Piwi is a key regulator of both somatic and germline stem cells in the Drosophila testis
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE68997 | GEO | 2015/05/23
SECONDARY ACCESSION(S): PRJNA284269
REPOSITORIES: GEO
Similar Datasets
Project description:The Piwi-piRNA pathway is well known for its germline function, yet its somatic role remains elusive. We show here that Piwi is required autonomously not only for germline stem cell (GSC) but also for somatic cyst stem cell (CySC) maintenance in the Drosophila testis. Reducing Piwi activity in the testis caused defects in CySC differentiation. Accompanying this, GSC daughters expanded beyond the vicinity of the hub but failed to differentiate further. Moreover, Piwi deficient in nuclear localization caused similar defects in somatic and germ cell differentiation, which was rescued by somatic Piwi expression. To explore the underlying molecular mechanism, we identified Piwi-bound piRNAs that uniquely map to a gene key for gonadal development, Fasciclin 3, and demonstrate that Piwi regulates its expression in somatic cyst cells. Our work reveals the cell-autonomous function of Piwi in both somatic and germline stem cell types, with somatic function possibly via its epigenetic mechanism. Examination of Piwi-piRNAs in fly testis
2015-05-23 | E-GEOD-68997 | biostudies-arrayexpress
Project description:Stem cells reside in a specialized microenvironment, called niche, which provides essential signals controlling stem cell behavior. Proper niche architecture is a key for normal stem cell function, yet only few upstream regulators are known. Here we report that the Hox transcription factor Abd-B, active in pre-meiotic spermatocytes, affects niche positioning in the Drosophila testis by regulating integrin localization in differentiated somatic cyst cells. Loss of Abd-B results in cell non-autonomous effects within the niche including centrosome misorientation in germline stem cells (GSCs) and reduced GSC divisions in larval testis, leading to a dramatic reduction of pre-meiotic stages in adult testes. By identifying Abd-B binding regions throughout the genome, we find that Abd-B mediates its effects on niche function by directly controlling at multiple levels the localization and thus signaling activity of the Sevenless (Sev) ligand, Bride of Sevenless (Boss), via its direct targets src42A and sec63. In sum, our data show for the first time that Abd-B through local signaling provides positional cues for integrin localization, which is critical for niche localization and architecture, and ensures proper niche function and GSC activity. DamID (DNA adenine methyltransferase identification) method was used to identify direct Abd-B target genes in the Drosophila 3rd instar larval testis
2013-12-30 | GSE53709 | GEO
Project description:Stem cells reside in a specialized microenvironment, called niche, which provides essential signals controlling stem cell behavior. Proper niche architecture is a key for normal stem cell function, yet only few upstream regulators are known. Here we report that the Hox transcription factor Abd-B, active in pre-meiotic spermatocytes, affects niche positioning in the Drosophila testis by regulating integrin localization in differentiated somatic cyst cells. Loss of Abd-B results in cell non-autonomous effects within the niche including centrosome misorientation in germline stem cells (GSCs) and reduced GSC divisions in larval testis, leading to a dramatic reduction of pre-meiotic stages in adult testes. By identifying Abd-B binding regions throughout the genome, we find that Abd-B mediates its effects on niche function by directly controlling at multiple levels the localization and thus signaling activity of the Sevenless (Sev) ligand, Bride of Sevenless (Boss), via its direct targets src42A and sec63. In sum, our data show for the first time that Abd-B through local signaling provides positional cues for integrin localization, which is critical for niche localization and architecture, and ensures proper niche function and GSC activity. DamID (DNA adenine methyltransferase identification) method was used to identify direct Abd-B target genes in the Drosophila 3rd instar larval testis Dam was fused to the N terminus of Abd-B and transgenic flies were generated. For identifying Abd-B targets in the Drosophila testis the fusion protein was expressed from the uninduced minimal Hsp70 promoter of the UAS vector pUAST (Brand and Perrimon, 1993). As a control for nonspecific Dam activity, transgenic flies expressing the Dam alone were used (Choksi et al., 2006). Subsequently, genomic DNA was extracted from 3rd instar larval testes, expressing either the Dam-Abd-B fusion protein or the Dam protein alone using a specific protocol (Tolhuis et al., 2011); and van Steensel personal communication). Two individual replicates, for Dam-AbdB and Dam alone, have been generated. Following a methylation-sensitive DNA digestion and PCR amplification, DNA fragments from Dam-Abd-B and control DNA were labeled and hybridized to genomic Affymetrix arrays in duplicates (Protocol available at M-bM-^@M-^\www.flychip.org.ukM-bM-^@M-^]).
2013-12-30 | E-GEOD-53709 | biostudies-arrayexpress
Project description:The maintenance and differentiation of highly potent animal stem cells generates an epigenetic cycle that underlies development. Drosophila female germline stem cells (GSC) produce cystoblast daughters that differentiate into nurse cells and oocytes. Developmental chromatin analysis profiling the differentiation of GSCs into cystoblasts and NCs of increasing ploidy shows that cystoblasts start developing by forming heterochromatin while in a transient syncytial state, the germline cyst, reminiscent of early embryonic cells. The open GSC chromatin state is further restricted by Polycomb repression of targets that include testis expressed genes briefly active in early female germ cells. Like other highly potent stem cells, GSC metabolism is reprogrammed and Myc-dependent growth is upregulated by altering mitochondrial membrane transport, gluconeogenesis and other processes. Thus, the animal generational cycle comprises similar but distinct maternal and zygotic stem cell epigenetic cycles. We propose that the pluripotent stem cell state and daughter cell differentiation were shaped by the pressure to resist transposon activity over evolutionary time scales. In this GEO submission, we present data and analyses pertaining to H3K27ac, H3K27me3, and H3K9me3 ChIPseq, ATACseq, and RNAseq of Germline Stem Cells (GSCs) and Nurse Cells (NCs) from Drosophila melanogaster ovaries.
