scholarly journals The H3K9 methyltransferase SETDB1 maintains female identity in Drosophila germ cells by repressing expression of key spermatogenesis genes

2018 ◽  
Author(s):  
Anne E. Smolko ◽  
Laura Shapiro-Kulnane ◽  
Helen K. Salz
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Target Genes ◽  
Female Identity ◽  
Binding Partner ◽  
Regional Deposition ◽  
Female Specific ◽  
Inappropriate Expression ◽  
Novel Model

AbstractThe preservation of germ cell sexual identity is essential for gametogenesis. Here we show that H3K9me3-mediated gene silencing is integral to female fate maintenance in Drosophila germ cells. Germ cell-specific loss of the H3K9me3 pathway members, the trimethyltransferase SETDB1, its binding partner WDE, and the H3K9 binding protein HP1a, cause the inappropriate expression of testis genes. SETDB1 is required for H3K9me3 accumulation on a select subset of the silenced testis genes. Interestingly, these SETDB1-dependent H3K9me3 domains are highly localized and do not spread into neighboring loci. Regional deposition is especially striking at the phf7 locus, a key regulator of male germ cell sexual fate. phf7 is primarily regulated by alternative promoter usage and transcription start site (TSS) selection. We find H3K9me3 accumulation is restricted to the silenced testis-specific TSS region in ovaries. Furthermore, its recruitment to phf7 and repression of the testis-specific transcript is dependent on the female sex determination gene Sxl. These findings demonstrate that female identity is secured by a pathway in which Sxl is the upstream female-specific regulator, SETDB1 is the required chromatin writer and phf7 is one of the critical SETDB1 target genes. This function of SETDB1 is unrelated to its canonical role in piRNA biogenesis and silencing of transposable elements. Collectively our findings support a novel model in which female fate is preserved by deposition of H3K9me3 repressive marks on key spermatogenesis genes and suggest that this strategy for securing cell fate may be widespread.

scholarly journals Genetic control of programmed cell death in the Caenorhabditis elegans hermaphrodite germline

Development ◽  
1999 ◽  
Vol 126 (5) ◽  
pp. 1011-1022 ◽  
Author(s):  
T.L. Gumienny ◽  
E. Lambie ◽  
E. Hartwieg ◽  
H.R. Horvitz ◽  
M.O. Hengartner
Keyword(s):  
Cell Death ◽  
Caenorhabditis Elegans ◽  
Germ Cell ◽  
Somatic Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Mapk Pathway ◽  
Apoptotic Cell ◽  
C Elegans ◽  
Pathway Activation

Development of the nematode Caenorhabditis elegans is highly reproducible and the fate of every somatic cell has been reported. We describe here a previously uncharacterized cell fate in C. elegans: we show that germ cells, which in hermaphrodites can differentiate into sperm and oocytes, also undergo apoptotic cell death. In adult hermaphrodites, over 300 germ cells die, using the same apoptotic execution machinery (ced-3, ced-4 and ced-9) as the previously described 131 somatic cell deaths. However, this machinery is activated by a distinct pathway, as loss of egl-1 function, which inhibits somatic cell death, does not affect germ cell apoptosis. Germ cell death requires ras/MAPK pathway activation and is used to maintain germline homeostasis. We suggest that apoptosis eliminates excess germ cells that acted as nurse cells to provide cytoplasmic components to maturing oocytes.

scholarly journals Phase Transitioned Nuclear Oskar Promotes Cell Division of Drosophila Primordial Germ Cells

2018 ◽  
Author(s):  
Kathryn E. Kistler ◽  
Tatjana Trcek ◽  
Thomas R. Hurd ◽  
Ruoyu Chen ◽  
Feng-Xia Liang ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Cell Function ◽  
Primordial Germ Cells ◽  
Nuclear Localization Sequence ◽  
Cell Systems ◽  
Germ Granules ◽  
Localization Sequence ◽  
Transcriptional Gene Regulation

ABSTRACTGerm granules are non-membranous ribonucleoprotein granules deemed the hubs for post-transcriptional gene regulation and functionally linked to germ cell fate across species. Little is known about the physical properties of germ granules and how these relate to germ cell function. Here we study two types of germ granules in the Drosophila embryo: cytoplasmic germ granules that instruct primordial germ cells (PGCs) formation and nuclear germ granules within early PGCs with unknown function. We show that cytoplasmic and nuclear germ granules are phase transitioned condensates nucleated by Oskar protein that display liquid as well as hydrogel-like properties. Focusing on nuclear granules, we find that Oskar drives their formation in heterologous cell systems. Multiple, independent Oskar protein domains synergize to promote granule phase separation. Deletion of Oskar’s nuclear localization sequence specifically ablates nuclear granules in cell systems. In the embryo, nuclear germ granules promote germ cell divisions thereby increasing PGC number for the next generation.

