Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA154867 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:This SuperSeries is composed of the following subset Series: GSE32180: MIWI catalysis is required for piRNA amplification-independent LINE1 transposon silencing [microarray] GSE32184: MIWI catalysis is required for piRNA amplification-independent LINE1 transposon silencing [deep sequencing] Refer to individual Series
2011-11-30 | E-GEOD-32183 | biostudies-arrayexpress
Project description:MIWI catalysis is required for piRNA amplification-independent LINE1 transposon silencing
| PRJNA147395 | ENA
Project description:MIWI catalysis is required for piRNA amplification-independent LINE1 transposon silencing [deep sequencing]
| PRJNA154861 | ENA
Project description:Piwi proteins and piRNAs have conserved functions in transposonM- silencing. The murine Piwi proteins Mili and Miwi2 direct epigeneticM- LINE1 (L1) and intracisternal A particle (IAP) transposon silencingM- during genome reprogramming in the embryonic male germline. PiwiM- proteins are proposed to be piRNA-guided endonucleases that initiateM- secondary piRNA biogenesis . However the actual contribution of theirM- endonuclease activities to piRNA biogenesis and transposon silencingM- remain unknown. To investigate the role of Piwi-catalyzedM- endonucleolytic activity, we engineered point mutations in the mouseM- that substitute the second D to an A in the catalytic triad (DDH) ofM- Mili and Miwi2, generating the MiliDAH and Miwi2DAH alleles,M- M- respectively. Analysis of Mili-bound piRNAs from homozygous MiliDAHM- fetal gonadocytes revealed the failure of transposon piRNA amplification resulting in the stark reduction of piRNA bound withinM- Miwi2 ribonuclear particles (RNPs). We find that Mili-mediated piRNA amplification is selectively required for L1 but not IAP silencing.M- The defective piRNA pathway in MiliDAH mice results in spermatogenic failure and sterility. Surprisingly, homozygous Miwi2DAH mice areM- fertile, transposon silencing is established normally and no defectsM- in secondary piRNA biogenesis are observed. In addition, the hallmarks of piRNA amplification are observed in Miwi2-deficient gonadocytes. WeM- conclude that cycles of intra-Mili secondary piRNA biogenesis fuelM- piRNA amplification that is selectively required for L1 silencing.M-
2011-10-28 | E-MTAB-730 | biostudies-arrayexpress
Project description:The piRNA biogenesis machinery localizes to phase-separated nuage granules, but nuage function is not well understood. We therefore assayed nuage composition, piRNA expression, and transposon silencing in Drosophila mutants that disrupt piRNA precursor production and nuclear export, ping-pong amplification, and phased piRNA biogenesis. These mutations destabilize the genome and activate Chk2 signaling, and chk2/mnk double mutants were therefore analyzed in parallel. Aub and Vasa are required for ping-pong amplification, and Armi promotes phased piRNA processing. We show that Chk2 activation releases Aub and Vasa from nuage and that piRNA precursors are required for nuage localization of the ping-pong and phased biogenesis machinery. However, this analysis also indicates that Vasa, Aub, and Armi concentration in nuage is dispensable for piRNA production and transposon silencing, indicating that dispersed cytoplasmic proteins can drive these processes. We speculate that nuage sequesters silencing effectors, which are released by Chk2 in response to transposon mobilization.
2026-02-24 | GSE236035 | GEO
Project description:The piRNA machinery is known for its role in mediating epigenetic silencing of transposons. Recent studies suggest that this function also involves piRNA-guided cleavage of transposon-derived transcripts. As many piRNAs also appear to have the capacity to target diverse mRNAs, this raises the intriguing possibility that piRNAs may act extensively as siRNAs to degrade specific mRNAs. To directly test this hypothesis, we compared mouse PIWI (MIWI)-associated piRNAs with experimentally identified cleaved mRNA fragments from mouse testes, and observed cleavage sites that predominantly occur at position 10 from the 5' end of putative targeting piRNAs. We also noted strong biases for U and A residues at nucleotide positions 1 and 10, respectively, in both piRNAs and mRNA fragments, features that resemble the pattern of piRNA amplification by the 'ping-pong' cycle. Through mapping of MIWI-RNA interactions by CLIP-seq and gene expression profiling, we found that many potential piRNA-targeted mRNAs directly interact with MIWI and show elevated expression levels in the testes of Miwi catalytic mutant mice. Reporter-based assays further revealed the importance of base pairing between piRNAs and mRNA targets and the requirement for both the slicer activity and piRNA-loading ability of MIWI in piRNA-mediated target repression. Importantly, we demonstrated that proper turnover of certain key piRNA targets is essential for sperm formation. Together, these findings reveal the siRNA-like function of the piRNA machinery in mouse testes and its central requirement for male germ cell development and maturation.
