

  2. Applying “Gold Standards” to In vitro-Derived Germ Cells

    PubMed Central

    Handel, Mary Ann; Eppig, John J.; Schimenti, John C.

    2015-01-01

    Germ cells are the ultimate stem cells and reports of their in vitro derivation generate excitement due to potential applications in reproductive medicine. To date there is no firm evidence that meiosis, the hallmark of gametogenesis, can be faithfully replicated outside the gonad. We propose benchmarks for evaluating in vitro derivation of germ cells, facilitating realization of their potential. PMID:24906145

  3. nanos function is essential for development and regeneration of planarian germ cells.

    PubMed

    Wang, Yuying; Zayas, Ricardo M; Guo, Tingxia; Newmark, Phillip A

    2007-04-01

    Germ cells are required for the successful propagation of sexually reproducing species. Understanding the mechanisms by which these cells are specified and how their totipotency is established and maintained has important biomedical and evolutionary implications. Freshwater planarians serve as fascinating models for studying these questions. They can regenerate germ cells from fragments of adult tissues that lack reproductive structures, suggesting that inductive signaling is involved in planarian germ cell specification. To study the development and regeneration of planarian germ cells, we have functionally characterized an ortholog of nanos, a gene required for germ cell development in diverse organisms, from Schmidtea mediterranea. In the hermaphroditic strain of this species, Smed-nanos mRNA is detected in developing, regenerating, and mature ovaries and testes. However, it is not detected in the vast majority of newly hatched planarians or in small tissue fragments that will ultimately regenerate germ cells, consistent with an epigenetic origin of germ cells. We show that Smed-nanos RNA interference (RNAi) results in failure to develop, regenerate, or maintain gonads in sexual planarians. Unexpectedly, Smed-nanos mRNA is also detected in presumptive testes primordia of asexual individuals that reproduce strictly by fission. These presumptive germ cells are lost after Smed-nanos RNAi, suggesting that asexual planarians specify germ cells, but their differentiation is blocked downstream of Smed-nanos function. Our results reveal a conserved function of nanos in germ cell development in planarians and suggest that these animals will serve as useful models for dissecting the molecular basis of epigenetic germ cell specification. PMID:17376870

  4. Control of mammalian germ cell entry into meiosis.

    PubMed

    Feng, Chun-Wei; Bowles, Josephine; Koopman, Peter

    2014-01-25

    Germ cells are unique in undergoing meiosis to generate oocytes and sperm. In mammals, meiosis onset is before birth in females, or at puberty in males, and recent studies have uncovered several regulatory steps involved in initiating meiosis in each sex. Evidence suggests that retinoic acid (RA) induces expression of the critical pre-meiosis gene Stra8 in germ cells of the fetal ovary, pubertal testis and adult testis. In the fetal testis, CYP26B1 degrades RA, while FGF9 further antagonises RA signalling to suppress meiosis. Failsafe mechanisms involving Nanos2 may further suppress meiosis in the fetal testis. Here, we draw together the growing knowledge relating to these meiotic control mechanisms, and present evidence that they are co-ordinately regulated and that additional factors remain to be identified. Understanding this regulatory network will illuminate not only how the foundations of mammalian reproduction are laid, but also how mis-regulation of these steps can result in infertility or germline tumours. PMID:24076097

  5. Extragonadal germ cell tumors are often associated with Klinefelter syndrome.

    PubMed

    Aguirre, David; Nieto, Karem; Lazos, Minerva; Peña, Y Rocio; Palma, Icela; Kofman-Alfaro, Susana; Queipo, Gloria

    2006-04-01

    Klinefelter syndrome is a well documented abnormality of sex differentiation, with an incidence of 1 in 600 newborn males. It is characterized by a 47,XXY or a mosaic karyotype and clinical findings of hypergonadotrophic hypogonadism, small testes, infertility, reduced body hair, gynecomastia, and tall stature. Other conditions like venous disease, autoimmune disorders, mild neurobehavioral deficit, diabetes mellitus, sexual precocity, and osteoporosis may also affect these patients. Different malignancies such as breast cancer, testicular tumors, leukemia, and lymphomas occur in 1%-2% of the cases. Klinefelter syndrome has been associated with other malignancies such as extragonadal germ cell tumors; however, some authors consider this association an unusual finding. We report the molecular cytogenetic studies performed in 4 young males with mediastinal germ cell tumors. In 2 cases, a 47,XXY karyotype was recognized in different tissues by fluorescent in situ hybridization, whereas the other 2 had a normal XY karyotype. We propose that in young patients with mediastinal teratoma, a cytogenetic analysis must always be performed. PMID:16564924