scholarly journals Germ cell fate and seminiferous tubule development in bovine testis xenografts

Reproduction ◽  
2005 ◽  
Vol 130 (6) ◽  
pp. 923-929 ◽  
Author(s):  
Rahul Rathi ◽  
Ali Honaramooz ◽  
Wenxian Zeng ◽  
Stefan Schlatt ◽  
Ina Dobrinski
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Cell Number ◽  
Sperm Production ◽  
Continuous Increase ◽  
Control Tissue ◽  
Low Efficiency ◽  
Pachytene Spermatocytes ◽  
Testis Tissue

Spermatogenesis can occur in testis tissue from immature bulls ectopically grafted into mouse hosts; however, efficiency of sperm production is lower than in other donor species. To elucidate a possible mechanism for the impaired spermatogenesis in bovine testis xenografts, germ cell fate and xenograft development were investigated at different time points and compared with testis tissue from age-matched calves as controls. Histologically, an initial decrease in germ cell number was noticed in xenografts recovered up to 2 months post-grafting without an increase in germ cell apoptosis. From 2 months onward, the number of germ cells increased. In contrast, a continuous increase in germ cell number was seen in control tissue. Pachytene spermatocytes were observed in some grafts before 4 months, whereas in the control tissue they were not present until 5 months of age. Beyond 4 months post-grafting spermatogenesis appeared to be arrested at the pachytene spermatocyte stage in most grafts. Elongated spermatids were observed between 6 and 8 months post-grafting, similar to the controls, albeit in much lower numbers. Lumen formation started earlier in grafts compared with controls and by 6 months post-grafting tubules with extensively dilated lumen were observed. A donor effect on efficiency of spermatogenesis was also observed. These results indicate that the low efficiency of sperm production in bovine xenografts is due to an initial deficit of germ cells and impaired meiotic and post-meiotic differentiation. The characterization of spermatogenic efficiency will provide the basis to understand the control of spermatogenesis in testis grafts.

scholarly journals Differential developmental expression of transcription factors GATA-4 and GATA-6, their cofactor FOG-2 and downstream target genes in testicular carcinoma in situ and germ cell tumors

2010 ◽  
Vol 162 (3) ◽  
pp. 625-631 ◽  
Author(s):  
Jonna Salonen ◽  
Ewa Rajpert-De Meyts ◽  
Susanna Mannisto ◽  
John E Nielsen ◽  
Niels Graem ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Germ Cell ◽  
Germ Cells ◽  
Target Genes ◽  
Developmental Expression ◽  
Human Testis ◽  
Testicular Development ◽  
Downstream Target ◽  
Germ Cell Differentiation

ObjectiveTesticular germ cell cancer is the most common malignancy among young males. The pre-invasive precursor, carcinoma in situ testis (CIS), presumably originates from arrested and transformed fetal gonocytes. Given that GATA transcription factors have essential roles in embryonic and testicular development, we explored the expression of GATA-4, GATA-6, cofactor friend of GATA (FOG)-2, and downstream target genes during human testis development and addressed the question whether changes in this pathway may contribute to germ cell neoplasms.MethodsFetal testis, testicular CIS, and overt tumor samples were analyzed by immunohistochemistry for GATA-4, GATA-6, FOG-2, steroidogenic factor 1 (NR5A1/SF1), anti-Müllerian hormone/Müllerian-inhibiting substance (AMH), and inhibin-α (INHα).ResultsGATA-4 was not expressed in normal germ cells, except for a subset of gonocytes at the 15th gestational week. The CIS cells expressed GATA-4 and GATA-6 heterogeneously, whereas most of the CIS cells expressed GATA-4 cofactor FOG-2. GATA target gene SF-1 was expressed heterogeneously in CIS cells, whereas INHα and AMH were mostly negative. Seminomas and yolk sac tumors were positive for GATA-4 and GATA-6, but mostly negative for FOG-2 and the GATA target genes. In contrast, pluripotent embryonal carcinomas and choriocarcinomas were GATA-4 and GATA-6 negative.ConclusionsDifferential expression of the GATA-4 target genes suggested cell-specific functions of GATA-4 in the germ and somatic cells. The GATA-4 expression in early fetal gonocytes, CIS, and seminoma cells but the absence in more mature germ cells is consistent with the early fetal origin of CIS cells and suggests that GATA-4 is involved in early germ cell differentiation.

