Distinct mechanisms of germ cell factor regulation for an inductive germ cell fate
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ABSTRACT:
ORGANISM(S): Patiria miniata
PROVIDER: GSE196654 | GEO | 2022/11/16
REPOSITORIES: GEO
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Project description:Embryonic stem cells (ESCs) and primordial germ cells (PGCs) express many pluripotency-associated genes, but ESCs do not normally undergo conversion into PGCs. Thus, we predicted that there is a mechanism that represses PGC-related gene expression in ESCs. Here we identify genes involved in this putative mechanism, by using an ESC line with a Vasa reporter for an RNAi screen of transcription factor genes expressed in ESCs. We identify 5 genes that result in the expression of Vasa when silenced. Of these, Max is the most striking. Transcriptome analysis reveals that Max knockdown (KD) in ESCs results in selective, global derepression of germ-cell-specific genes. Max interacts with histone H3K9 methyltransferases and associates with the germ-cell-specific genes in ESCs. In addition, Max-KD results in a decrease in histone H3K9 dimethylation at their promoter regions. We propose that Max is part of a protein complex that acts as a repressor of germ-cell-related genes in ESCs. Gene expression profile of Vasa-positive cells isolated from Max knockdown ESCs was compared to that of normal ESCs and in vivo PGCs. As an ESCs sample, a mouse embryonic stem cell line that carries a Venus reporter driven by the Vasa gene promoter (VV3) was used for this study. VV3 ESCs were transfected with non-silencing negative control siRNA (AllStars) or siRNA against the Max gene. Vasa-positive cells were purified using fluorescence-activated cell sorting (FACS). As a PGCs sample, a mouse strain that carries a germ-cell-specific GFP reporter (Oct4M-NM-^TPE-GFP) was used. PGCs were also purified using FACS. RNA samples were isolated from each sample and labeled and hybridized to Agilent microarrays. Three biological replicates were performed for each group of samples.
2013-05-01 | E-GEOD-45181 | biostudies-arrayexpress
Project description:The Nanos family of RNA-binding proteins has been implicated in the specification of primordial germ cells (PGCs) in a wide range of metazoans, but the underlying mechanisms remain poorly understood. We have profiled the transcriptome of PGCs lacking the nanos homologues nos-1 and nos-2 in C. elegans using cell sorting and RNA-seq. nos-1nos-2 PGCs fail to silence hundreds of genes normally expressed in oocytes and somatic cells, a phenotype reminiscent of PGCs lacking the repressive PRC2 complex. The nos-1nos-2 phenotype depends on LIN-15B, a broadly expressed synMuvB class transcription factor known to antagonize PRC2 activity in somatic cells. LIN-15B is maternally-inherited by all embryonic cells and is down-regulated specifically in PGCs in a nos-1nos-2-dependent manner. Consistent with LIN-15B being a critical target of Nanos regulation, inactivation of maternal LIN-15B restores fertility to nos-1nos-2 mutants. These studies demonstrate a central role for Nanos in reprogramming the transcriptome of primordial germ cells away from an oocyte/somatic fate by down-regulating an antagonist of PRC2 activity.
2017-12-05 | GSE100651 | GEO
Project description:The Nanos family of RNA-binding proteins has been implicated in the specification of primordial germ cells (PGCs) in a wide range of metazoans, but the underlying mechanisms remain poorly understood. We have profiled the transcriptome of PGCs lacking the nanos homologues nos-1 and nos-2 in C. elegans using cell sorting and RNA-seq. nos-1nos-2 PGCs fail to silence hundreds of genes normally expressed in oocytes and somatic cells, a phenotype reminiscent of PGCs lacking the repressive PRC2 complex. The nos-1nos-2 phenotype depends on LIN-15B, a broadly expressed synMuvB class transcription factor known to antagonize PRC2 activity in somatic cells. LIN-15B is maternally-inherited by all embryonic cells and is down-regulated specifically in PGCs in a nos-1nos-2-dependent manner. Consistent with LIN-15B being a critical target of Nanos regulation, inactivation of maternal LIN-15B restores fertility to nos-1nos-2 mutants. These studies demonstrate a central role for Nanos in reprogramming the transcriptome of primordial germ cells away from an oocyte/somatic fate by down-regulating an antagonist of PRC2 activity.
2017-12-08 | GSE100652 | GEO
Project description:Embryonic stem cells (ESCs) and primordial germ cells (PGCs) express many pluripotency-associated genes, but ESCs do not normally undergo conversion into PGCs. Thus, we predicted that there is a mechanism that represses PGC-related gene expression in ESCs. Here we identify genes involved in this putative mechanism, by using an ESC line with a Vasa reporter for an RNAi screen of transcription factor genes expressed in ESCs. We identify 5 genes that result in the expression of Vasa when silenced. Of these, Max is the most striking. Transcriptome analysis reveals that Max knockdown (KD) in ESCs results in selective, global derepression of germ-cell-specific genes. Max interacts with histone H3K9 methyltransferases and associates with the germ-cell-specific genes in ESCs. In addition, Max-KD results in a decrease in histone H3K9 dimethylation at their promoter regions. We propose that Max is part of a protein complex that acts as a repressor of germ-cell-related genes in ESCs.
2013-05-01 | GSE45181 | GEO
Project description:The ability to distinguish non-self from self is the key characteristic for any defense system. piRNAs function as guardians of the genome by silencing non-self nucleic acids and transposable elements in animals. Many piRNA factors are enriched in perinuclear germ granules, but whether their localization is required for piRNA biogenesis or function is not known. Here we show that GLH/VASA helicase mutants exhibit defects in forming perinuclear condensates containing PIWI and other small RNA cofactors. These mutant animals produce largely normal levels of piRNA but are defective in triggering piRNA silencing. Strikingly, while many piRNA targets are activated in GLH mutants, we observed that hundreds of endogenous genes are aberrantly silenced by piRNAs. This defect in self versus non-self recognition was also observed in other mutants where perinuclear P granules are disrupted. Together, our results argue that perinuclear germ granules function critically to promote the fidelity of piRNA-based transcriptome surveillance in C. elegans and preserve self versus non-self distinction.