  6. Modeling cell elongation during germ band retraction: cell autonomy versus applied anisotropic stress

    NASA Astrophysics Data System (ADS)

    Lynch, Holley E.; Veldhuis, Jim; Brodland, G. Wayne; Hutson, M. Shane

    2014-05-01

    The morphogenetic process of germ band retraction in Drosophila embryos involves coordinated movements of two epithelial tissues—germ band and amnioserosa. The germ band shortens along its rostral-caudal or head-to-tail axis, widens along its perpendicular dorsal-ventral axis, and uncurls from an initial ‘U’ shape. The amnioserosa mechanically assists this process by pulling on the crook of the U-shaped germ band. The amnioserosa may also provide biochemical signals that drive germ band cells to change shape in a mechanically autonomous fashion. Here, we use a finite-element model to investigate how these two contributions reshape the germ band. We do so by modeling the response to laser-induced wounds in each of the germ band’s spatially distinct segments (T1-T3, A1-A9) during the middle of retraction when segments T1-A3 form the ventral arm of the ‘U’, A4-A7 form its crook, and A8-A9 complete the dorsal arm. We explore these responses under a range of externally applied stresses and internal anisotropy of cell edge tensions—akin to a planar cell polarity that can drive elongation of cells in a direction parallel to the minimum edge tension—and identify regions of parameter space (edge-tension anisotropy versus stress anisotropy) that best match previous experiments for each germ band segment. All but three germ band segments are best fit when the applied stress anisotropy and the edge-tension anisotropy work against one another—i.e., when the isolated effects would elongate cells in perpendicular directions. Segments in the crook of the germ band (A4-A7) have cells that elongate in the direction of maximum external stress, i.e., external stress anisotropy is dominant. In most other segments, the dominant factor is internal edge-tension anisotropy. These results are consistent with models in which the amnioserosa pulls on the crook of the germ band to mechanically assist retraction. In addition, they suggest a mechanical cue for edge

  7. Systemic mastocytosis in a patient with ovarian germ cell carcinoma and mast cell leukemia

    SciTech Connect

    Sun, G.; Hajianpour, M.J.; Hajianpour, A.K.

    1994-09-01

    We report a 12-year-old female with a history of mixed germ cell carcinoma of the right ovary who developed a generalized skin rash after oophorectomy and chemotherapy. She also presented with periodic episodes of flushing, anemia, tachycardia, shortness of breath, high fever, hepatosplenomegaly, nausea, abdominal cramping with diarrhea, and a papuloerythematous skin rash. There was no evidence of secondary carcinoma. Skin biopsy revealed nonspecific inflammatory cells with negative staining for mast cells. Peripheral blood smear showed an increased number of mast cells, thrombocytopenia and normal white cells count. Bone marrow showed hypercellularity with 38% of the nucleated cells being mast cells. Bone marrow chromosome analysis revealed hyperdiploidy in 30% of the cells: 58-64,XX, +1, +2, +5, +6, +7, +8, +14, +16, +18, +19, +19, +20, +21, +22. She expired two months after the occurrence of systemic mastocytosis. Systemic mastocytosis has been reported in association with hematopoietic disorders and with germ cell tumors. The association between mediastinal germ cell tumors and hematological malignancies has also been observed. To our knowledge, combination of most cell leukemia, systemic mastocytosis, and ovarian germ cell carcinoma has not been observed. It is know that mutations at the locus of either proto-oncogene c-kit receptor or its ligand, mast/stem cell factor (SCF) may impair the development of three stem cell populations: hematopoietic stem cells, germ cells and melanoblasts. There have been also extensive investigations on the expression and modulation of the SCF/c-kit interaction in various malignancies. Further molecular studies in patients with germ cell tumor/hematopoietic malignancy syndrome are required to delineate underlying mechanisms.

  8. AIP1-mediated actin disassembly is required for postnatal germ cell migration and spermatogonial stem cell niche establishment

    PubMed Central

    Xu, J; Wan, P; Wang, M; Zhang, J; Gao, X; Hu, B; Han, J; Chen, L; Sun, K; Wu, J; Wu, X; Huang, X; Chen, J