scholarly journals Analysis of lncRNA Expression Profile during the Formation of Male Germ Cells in Chickens

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1850
Author(s):  
Wen Gao ◽  
Chen Zhang ◽  
Kai Jin ◽  
Yani Zhang ◽  
Qisheng Zuo ◽  
...  
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Signaling Pathways ◽  
Germ Cells ◽  
Target Genes ◽  
Cell Formation ◽  
Cell Development ◽  
Germ Cell Development ◽  
Germ Cell Differentiation ◽  
Germ Cell Formation

Germ cells have an irreplaceable role in transmitting genetic information from one generation to the next, and also play an important role in sex differentiation in poultry, while little is known about epigenetic factors that regulate germ cell differentiation. In this study, RNA-seq was used to detect the expression profiles of long non-coding RNAs (lncRNAs) during the differentiation of chicken embryonic stem cells (ESCs) into spermatogonial stem cells (SSCs). The results showed that a total of 296, 280 and 357 differentially expressed lncRNAs (DELs) were screened in ESCs vs. PGCs, ESCs vs. SSCs and PGCs vs. SSCs, respectively. Gene Ontology (GO) and KEGG enrichment analysis showed that DELs in the three cell groups were mainly enriched in autophagy, Wnt/β-catenin, TGF-β, Notch and ErbB and signaling pathways. The co-expression network of 37 candidate DELs and their target genes enriched in the biological function of germ cell development showed that XLOC_612026, XLOC_612029, XLOC_240662, XLOC_362463, XLOC_023952, XLOC_674549, XLOC_160716, ALDBGALG0000001810, ALDBGALG0000002986, XLOC_657380674549, XLOC_022100 and XLOC_657380 were the key lncRNAs in the process of male germ cell formation and, moreover, the function of these DELs may be related to the interaction of their target genes. Our findings preliminarily excavated the key lncRNAs and signaling pathways in the process of male chicken germ cell formation, which could be helpful to construct the gene regulatory network of germ cell development, and also provide new ideas for further optimizing the induction efficiency of germ cells in vitro.

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

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 561-577 ◽  
Author(s):  
R E Ellis ◽  
J Kimble
Keyword(s):  
Caenorhabditis Elegans ◽  
Germ Cell ◽  
Sexual Identity ◽  
Cell Fate ◽  
Germ Cells ◽  
Regulatory Network ◽  
Germ Line ◽  
The Other ◽  
Nematode Caenorhabditis Elegans ◽  
Inhibitory Interactions

Abstract 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 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.

scholarly journals Nodal Signaling Regulates the Entry into Meiosis in Fetal Germ Cells

Endocrinology ◽  
2012 ◽  
Vol 153 (5) ◽  
pp. 2466-2473 ◽  
Author(s):  
Benoit Souquet ◽  
Sophie Tourpin ◽  
Sébastien Messiaen ◽  
Delphine Moison ◽  
René Habert ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Target Genes ◽  
Normal Male ◽  
Nodal Signaling ◽  
Male Germ Cells ◽  
Embryonic Germ Cells ◽  
Meiotic Inhibitors ◽  
First Time

The mechanisms regulating the entry into meiosis in mammalian germ cells remain incompletely understood. We investigated the involvement of the TGF-β family members in fetal germ cell meiosis initiation. Nodal, a member of the TGF-β family, and its target genes are precociously expressed in embryonic gonads and show sexual dimorphism in favor of the developing testis. Nodal receptor genes, Acvr2a and Acvr2b, Alk4, and Tdgf1/Cripto, were identified in male germ cells. Nodal itself, Tdgf1, and Lefty1 and Lefty2 are targets of Nodal signaling and were all found specifically expressed in male germ cells. To elucidate the role of this signaling pathway, activin-like kinases that mediate TGF-β/Nodal/activin signaling were inhibited in 11.5 d postconception testis in organotypic culture. Activin-like kinases inhibition disrupted normal male germ cell development and induced germ cell entry into meiosis such as that observed in female germ cells at the equivalent stage. Interestingly Stra8, the gatekeeper of the mitotic/meiotic switch, was induced independently of any change of either Cyp26b1 or Fgf9 expression, the two genes currently identified as testicular meiotic inhibitors. On the other hand, recombinant Nodal significantly dampened Stra8 expression and germ cell meiosis in cultured 11.5 d postconception ovaries. Our results allowed us to propose for the first time an autocrine role of Nodal during the development of germ cells and indicate that members of the TGB-β family may reinforce the male fate and prevent meiosis in embryonic germ cells.

