Drosophila melanogaster
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA299586 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR2749770_1.fastq.gz | Fastqsanger.gz | |||
| SRR2749770_2.fastq.gz | Fastqsanger.gz | |||
| SRR2749780_1.fastq.gz | Fastqsanger.gz | |||
| SRR2749780_2.fastq.gz | Fastqsanger.gz | |||
| SRR2749790.fastq.gz | Fastqsanger.gz |
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Project description:Small RNA silencing pathways protect genome integrity in part through establishing heterochromatin at transposon loci. In animals, this process requires piRNA-guided targeting of nuclear PIWI proteins to nascent transcripts. The molecular events contributing to heterochromatin formation upon PIWI binding to nascent RNA, a transient molecule at chromatin, are unknown. Here, we identify SFINX, a protein complex that is required for Piwi-mediated co-transcriptional silencing in Drosophila. It consists of Nxf2—a variant of the nuclear RNA export factor Nxf1/Tap, the mRNA export co-factor Nxt1/p15, and the Piwi-associated protein Panoramix. In the absence of Nxf2, Panoramix is targeted for degradation and piRNA-loaded Piwi is unable to establish heterochromatin. Consequently, nxf2 mutants exhibit severe transposon de-repression and are sterile. We show that within SFINX, Panoramix connects to the heterochromatin machinery while Nxf2 enables target silencing via nascent RNA. Thus, the Nxf2-Nxt1 heterodimer—despite having originated from core mRNA export machinery—has been repurposed for heterochromatin formation. Our data establish an unexpected link between nuclear small RNA biology and NXF-variants, which are widespread in animal lineages, but mostly lack ascribed functions.
2019-06-12 | PXD011201 | Pride
Project description:Heterochromatin, representing the silenced state of transcription, largely consists of transposon-enriched and highly repetitive sequences. Implicated in heterochromatin formation and transcriptional silencing in Drosophila are PIWI and repeat-associated small interfering RNAs (rasiRNAs). Despite this, the role of PIWI in rasiRNA expression and heterochromatic silencing remains unknown. Here we report the identification and characterization of 12,903 PIWI-interacting RNAs (piRNAs) in Drosophila, demonstrating that rasiRNAs represent a subset of piRNAs. Keywords: PIWI, piRNA, epigenetic regulation, heterochromatin
2007-10-25 | GSE9138 | GEO
Project description:A heterochromatin-dependent transcription machinery drives piRNA expression
| PRJNA382719 | ENA
Project description:Heterochromatin, representing the silenced state of transcription, largely consists of transposon-enriched and highly repetitive sequences. Implicated in heterochromatin formation and transcriptional silencing in Drosophila are PIWI and repeat-associated small interfering RNAs (rasiRNAs). Despite this, the role of PIWI in rasiRNA expression and heterochromatic silencing remains unknown. Here we report the identification and characterization of 12,903 PIWI-interacting RNAs (piRNAs) in Drosophila, demonstrating that rasiRNAs represent a subset of piRNAs. Keywords: PIWI, piRNA, epigenetic regulation, heterochromatin PIWI-associated small RNA cDNA library was sequenced for one time by high-throughput 454 pyrosequencing. Putative small RNA sequences were extracted and BLAST against the Drosophila melanogaster genome release 5. Presented here is a list of non-redundant PIWI-associated small RNAs, which have at least one genome match determined by BLASTn.
2007-10-24 | E-GEOD-9138 | biostudies-arrayexpress
Project description:In animal gonads, the PIWI-interacting RNA (piRNA) pathway guards genome integrity in part through the co-transcriptional gene silencing of transposon insertions. In Drosophila ovaries, piRNA-loaded Piwi detects nascent transposon transcripts and instructs heterochromatin formation through the Panoramix-induced co-transcriptional silencing (PICTS) complex, containing Panoramix, Nxf2 and Nxt1. Here, we report that the highly conserved dynein light chain LC8/Cut-up (Ctp) is an essential component of the PICTS complex. Loss of Ctp results in transposon de-repression and a reduction in repressive chromatin marks specifically at transposon loci. In turn, Ctp can enforce transcriptional silencing when artificially recruited to RNA and DNA reporters. We show that Ctp drives dimerisation of the PICTS complex through its interaction with conserved motifs within Panoramix. Artificial dimerisation of Panoramix bypasses the necessity for its interaction with Ctp, demonstrating that conscription of a protein from a ubiquitous cellular machinery has fulfilled a fundamental requirement for a transposon silencing complex.
2021-01-26 | PXD022105 | Pride
Project description:In animal gonads, the PIWI-interacting RNA (piRNA) pathway guards genome integrity in part through the co-transcriptional gene silencing of transposon insertions. In Drosophila ovaries, piRNA-loaded Piwi detects nascent transposon transcripts and instructs heterochromatin formation through the Panoramix-induced co-transcriptional silencing (PICTS) complex, containing Panoramix, Nxf2 and Nxt1. Here, we report that the highly conserved dynein light chain LC8/Cut-up (Ctp) is an essential component of the PICTS complex. Loss of Ctp results in transposon de-repression and a reduction in repressive chromatin marks specifically at transposon loci. In turn, Ctp can enforce transcriptional silencing when artificially recruited to RNA and DNA reporters. We show that Ctp drives dimerisation of the PICTS complex through its interaction with conserved motifs within Panoramix. Artificial dimerisation of Panoramix bypasses the necessity for its interaction with Ctp, demonstrating that conscription of a protein from a ubiquitous cellular machinery has fulfilled a fundamental requirement for a transposon silencing complex.