    2015-01-01

    In mammals, spermatogonial stem cells (SSCs) arise from early germ cells called gonocytes, which are derived from primordial germ cells during embryogenesis and remain quiescent until birth. After birth, these germ cells migrate from the center of testicular cord, through Sertoli cells, and toward the basement membrane to form the SSC pool and establish the SSC niche architecture. However, molecular mechanisms underlying germ cell migration and niche establishment are largely unknown. Here, we show that the actin disassembly factor actin interacting protein 1 (AIP1) is required in both germ cells and Sertoli cells to regulate this process. Germ cell-specific or Sertoli cell-specific deletion of Aip1 gene each led to significant defects in germ cell migration after postnatal day 4 or 5, accompanied by elevated levels of actin filaments (F-actin) in the affected cells. Furthermore, our data demonstrated that interaction between germ cells and Sertoli cells, likely through E-cadherin-mediated cell adhesion, is critical for germ cells' migration toward the basement membrane. At last, Aip1 deletion in Sertoli cells decreased SSC self-renewal, increased spermatogonial differentiation, but did not affect the expression and secretion levels of growth factors, suggesting that the disruption of SSC function results from architectural changes in the postnatal niche. PMID:26181199

  9. The role of sex chromosomes in mammalian germ cell differentiation: can the germ cells carrying X and Y chromosomes differentiate into fertile oocytes?

    PubMed Central

    Taketo, Teruko

    2015-01-01

    The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectively. Hence, in normal mammalian development, male germ cells differentiate in the presence of X and Y chromosomes, and female germ cells do so in the presence of two X chromosomes. However, gonadal sex reversal occurs in humans as well as in other mammalian species, and the resultant XX males and XY females can lead healthy lives, except for a complete or partial loss of fertility. Germ cells carrying an abnormal set of sex chromosomes are efficiently eliminated by multilayered surveillance mechanisms in the testis, and also, though more variably, in the ovary. Studying the molecular basis for sex-specific responses to a set of sex chromosomes during gametogenesis will promote our understanding of meiotic processes contributing to the evolution of sex determining mechanisms. This review discusses the fate of germ cells carrying various sex chromosomal compositions in mouse models, the limitation of which may be overcome by recent successes in the differentiation of functional germ cells from embryonic stem cells under experimental conditions. PMID:25578929

  10. Are There Human Germ-Cell Mutagens? We May Know Soon

    EPA Science Inventory

    The existence of agents that can induce germ-cell mutations in experimental systems has been recognized since 1927 with the discovery of the ability of X-rays to induce such mutations in Drosophila. Since then, various rodent-based assays have been used to identify ~50 germ-cell...

  11. Development of interspecies testicular germ-cell transplantation in flatfish.

    PubMed

    Pacchiarini, Tiziana; Sarasquete, Carmen; Cabrita, Elsa

    2014-06-01

    Interspecific testicular germ cell (TGC) transplantation was investigated in two commercial flatfish species. Testes from donor species (Senegalese sole) were evaluated using classical histological techniques (haematoxylin-eosin staining and haematoxylin-light green-orange G-acid fuchsine staining), in situ hybridisation and immunohistochemical analysis. Both Ssvasa1-2 mRNAs and SsVasa protein allowed the characterisation of TGCs, confirming the usefulness of the vasa gene in the detection of Senegalese sole TGCs. Xenogenic transplants were carried out using TGCs from one-year-old Senegalese sole into turbot larvae. Propidium iodide-SYBR-14 and 4',6'-diamidino-2-phenylindole (DAPI) staining showed that 87.98% of the extracted testicular cells were viable for microinjection and that 15.63% of the total recovered cells were spermatogonia. The vasa gene was characterised in turbot recipients using cDNA cloning. Smvasa mRNA was confirmed as a germ cell-specific molecular marker in this species. Smvasa expression analysis during turbot ontogeny was carried out before Senegalese sole TGC transplants into turbot larvae. Turbot larvae at 18 days after hatching (DAH) proved to be susceptible to manipulation procedures. High survival rates (83.75±15.90-100%) were obtained for turbot larvae at 27, 34 and 42 DAH. These data highlight the huge potential of this species for transplantation studies. Quantitative PCR was employed to detect Senegalese sole vasa mRNAs (Ssvasa1-2) in the recipient turbot larvae. The Ssvasa mRNAs showed a significant increase in relative expression in 42-DAH microinjected larvae three weeks after treatment, showing the proliferation of Senegalese sole spermatogonia in transplanted turbot larvae. PMID:23735683

  12. Murine somatic cell nuclear transfer using reprogrammed donor cells expressing male germ cell-specific genes.

    PubMed

    Kang, Hoin; Park, Jong Im; Roh, Sangho

    2016-01-01

    In vivo-matured mouse oocytes were enucleated, and a single murine embryonic fibroblast (control or reprogrammed by introducing extracts from murine testis tissue, which showed expression of male germ cell-specific genes) was injected into the cytoplasm of the oocytes. The rate of blastocyst development and expression levels of Oct-4, Eomes and Cdx-2 were not significantly different in both experimental groups. However, the expression levels of Nanog, Sox9 and Glut-1 were significantly increased when reprogrammed cells were used as donor nuclei. Increased expression of Nanog can be supportive of complete reprogramming of somatic cell nuclear transfer murine embryos. The present study suggested that donor cells expressing male germ cell-specific genes can be reconstructed and can develop into embryos with normal high expression of developmentally essential genes. PMID:26369430