2022-08-05 | PXD033506 | Pride
Project description:DEAD-box RNA helicase Vasa is required for gonad development and fertility in multiple animals. In Drosophila, Vasa performs essential functions in oogenesis, including the maintenance of germline stem cells (GSCs), piRNA silencing of mobile elements, translation regulation, and primordial germ cell specification. Despite its evident significance, the mechanistic basis of Vasa action and its precise role in spermatogenesis become incomprehensible. Several papers affirm the fertility of males carrying vasa mutations. However, it is also shown that Vasa is essential for piRNA-mediated repression of Stellate genes needed for the maintenance of male fertility.Here we found that loss-of-function vasa mutations led to a rapid decline in GSC maintenance in the testes, a severe loss of total germ cell content, and a strong decrease in male fertility over time. With the aid of analysis of small RNA libraries, we revealed that collapse of piRNA biogenesis in the absence of vasa expression. Despite that, we did not reveal increasing cell death events in the early germ cells of vasa mutant testes. The introduction of the transgene rhino copy, encoding a nuclear component of the piRNA pathway, in vasa mutant background allowed us to rescue premeiotic stages of spermatogenesis, including GSC maintenance and the development of spermatogonia and spermatocytes. However, the progression of spermatocytes through meiosis and the fertility of the rhino transgene-rescued males were disrupted by strong Stellate gene derepression owing to the absence of corresponding piRNAs. We have shown that Vasa functions in spermatogenesis are essential at two separate developmental stages: in GSCs for their maintenance and in spermatocytes for the repression of Stellate genes.
2024-08-02 | GSE269988 | GEO
Project description:DEAD-box RNA helicase Vasa is required for gonad development and fertility in multiple animals. In Drosophila, Vasa performs essential functions in oogenesis, including the maintenance of germline stem cells (GSCs), piRNA silencing of mobile elements, translation regulation, and primordial germ cell specification. Despite its evident significance, the mechanistic basis of Vasa action and its precise role in spermatogenesis become incomprehensible. Several papers affirm the fertility of males carrying vasa mutations. However, it is also shown that Vasa is essential for piRNA-mediated repression of Stellate genes needed for the maintenance of male fertility.Here we found that loss-of-function vasa mutations led to a rapid decline in GSC maintenance in the testes, a severe loss of total germ cell content, and a strong decrease in male fertility over time. With the aid of analysis of small RNA libraries, we revealed that collapse of piRNA biogenesis in the absence of vasa expression. Despite that, we did not reveal increasing cell death events in the early germ cells of vasa mutant testes. The introduction of the transgene rhino copy, encoding a nuclear component of the piRNA pathway, in vasa mutant background allowed us to rescue premeiotic stages of spermatogenesis, including GSC maintenance and the development of spermatogonia and spermatocytes. However, the progression of spermatocytes through meiosis and the fertility of the rhino transgene-rescued males were disrupted by strong Stellate gene derepression owing to the absence of corresponding piRNAs. We have shown that Vasa functions in spermatogenesis are essential at two separate developmental stages: in GSCs for their maintenance and in spermatocytes for the repression of Stellate genes.
2024-08-02 | GSE269987 | GEO
Project description:Investigation of whole genome gene expression level changes in nanos(RNAi) Schmidtea mediterranea, compared to control animals. nanos(RNAi) animals are devoid of germ cells The samples analyzed in this study are further described in Wang, Y., Stary, JM., Wilhelm, JE. and Newmark, PA. 2010. A eight chip study using total RNA recovered from asexual nanos(RNAi), asexual control, juvenile sexual nanos(RNAi), and juvenile sexual control animals. Each chip measures the expression level of 16,797 ESTs from S. mediterranea with 10 60-mer probe pairs (PM/MM) per gene, with two-fold technical redundancy.
2010-09-01 | E-GEOD-22797 | biostudies-arrayexpress
Project description:Investigation of whole genome gene expression level changes in nanos(RNAi) Schmidtea mediterranea, compared to control animals. nanos(RNAi) animals are devoid of germ cells The samples analyzed in this study are further described in Wang, Y., Stary, JM., Wilhelm, JE. and Newmark, PA. 2010.
2010-09-01 | GSE22797 | GEO
Project description:RNA-seq experiments to identify gene expression changes following miracidia to sporocyst transformation in Schistosoma mansoni. Schistosomes infect hundreds of millions of people in the developing world. Transmission of these parasites relies on a stem cell-driven, clonal expansion of larvae inside a molluscan intermediate host. How this novel asexual reproductive strategy relates to current models of stem cell maintenance and germline specification is unclear. Here, we demonstrate that this proliferative larval cell population (germinal cells) shares some molecular signatures with stem cells from diverse organisms, in particular neoblasts of planarians (free-living relatives of schistosomes). We identify two distinct germinal cell lineages that differ in their proliferation kinetics and expression of a nanos ortholog. We show that a vasa PL10 homolog is required for proliferation and maintenance of both populations; whereas, argonaute2 and a fibroblast growth factor receptor-encoding gene are required only for nanos-negative cells. Our results suggest that an ancient stem cell-based developmental program may have enabled the evolution of the complex life-cycle of parasitic flatworms. Total RNA was purified from ~10,000 freshly hatched miracidia or sporocysts 48 h post-transformation.
2013-12-31 | E-GEOD-48282 | biostudies-arrayexpress