2023-08-16 | GSE229943 | GEO
Project description:Transposable elements (TEs) can damage genomes, thus organisms employ a variety of mechanisms to repress TE expression. The PIWI-piRNA pathway is a small RNA pathway that represses TE expression in the germline of animals. Here we explore the function of the pathway in the somatic stem cells of Hydra, a long-lived freshwater cnidarian. Hydra have three stem cell populations, all of which express PIWI proteins; endodermal and ectodermal epithelial stem cells are somatic, whereas the interstitial stem cells have germline competence. To study somatic function of the pathway we isolated piRNAs from Hydra that lack the interstitial lineage and found that these somatic piRNAs map predominantly to TE transcripts and display the conserved sequence signatures typical of germline piRNAs. Three lines of evidence suggest that the PIWI-piRNA pathway represses TEs in Hydra epithelial stem cells. First, epithelial knockdown of the Hydra piwi gene hywi resulted in upregulation of TE expression. Second, degradome sequencing revealed evidence of PIWI-mediated cleavage of TE RNAs in epithelial cells using the ping-pong mechanism. Finally, we demonstrated a direct association between Hywi protein and TE transcripts in epithelial cells using RNA immunoprecipitation. Altogether, our data reveal that the PIWI-piRNA pathway represses TE expression in the somatic cell lineages of Hydra, which we propose contributes to the extreme longevity of the organism. Furthermore, our results, in combination with others, suggest that somatic TE repression is an ancestral function of the PIWI-piRNA pathway.
2019-08-07 | GSE135440 | GEO
Project description:In many metazoans, germ cells are separated from somatic lineages early in development and maintain their identity throughout life. Here we show that a Polycomb group (PcG) component, Enhancer of Zeste [E(z)] H3K27me3-specific methyltransferase, maintains germline identity in Drosophila adult testes. We find excessive early-stage somatic gonadal cells in E(z) mutant testes, which originate from both over-proliferative cyst stem cells and germ cells turning on an early-stage somatic cell marker. Using complementary lineage-tracing experiments in E(z) mutant testes, a portion of excessive early-stage somatic gonadal cells are found to derive from early-stage germ cells, including germline stem cells. Interestingly, knocking down E(z) specifically in somatic cells caused this germline-to-soma change, suggesting a non-cell autonomous role of E(z) to antagonize somatic identity in germ cells. Using fly testis specifically expressing E(z) shmiR RNAi in germ cells by nos promoter driven GAL4>UAS system, ChIPseq with H3K27me3 antibody was performed, where H3K27me3 is only detected in somatic cells.
2014-05-02 | E-GEOD-53238 | biostudies-arrayexpress
Project description:Somatic cells can be reprogrammed to pluripotency using different methods. In comparison to pluripotent cells obtained through somatic nuclear transfer, induced pluripotent stem cells (iPSCs) exhibit a higher number of epigenetic errors. Furthermore, most of these abnormalities have been described to be intrinsic to the iPSC technology. Here we investigate whether the aberrant epigenetic patterns detected in iPSCs are specific to transcription factor-mediated reprogramming. We used germline stem cells (GSCs), which are the only adult cell type that can be converted into pluripotent cells (gPSCs) under specific culture conditions, and compared GSC-derived iPSCs and gPSCs at the transcriptomic, epigenetic and functional level. Our results show that both reprogramming methods generate indistinguishable states of pluripotency. GSC-derived iPSCs and gPSCs retained similar levels of donor cell-type memory and exhibited comparable numbers of reprogramming errors. Therefore, our study demonstrates that the epigenetic memory detected in iPSCs is not intrinsic to transcription-factor mediated reprogramming. Total RNA from 12 different in vitro mouse cell lines, 2 technical replicates per sample: germline stem cells (GSCs, 2 independent cell lines), GSC-derived induced pluripotent stem cells (iPSCs, 4 independent cell lines), germline-derived pluripotent stem cells (gPSCs, 4 independent cell lines), embryonic stem cells (ESCs), fibroblast-derived induced pluripotent stem cells (Fib-iPSCs)
2015-03-07 | E-GEOD-66613 | biostudies-arrayexpress
Project description:Germline stem cell self-renewal and differentiation are required for sustained production of gamates. GSC differentiation in drosophila requires expression of setdb1 by the somatic niche, however its function is not known. We used microarray analysis to determine what genes does setdb1 regulate to affect differentiation.
2016-08-31 | GSE78080 | GEO
Project description:LEM Domain proteins are key components of the nuclear lamina. Mutations in LEM-D proteins cause dystrophic diseases associated with compromised adult stem cells, yet it remains unclear how LEM-D proteins support stem cell function. Studies described here use the homologue of the LEM-D protein emerin in Drosophila, Otefin (Ote) as a model to understand LEM-D protein function in adult stem cells. Loss of Ote causes female sterility due to a complex germline stem cell (GSC) phenotype that includes both an early block in germline differentiation followed by GSC death. In vivo cell cycle analysis revealed that ote mutant GSCs display a lengthened S phase.We find that loss of the DNA Damage Response (DDR) Chk2 is able to not only rescue the lengthened S phase, but also GSC death and the block in germline differentiation. Activation of detrimental checkpoint in absence of Ote is conserved in both male and female GSCs and surprisingly occurs independent of detectable canonical DDR triggers, including transposon de-repression and DNA damage. Two defects were found to occur upstream of Chk2 activation: nuclear lamina morphological defects and altered heterochromatin organization. Together, our data identify the primary cause for a compromised adult stem cell population in the absence of a LEM-D protein.
2018-07-03 | GSE95309 | GEO
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