  13. Bisphenol A exposure inhibits germ cell nest breakdown by reducing apoptosis in cultured neonatal mouse ovaries.

    PubMed

    Zhou, Changqing; Wang, Wei; Peretz, Jackye; Flaws, Jodi A

    2015-11-01

    Bisphenol A is a known endocrine disrupting chemical and reproductive toxicant. Previous studies indicate that in utero BPA exposure increases the percentage of germ cells in nests and decreases the percentage of primordial follicles. However, the mechanism by which BPA affects germ cell nest breakdown is unknown. Thus, we hypothesized that BPA inhibits germ cell nest breakdown by interfering with oxidative stress and apoptosis pathways. To test our hypothesis, ovaries from newborn mice were collected and cultured with vehicle (dimethyl sulfoxide, DMSO) or different doses of BPA (0.1, 1, 5, and 10μg/mL). Ovaries then were subjected to histological evaluation of germ cell nests and primordial follicles or to measurements of factors that regulate oxidative stress and apoptosis. Our results indicate that in vitro BPA exposure significantly inhibits germ cell nest breakdown by altering the expression of key ovarian apoptotic genes, but not by interfering with the oxidative stress pathway. PMID:26049153

  14. Germ cells and ova in dysgenetic gonads of a 46-XY female dizygotic twin.

    PubMed

    Cussen, L J; MacMahon, R A

    1979-04-01

    The frequency of germ cell neoplasms in girls with 46-XY gonadal dysgenesis suggests that germ cells may persist in the dysgenetic gonads for many years. A phenotypic female infant with a karyotype of 46-XY in blood, skin, and gonads had a few ova in primordial follicles and numerous germ cells in her dysgenetic gonads at the age of 3 months. At 3 years and 10 months of age her gonads contained no primordial follicle and the only remaining germ cells were in a gonadoblastoma. We propose that germ cells are lost from dysgenetic gonads much more rapidly than from normal gonads, but that the rate of loss in patients with a karyotype of 46-XY may be less than the rate of loss in patients with a karyotype of 45-XO. PMID:433851

  15. Implications of Sertoli cell induced germ cell apoptosis to testicular pathology

    PubMed Central

    Murphy, Caitlin J; Richburg, John H

    2014-01-01

    After exposure to toxicants, degenerating germ cells represents the most common testicular histopathological alteration, regardless of the mechanism of toxicity. Therefore, deciphering the primary toxicant cellular target and mechanism of action can be extremely difficult. However, most testicular toxicants display a cell-specific and a stage-specific pattern of damage, which is the best evidence for identifying the primary cellular target (i.e. germ cell, Sertoli cell, peritubular myoid cell, or Leydig cell). Some toxicant-induced Sertoli cell injury presents with germ cell apoptosis occurring primarily in spermatocytes in rats in stages XI-XIV, I and II. Although some toxicants result in spermatid degeneration and apoptosis, it is still unclear if spermatid apoptosis is a result of Sertoli cell-selective apoptosis or a direct effect of toxicants on spermatids, therefore if this is seen as the earliest change, one cannot infer the mechanism of apoptosis. This review summarizes some of the distinguishing features of Sertoli cell-induced germ cell apoptosis and the associated mechanisms of cell death to provide the toxicologist observing similar cell death, with evidence about a potential mode of action. PMID:26413394

  16. In vivo analysis of germ cell apoptosis reveals the existence of stage-specific 'social' control of germ cell death in the seminiferous epithelium.

    PubMed

    Blanco-Rodríguez, J; Martínez-García, C

    1997-12-01

    It has become clear in recent years that programmed cell death is regulated during development by signals from other cells. Nevertheless, compared to the 'social' control of cell proliferation, relatively little is known about the 'social' control of cell death in other systems. Since in a previous study we showed that induced germ cell apoptosis occurs at specific stages of the spermatogenic cycle, in this study we aimed to ascertain the existence of supracellular control of germ cell death during spermatogenesis. Therefore, the TUNEL technique has been used to analyse whether all of the different germ cell types are induced to die at these specific stages in animals injected intratesticularly with one of several inducers of apoptosis. Our findings suggest that all of the investigated agents trigger apoptosis in all the diverse progenies of germ cells existing at stages I, XII or XIV of the spermatogenic cycle. In contrast, at most other stages the number of apoptotic cells was similar to that found in control animals. These data are consistent with the existence of an intercellular control of germ cell death during spermatogenesis. We conclude that the seminiferous epithelium provides a suitable in vivo model to study the mechanisms underlying the 'social' control of apoptosis. PMID:9568531