scholarly journals Germline sexual fate is determined by the antagonistic action of dmrt1 and foxl3/foxl2 in tilapia

Development ◽  
2021 ◽  
pp. dev.199380
Author(s):  
Shengfei Dai ◽  
Shuangshuang Qi ◽  
Xueyan Wei ◽  
Xingyong Liu ◽  
Yibing Li ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Germ Cell ◽  
Somatic Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Sex Reversal ◽  
Testicular Development ◽  
Antagonistic Action ◽  
Male And Female ◽  
Fate Decision

Germline sexual fate has long been believed to be determined by the somatic environment, but this idea is challenged by recent studies of foxl3 mutants in medaka. Here we demonstrate that the sexual fate of tilapia germline is determined by the antagonistic interaction of dmrt1 and foxl3, which are transcriptionally repressed in male and female germ cells, respectively. Loss of dmrt1 rescued the germ cell sex reversal in foxl3Δ7/Δ7 XX fish, and loss of foxl3 partially rescued germ cell sex reversal but not somatic cell fate in dmrt1Δ5/Δ5 XY fish. Interestingly, germ cells lost sexual plasticity in dmrt1Δ5/Δ5 XY and foxl3Δ7/Δ7 XX single mutants, as aromatase inhibitor and estrogen treatment failed to rescue the respective phenotypes. However, recovery of germ cell sexual plasticity was observed in dmrt1/foxl3 double mutants. Importantly, mutation of somatic cell specific foxl2 resulted in testicular development in foxl3Δ7/Δ7 or dmrt1Δ5/Δ5 mutants. Our findings demonstrate that sexual plasticity of germ cells relies on the presence of both dmrt1 and foxl3. The existence of dmrt1 and foxl3 allows environmental factors to influence the sex fate decision in vertebrates.

scholarly journals Transcription factor AP2 controls cnidarian germ cell induction

Science ◽  
2020 ◽  
Vol 367 (6479) ◽  
pp. 757-762 ◽  
Author(s):  
Timothy Q. DuBuc ◽  
Christine E. Schnitzler ◽  
Eleni Chrysostomou ◽  
Emma T. McMahon ◽  
Febrimarsa ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Adult Stem Cells ◽  
Germ Line ◽  
Cell Induction ◽  
Cell Commitment ◽  
I Cells

Clonal animals do not sequester a germ line during embryogenesis. Instead, they have adult stem cells that contribute to somatic tissues or gametes. How germ fate is induced in these animals, and whether this process is related to bilaterian embryonic germline induction, is unknown. We show that transcription factor AP2 (Tfap2), a regulator of mammalian germ lines, acts to commit adult stem cells, known as i-cells, to the germ cell fate in the clonal cnidarian Hydractinia symbiolongicarpus. Tfap2 mutants lacked germ cells and gonads. Transplanted wild-type cells rescued gonad development but not germ cell induction in Tfap2 mutants. Forced expression of Tfap2 in i-cells converted them to germ cells. Therefore, Tfap2 is a regulator of germ cell commitment across germ line–sequestering and germ line–nonsequestering animals.

scholarly journals Extensive nuclear gyration and pervasive non-genic transcription during primordial germ cell development in zebrafish

Development ◽  
2020 ◽  
pp. dev.193060
Author(s):  
Stefan Redl ◽  
Antonio M. de Jesus Domingues ◽  
Edoardo Caspani ◽  
Stefanie Möckel ◽  
Willi Salvenmoser ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Genital Ridge ◽  
Non Coding Rna ◽  
Pathway Activation ◽  
Pirna Pathway ◽  
Time Point

Primordial germ cells (PGCs) are the precursors of germ cells, which migrate to the genital ridge during early development. Relatively little is known about PGCs after their migration. We studied this post-migratory stage using microscopy and sequencing techniques, and found that many PGC-specific genes, including genes known to induce PGC fate in the mouse, are only activated several days after migration. At this same time point, PGC nuclei become extremely gyrated, displaying general broad opening of chromatin and high levels of intergenic transcription. This is accompanied by changes in nuage morphology, expression of large loci (PGC-Expressed non-coding RNA Loci, PERLs) that are enriched for retro-transposons and piRNAs, and a rise in piRNA biogenesis signatures. Interestingly, no nuclear Piwi protein could be detected at any time point, indicating that the zebrafish piRNA pathway is fully cytoplasmic. Our data show that the post-migratory stage of zebrafish PGCs holds many cues to both germ cell fate establishment and piRNA pathway activation.

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