2015-04-09 | GSE67683 | GEO
Project description:The mouse PIWI-interacting RNA (piRNA) pathway provides anti-transposon immunity to the developing male germline by directing transposon DNA methylation. The first step in this process is the recruitment of SPOCD1 to young LINE1 loci 1 followed in the second step by piRNA-mediated tethering of the PIWI protein MIWI2 (PIWIL4) to the nascent transposon transcript. To protect the germline, the piRNA pathway needs to methylate all active transposon copies but how this is achieved remains unknown. Here, we show that nuclear piRNA and de novo methylation factors are all euchromatic. We find that SPOCD1 directly interacts with the nuclear pore component TPR, which forms heterochromatin exclusion zones adjacent to nuclear pores. In foetal gonocytes undergoing piRNA-directed DNA methylation, TPR is found both at the nuclear periphery but also abundantly throughout the nucleoplasm. We found that the SPOCD1-TPR interaction is required for complete non-stochastic piRNA-directed LINE1 methylation. The loss of the SPOCD1-TPR interaction results in a fraction of SPOCD1 and other chromatin-bound piRNA factors to relocalise to constitutive heterochromatin where they are no longer accessible to MIWI2 and the de novo methylation machinery. We propose that TPR-mediated heterochromatin exclusion provides a nowhere-to-hide mechanism for SPOCD1-bound LINE1 loci throughout the nucleoplasm. In summary, the piRNA pathway has co-opted TPR to guarantee LINE1s are euchromatic and accessible to the piRNA and de novo methylation machineries.
2025-11-11 | PXD060850 | Pride
Project description:The mouse PIWI-interacting RNA (piRNA) pathway provides anti-transposon immunity to the developing male germline by directing transposon DNA methylation. The first step in this process is the recruitment of SPOCD1 to young LINE1 loci 1 followed in the second step by piRNA-mediated tethering of the PIWI protein MIWI2 (PIWIL4) to the nascent transposon transcript. To protect the germline, the piRNA pathway needs to methylate all active transposon copies but how this is achieved remains unknown. Here, we show that nuclear piRNA and de novo methylation factors are all euchromatic. We find that SPOCD1 directly interacts with the nuclear pore component TPR, which forms heterochromatin exclusion zones adjacent to nuclear pores. In foetal gonocytes undergoing piRNA-directed DNA methylation, TPR is found both at the nuclear periphery but also abundantly throughout the nucleoplasm. We found that the SPOCD1-TPR interaction is required for complete non-stochastic piRNA-directed LINE1 methylation. The loss of the SPOCD1-TPR interaction results in a fraction of SPOCD1 and other chromatin-bound piRNA factors to relocalise to constitutive heterochromatin where they are no longer accessible to MIWI2 and the de novo methylation machinery. We propose that TPR-mediated heterochromatin exclusion provides a nowhere-to-hide mechanism for SPOCD1-bound LINE1 loci throughout the nucleoplasm. In summary, the piRNA pathway has co-opted TPR to guarantee LINE1s are euchromatic and accessible to the piRNA and de novo methylation machineries.
2025-11-11 | PXD060851 | Pride
Project description:The piRNA machinery is known for its role in mediating epigenetic silencing of transposons. Recent studies suggest that this function also involves piRNA-guided cleavage of transposon-derived transcripts. As many piRNAs also appear to have the capacity to target diverse mRNAs, this raises the intriguing possibility that piRNAs may act extensively as siRNAs to degrade specific mRNAs. To directly test this hypothesis, we compared mouse PIWI (MIWI)-associated piRNAs with experimentally identified cleaved mRNA fragments from mouse testes, and observed cleavage sites that predominantly occur at position 10 from the 5' end of putative targeting piRNAs. We also noted strong biases for U and A residues at nucleotide positions 1 and 10, respectively, in both piRNAs and mRNA fragments, features that resemble the pattern of piRNA amplification by the 'ping-pong' cycle. Through mapping of MIWI-RNA interactions by CLIP-seq and gene expression profiling, we found that many potential piRNA-targeted mRNAs directly interact with MIWI and show elevated expression levels in the testes of Miwi catalytic mutant mice. Reporter-based assays further revealed the importance of base pairing between piRNAs and mRNA targets and the requirement for both the slicer activity and piRNA-loading ability of MIWI in piRNA-mediated target repression. Importantly, we demonstrated that proper turnover of certain key piRNA targets is essential for sperm formation. Together, these findings reveal the siRNA-like function of the piRNA machinery in mouse testes and its central requirement for male germ cell development and maturation. CLIP-Seq (Crosslinking Immunoprecipitation coupled with high-throughput sequencing) experiments targeting Miwi in isolated round spermatids from mouse testis.
2015-04-09 | E-GEOD-67683 | biostudies-arrayexpress
Project description:Nearly half of the mammalian genome is composed of repeated sequences. In Drosophila, PIWI proteins exert control over transposons. However, mammalian PIWI proteins, Miwi and Mili, partner with piRNAs that are depleted of repeat sequences, raising questions about a role for mammalian PIWIs in transposon control. A search for murine small RNAs that might program PIWI proteins for transposon suppression revealed developmentally regulated piRNA loci, some of which resemble transposon master control loci of Drosophila. We also find evidence of an adaptive amplification loop in which PIWI catalyzes formation of piRNA 5’ ends. Mili mutants de-repress L1 and IAP and lose DNA methylation of L1 elements, demonstrating an evolutionarily conserved role for PIWI proteins in transposon suppression. Keywords: small RNA profile, piRNA
2007-04-20 | GSE7414 | GEO