  17. Pediatric Germ Cell Tumors; A 10-year Experience

    PubMed Central

    Khaleghnejad-Tabari, Ahmad; Mirshemirani, Alireza; Rouzrokh, Mohsen; Mohajerzadeh, Leily; Khaleghnejad-Tabari, Nasibeh; Hasas-Yeganeh, Shaghayegh

    2014-01-01

    Objective: The aim of this study was to evaluate the outcome of germ cell tumors in patients admitted to our center during a ten year period. Methods: In a retrospective descriptive study, patients with the pathological diagnosis of germ cell tumor (GCT) were included. All records were evaluated and patients followed by personal visit in clinic or phone call. Data regarding age, sex, tumor site, bio-chemical assay, pathology, treatment and outcomes were gathered. For qualitative variables we computed frequency and percentage and for quantitative variables, mean and standard deviation. Survival analysis was performed using Kaplan-Meier. All statistical analyses were performed by SPSS version16.0. Findings : Forty four patients consisted of 32 girls (72.7%) and 12 boys (27.3%). Their median age was 23 months. The most common pathological tumor types were 18 (40.9%) mature teratomas and 14 (31.8%) yolk sac tumors. Extra gonadal tumors were more prevalent (32 cases) and consisted of 21 (47.7%) sacrcoccygeal, 7 (15.9%) retroperitoneal, 2 (4.4%) mediastinal and 2 (4.4%) cervical tumors. In gonadal tumors 9 patients had ovarian and 3 patients testicular involvement. Staging at the time of diagnosis revealed stage one in 23 (52.3%) cases. All patients were treated surgically and the most common procedure was total resection in 41 (93.2%) patients. Fifteen (34.1%) patients received chemotherapy. In follow-up 31 (77.5%) patients were in complete remission, 9 (22.5%) had died, and 4 cases did not appear to follow-up visits. The median survival was 16 months (IQR 4-49 months). The highest mortality rate was found in patients with yolk sac tumors (8 of 13 cases). Conclusion: The patients with extra-gonadal GCT and a high AFP level have the worst prognosis and lower survival rate. Combination of surgery and chemotherapy can lead to a better prognosis. PMID:25755868

  18. Melphalan, Carboplatin, Mannitol, and Sodium Thiosulfate in Treating Patients With Recurrent or Progressive CNS Embryonal or Germ Cell Tumors

    ClinicalTrials.gov

    2016-04-28

    Adult Central Nervous System Germ Cell Tumor; Adult Ependymoblastoma; Adult Medulloblastoma; Adult Pineoblastoma; Adult Supratentorial Primitive Neuroectodermal Tumor; Childhood Atypical Teratoid/Rhabdoid Tumor; Childhood Central Nervous System Germ Cell Tumor; Childhood Ependymoblastoma; Medulloepithelioma; Ototoxicity; Recurrent Adult Brain Neoplasm; Recurrent Childhood Central Nervous System Embryonal Neoplasm; Recurrent Childhood Malignant Germ Cell Tumor; Recurrent Childhood Medulloblastoma; Recurrent Childhood Pineoblastoma; Recurrent Childhood Supratentorial Primitive Neuroectodermal Tumor

  19. Mechano-logical model of C. elegans germ line suggests feedback on the cell cycle

    PubMed Central

    Atwell, Kathryn; Qin, Zhao; Gavaghan, David; Kugler, Hillel; Hubbard, E. Jane Albert; Osborne, James M.

    2015-01-01

    The Caenorhabditis elegans germ line is an outstanding model system in which to study the control of cell division and differentiation. Although many of the molecules that regulate germ cell proliferation and fate decisions have been identified, how these signals interact with cellular dynamics and physical forces within the gonad remains poorly understood. We therefore developed a dynamic, 3D in silico model of the C. elegans germ line, incorporating both the mechanical interactions between cells and the decision-making processes within cells. Our model successfully reproduces key features of the germ line during development and adulthood, including a reasonable ovulation rate, correct sperm count, and appropriate organization of the germ line into stably maintained zones. The model highlights a previously overlooked way in which germ cell pressure may influence gonadogenesis, and also predicts that adult germ cells might be subject to mechanical feedback on the cell cycle akin to contact inhibition. We provide experimental data consistent with the latter hypothesis. Finally, we present cell trajectories and ancestry recorded over the course of a simulation. The novel approaches and software described here link mechanics and cellular decision-making, and are applicable to modeling other developmental and stem cell systems. PMID:26428008