2021-01-26 | PXD022103 | Pride
Project description:The repression of transposable elements in eukaryotes often involves their transcriptional silencing via targeted chromatin modifications. In animal gonads, nuclear Argonaute proteins of the PIWI-clade complexed with small guide RNAs (piRNAs) serve as sequence specificity determinants in this process. How binding of nuclear PIWI-piRNA complexes to nascent transcripts orchestrates heterochromatin formation and transcriptional silencing is unknown. Here, we characterize CG9754/Silencio as an essential piRNA pathway factor that is required for Piwi-mediated transcriptional silencing in Drosophila. Ectopic targeting of Silencio to RNA or DNA is sufficient to elicit silencing independent of Piwi and known piRNA pathway factors. Instead, Silencio requires the H3K9 methyl-transferase Eggless/SetDB1 for its silencing ability. In agreement with this, SetDB1 but not Su(var)3-9 is required for Piwi-mediated transcriptional silencing genome-wide. Due to its interaction with the target-engaged Piwi-piRNA complex we suggest that Silencio acts as linker between the sequence specificity factor Piwi and the cellular heterochromatin machinery.
2015-11-19 | GSE74097 | GEO
Project description:In animal gonads, the PIWI-interacting RNA (piRNA) pathway guards genome integrity in part through the co-transcriptional gene silencing of transposon insertions. In Drosophila ovaries, piRNA-loaded Piwi detects nascent transposon transcripts and instructs heterochromatin formation through the Panoramix-induced co-transcriptional silencing (PICTS) complex, containing Panoramix, Nxf2 and Nxt1. Here, we report that the highly conserved dynein light chain LC8/Cut-up (Ctp) is an essential component of the PICTS complex. Loss of Ctp results in transposon de-repression and a reduction in repressive chromatin marks specifically at transposon loci. In turn, Ctp can enforce transcriptional silencing when artificially recruited to RNA and DNA reporters. We show that Ctp drives dimerisation of the PICTS complex through its interaction with conserved motifs within Panoramix. Artificial dimerisation of Panoramix bypasses the necessity for its interaction with Ctp, demonstrating that conscription of a protein from a ubiquitous cellular machinery has fulfilled a fundamental requirement for a transposon silencing complex.
2021-01-25 | GSE160855 | GEO
Project description:The PIWI-interacting RNA (piRNA) pathway protects animal genome integrity in part through establishing repressive heterochromatin at transposon loci. Silencing requires piRNA- guided targeting of nuclear PIWI proteins to nascent transposon transcripts, yet the subsequent molecular events are not understood. Here, we identify SFiNX (Silencing Factor interacting Nuclear eXport variant), an interdependent protein complex required for Piwi-mediated co-transcriptional silencing in Drosophila. SFiNX consists of Nxf2-Nxt1, a gonad- specific variant of the heterodimeric mRNA export receptor Nxf1-Nxt1, and the Piwi-associated protein Panoramix. SFiNX mutant flies are sterile and exhibit transposon de-repression because piRNA-loaded Piwi is unable to establish heterochromatin. Within SFiNX, Panoramix recruits the cellular heterochromatin machinery, while Nxf2 binds the nascent target RNA and licenses co-transcriptional silencing. Our results reveal an unexpected, RNA-export independent role for Nxf2 in nuclear small RNA biology and suggest that NXF-variants, which have largely unknown function in animals, are functionally linked to the genome-transposon conflict.
2019-04-17 | GSE120617 | GEO
Project description:The piRNA-interacting Piwi protein is involved in transcriptional silencing of transposable elements in ovaries of D. melanogaster. Here we characterized the genome-wide effect of nuclear Piwi elimination on the presence of the heterochromatic H3K9me3 mark and HP1a, as well as on the transcription-associated mark H3K4me2. Our results demonstrate that a significant increase in the H3K4me2 level upon nuclear Piwi loss is not accompanied by the alterations in H3K9me3 and HP1a levels for several germline-expressed transposons, suggesting that in this case Piwi prevents transcription by a mechanism distinct from H3K9 methylation. We found that the targets of Piwi-dependent chromatin repression are mainly related to the elements that display a higher level of H3K4me2 modification in the absence of silencing, i.e. most actively transcribed elements. We also show that Piwi-guided silencing does not significantly influence the chromatin state of dual-strand piRNA-producing clusters. In addition, host protein-coding gene expression is essentially not affected due to the nuclear Piwi elimination, but we noted an increase in small nuclear spliceosomal RNAs abundance and propose Piwi involvement in their posttranscriptional regulation. Our work reveals new aspects of transposon silencing in Drosophila, indicating that transcription of transposons can underpin their Piwi dependent silencing, while canonical heterochromatin marks are not obligatory for their repression. Examination of histone modifications in ovaries from two different fly lines- piwiNt/piwi2 (mutant) and piwi/+ (wildtype)
2014-05-19 | E-GEOD-56347 | biostudies-arrayexpress