  20. Testicular structure and germ cells morphology in salamanders

    PubMed Central

    Uribe, Mari Carmen; Mejía-Roa, Víctor

    2014-01-01

    Testes of salamanders or urodeles are paired elongated organs that are attached to the dorsal wall of the body by a mesorchium. The testes are composed of one or several lobes. Each lobe is morphologically and functionally a similar testicular unit. The lobes of the testis are joined by cords covered by a single peritoneal epithelium and subjacent connective tissue. The cords contain spermatogonia. Spermatogonia associate with Sertoli cells to form spermatocysts or cysts. The spermatogenic cells in a cyst undergo their development through spermatogenesis synchronously. The distribution of cysts displays the cephalo-caudal gradient in respect to the stage of spermatogenesis. The formation of cysts at cephalic end of the testis causes their migration along the lobules to the caudal end. Consequently, the disposition in cephalo-caudal regions of spermatogenesis can be observed in longitudinal sections of the testis. The germ cells are spermatogonia, diploid cells with mitotic activity; primary and second spermatocytes characterized by meiotic divisions that develop haploid spermatids; during spermiogenesis the spermatids differentiate to spermatozoa. During spermiation the cysts open and spermatozoa leave the testicular lobules. After spermiation occurs the development of Leydig cells into glandular tissue. This glandular tissue regressed at the end of the reproductive cycle. PMID:26413406

  1. SYNAPTONEMAL COMPLEX DAMAGE AS A MEASURE OF CHEMICAL MUTAGEN EFFECTS ON MAMMALIAN GERM CELLS

    EPA Science Inventory

    As heritable chromosome anomalies are implicated in a variety of human disabilities, their induction in germ cells by environmental chemicals is viewed as a threat to health. Synaptonemal complex (SC) analysis is a novel approach for the detection of germ-line chromosomal damage....

  2. Control over the morphology and segregation of Zebrafish germ cell granules during embryonic development

    PubMed Central

    Strasser, Markus J; Mackenzie, Natalia C; Dumstrei, Karin; Nakkrasae, La-Iad; Stebler, Jürg; Raz, Erez

    2008-01-01

    Background Zebrafish germ cells contain granular-like structures, organized around the cell nucleus. These structures share common features with polar granules in Drosophila, germinal granules in Xenopus and chromatoid bodies in mice germ cells, such as the localization of the zebrafish Vasa, Piwi and Nanos proteins, among others. Little is known about the structure of these granules as well as their segregation in mitosis during early germ-cell development. Results Using transgenic fish expressing a fluorescently labeled novel component of Zebrafish germ cell granules termed Granulito, we followed the morphology and distribution of the granules. We show that whereas these granules initially exhibit a wide size variation, by the end of the first day of development they become a homogeneous population of medium size granules. We investigated this resizing event and demonstrated the role of microtubules and the minus-end microtubule dependent motor protein Dynein in the process. Last, we show that the function of the germ cell granule resident protein the Tudor domain containing protein-7 (Tdrd7) is required for determination of granule morphology and number. Conclusion Our results suggest that Zebrafish germ cell granules undergo a transformation process, which involves germ cell specific proteins as well as the microtubular network. PMID:18507824

  3. Vasculogenesis and angiogenesis in nonseminomatous testicular germ cell tumors.

    PubMed

    Silván, Unai; Díez-Torre, Alejandro; Bonilla, Zuriñe; Moreno, Pablo; Díaz-Núñez, María; Aréchaga, Juan

    2015-06-01

    Testicular germ cell tumors (TGCTs) comprise the vast majority of all testicular malignancies and are the most common type of cancer among young male adults. The nonseminomatous variant of TGCTs is characterized by the presence of embryonic and extraembryonic tissues together with a population of pluripotent cancer stem cells, the so-called embryonal carcinoma. One of the main causes of the resistance of these tumors to therapy is their ability to invade adjacent tissues and metastasize into distant sites of the body. Both of these tumor processes are highly favored by the neovascularization of the malignant tissue. New vessels can be generated by means of angiogenesis or vasculogenesis, and both have been observed to occur during tumor vascularization. Nevertheless, the precise contribution of each process to the neoplastic vascular bed of TGCTs remains unknown. In addition, another process known as tumor-derived vasculogenesis, in which malignant cells give rise to endothelial cells, has also been reported to occur in a number of tumor types, including experimental TGCTs. The participation and cross talk of these 3 processes in tumor vascularization is of particular interest, given the embryonic origin of teratocarcinomas. Thus, in the present review, we discuss the importance of all 3 vascularization processes in the growth, invasion, and metastasis of testicular teratocarcinomas and summarize the current state of knowledge of the TGCT microenvironment and its relationship with vascularization. Finally, we discuss the importance of vascularization as a therapeutic target for this type of malignancy. PMID:25772688

  4. Differentiation of early germ cells from human skin-derived stem cells without exogenous gene integration.

    PubMed

    Ge, Wei; Ma, Hua-Gang; Cheng, Shun-Feng; Sun, Yuan-Chao; Sun, Li-Lan; Sun, Xiao-Feng; Li, Lan; Dyce, Paul; Li, Julang; Shi, Qing-Hua; Shen, Wei

    2015-01-01

    Infertility has long been a difficult issue for many couples. The successful differentiation of germ cells and live progeny from pluripotent stem cells brings new hope to the couples suffering with infertility. Here we successfully isolated human fetus skin-derived stem cells (hfSDSCs) from fetus skin tissue and demonstrated that hfSDSCs can be differentiated into early human germ cell-like cells (hGCLCs). These cells express human germ cell markers DAZL and VASA. Moreover, these pluripotent stem cell-derived hGCLCs are free of exogenous gene integration. When hfSDSCs were differentiated in porcine follicle fluid (PFF) conditioned media, which has been shown to promote the differentiation of mouse and porcine SDSCs into oocyte-like cells (OLCs), we observed some vesicular structures formed from hfSDSCs. Moreover, when hfSDSCs were cultured with specific conditioned media, we observed punctate and elongated SCP3 staining foci, indicating the initiation of meiosis. Ploidy analysis and fluorescent in situ hybridization (FISH) analysis indicated that a small percentage of putative 1N populations formed from hfSDSCs when compared with positive controls. In conclusion, our data here, for the first time, demonstrated that hfSDSCs possess the differentiation potential into germ lines, and they may differentiate both male and female hGCLCs in vitro under appropriate conditions. PMID:26347377

  5. Ovarian malignant mixed germ cell tumor with clear cell carcinoma in a postmenopausal woman

    PubMed Central

    Yu, Xiu-Jie; Zhang, Lin; Liu, Zai-Ping; Shi, Yi-Quan; Liu, Yi-Xin

    2014-01-01

    Malignant germ cell tumors of the ovary are very rare and account for about 2-5% of all ovarian tumors of germ origin. Most patients are adolescent and young women, approximately two-thirds of them are under 20 years of age, occasionally in postmenopausal women. But clear cell carcinoma usually occurs in older patients (median age: 57-year old), and closely related with endometriosis. Here we report a case of a 55-year old woman with right ovarian mass that discovered by B ultrasonic. Her serum levels of human chorionic gonadotropin (hCG) and α-fetoprotein (AFP) were elevated. Pathological examination revealed the tumor to be a mixed germ cell tumor (yolk sac tumor, embryonal carcinoma and mature teratoma) with clear cell carcinoma in a background of endometriosis. Immunohistochemical staining showed SALL4 and PLAP were positive in germ cell tumor area, hCG, CD30 and OCT4 were positive in epithelial-like cells and giant synctiotrophoblastic cells, AFP, AAT, CD117 and Glyp3 were positive in yolk sac component, EMA and CK7 were positive in clear cell carcinoma, CD10 was positive in endometrial cells of endometriotic area. She was treated with surgery followed by seven courses of chemotherapy. She is well and serum levels of hCG and AFP have been decreased to normal levels. PMID:25674278

  6. Ovarian malignant mixed germ cell tumor with clear cell carcinoma in a postmenopausal woman.

    PubMed

    Yu, Xiu-Jie; Zhang, Lin; Liu, Zai-Ping; Shi, Yi-Quan; Liu, Yi-Xin

    2014-01-01

    Malignant germ cell tumors of the ovary are very rare and account for about 2-5% of all ovarian tumors of germ origin. Most patients are adolescent and young women, approximately two-thirds of them are under 20 years of age, occasionally in postmenopausal women. But clear cell carcinoma usually occurs in older patients (median age: 57-year old), and closely related with endometriosis. Here we report a case of a 55-year old woman with right ovarian mass that discovered by B ultrasonic. Her serum levels of human chorionic gonadotropin (hCG) and α-fetoprotein (AFP) were elevated. Pathological examination revealed the tumor to be a mixed germ cell tumor (yolk sac tumor, embryonal carcinoma and mature teratoma) with clear cell carcinoma in a background of endometriosis. Immunohistochemical staining showed SALL4 and PLAP were positive in germ cell tumor area, hCG, CD30 and OCT4 were positive in epithelial-like cells and giant synctiotrophoblastic cells, AFP, AAT, CD117 and Glyp3 were positive in yolk sac component, EMA and CK7 were positive in clear cell carcinoma, CD10 was positive in endometrial cells of endometriotic area. She was treated with surgery followed by seven courses of chemotherapy. She is well and serum levels of hCG and AFP have been decreased to normal levels. PMID:25674278

  7. The fog-3 gene and regulation of cell fate in the germ line of Caenorhabditis elegans

    SciTech Connect

    Ellis, R.; Kimble, J.

    1995-02-01

    In the nematode Caenorhabditis elegans, germ cells normally adopt one of three fates: mitosis, spermatogenesis or oogenesis. We have identified and characterized the gene fog-3, which is required for germ cells to differentiate as sperm rather than as oocytes. Analysis of double mutants suggests that fog-3 is absolutely required for spermatogenesis and acts at the end of the regulatory hierarchy controlling sex determination for the germ line. By contrast, mutations in fog-3 do not alter the sexual identity of other tissues. We also have characterized the null phenotype of fog-1, another gene required for spermatogenesis; we demonstrate that it too controls the sexual identity of germ cells but not of other tissues. Finally, we have studied the same interaction of these two fog genes with gld-1, a gene required for germ cells to undergo oogenesis rather than mitosis. On the basis of these results, we propose that germ-cell fate might be controlled by a set of inhibitory interactions among genes that specify one of three fates: mitosis, spermatogenesis or oogenesis. Such a regulatory network would link the adoption of one germ-cell fate to the suppression of the other two. 68 refs., 7 figs., 6 tabs.

  8. Chemotherapy for Good-Risk Nonseminomatous Germ Cell Tumors: Current Concepts and Controversies.

    PubMed

    In, Gino; Dorff, Tanya

    2015-08-01

    The rate of diagnosis of germ cell tumors has remained fairly constant. By the International Germ Cell Cancer Consensus Classification, roughly 60% of all metastatic germ cell tumors are classified as good risk. This group of patients has an excellent prognosis, with greater than 90% expectation of cure. Treatment standards have not changed much in recent years. This article focuses on key concepts in the development of the currently accepted first-line regimens and addresses some evolving areas of interest, if not controversy. PMID:26216822

  9. Germ cells are essential for sexual dimorphism in the medaka gonad

    PubMed Central

    Kurokawa, Hiromi; Saito, Daisuke; Nakamura, Shuhei; Katoh-Fukui, Yuko; Ohta, Kohei; Baba, Takashi; Morohashi, Ken-ichiro; Tanaka, Minoru

    2007-01-01

    To further elucidate the roles of germ cells in the sex differentiation of gonads, we have used the medaka, a teleost fish, to generate mutants that lack germ cells from the onset of gonadogenesis by the morpholino-mediated knockdown of cxcr4. The resulting germ-cell-deficient medaka show female-to-male sex reversal of their secondary sex characteristics, accompanied by increased levels of androgen and reduced levels of estrogen. A failure to maintain granulosa cells or estrogen-producing cells also occurs at early stages of sex differentiation in the cxcr4 morphants, before the initiation of gonadal morphogenesis. In contrast, androgen-producing cells are unaffected in germ-cell-deficient medaka of either sex. In addition, a single tube-like gonad that expresses male-specific genes is formed in these mutants irrespective of the genetic sex. Significantly, each of these mutant phenotypes occurs in a somatic cell-autonomous manner, suggesting that gonadal somatic cells are predisposed toward male development in the absence of germ cells. This highlights the importance of germ cells in the sexual dimorphism of the gonads. PMID:17940041

  10. Mouse oocytes differentiate through organelle enrichment from sister cyst germ cells.

    PubMed

    Lei, Lei; Spradling, Allan C

    2016-04-01

    Oocytes differentiate in diverse species by receiving organelles and cytoplasm from sister germ cells while joined in germline cysts or syncytia. Mouse primordial germ cells form germline cysts, but the role of cysts in oogenesis is unknown. We find that mouse germ cells receive organelles from neighboring cyst cells and build a Balbiani body to become oocytes, whereas nurselike germ cells die. Organelle movement, Balbiani body formation, and oocyte fate determination are selectively blocked by low levels of microtubule-dependent transport inhibitors. Membrane breakdown within the cyst and an apoptosis-like process are associated with organelle transfer into the oocyte, events reminiscent of nurse cell dumping in Drosophila We propose that cytoplasmic and organelle transport plays an evolutionarily conserved and functionally important role in mammalian oocyte differentiation. PMID:26917595