Large Drosophila Germline piRNA Clusters are Evolutionarily Labile and Dispensable for Transposon Regulation
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ABSTRACT:
PROVIDER: PRJNA730546 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR14569543_1.fastq.gz | Fastqsanger.gz | |||
| SRR14569543_2.fastq.gz | Fastqsanger.gz | |||
| SRR14569544_1.fastq.gz | Fastqsanger.gz | |||
| SRR14569544_2.fastq.gz | Fastqsanger.gz | |||
| SRR14569545.fastq.gz | Fastqsanger.gz |
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Project description:PIWI proteins and their guiding Piwi-interacting small RNAs (piRNAs) are crucial for fertility and transposon defense in the animal germline. In most species, the majority of piRNAs are produced from distinct large genomic loci, called piRNA clusters. It is assumed that germline-expressed piRNA clusters, particularly in Drosophila, act as master regulators to control the activity of transposons dispersed across the genome. Here, using synteny analysis, we show that large germline clusters are evolutionarily labile, arise at loci characterized by recurrent chromosomal rearrangements, and are mostly species-specific across the Drosophila genus. By engineering chromosomal deletions in D. melanogaster, we demonstrate that the three largest germline clusters, which the generation of >40% of all transposon-targeting piRNAs depend on, are neither required for fertility nor for the regulation of transposon activity in trans. We provide further evidence that dispersed active elements, rather than the regulatory action of large Drosophila germline clusters in trans, may be central for transposon defense.
2021-05-31 | GSE174561 | GEO
Project description:PIWI proteins and their guiding Piwi-interacting small RNAs (piRNAs) are crucial for fertility and transposon defense in the animal germline. In most species, the majority of piRNAs are produced from distinct large genomic loci, called piRNA clusters. It is assumed that germline-expressed piRNA clusters, particularly in Drosophila, act as principal regulators to control transposons dispersed across the genome. Here, using synteny analysis, we show that large clusters are evolutionarily labile, arise at loci characterized by recurrent chromosomal rearrangements, and are mostly species-specific across the Drosophila genus. By engineering chromosomal deletions in D. melanogaster, we demonstrate that the three largest germline clusters, which account for the accumulation of >40% of all transposon-targeting piRNAs in ovaries, are neither required for fertility nor for transposon regulation in trans. We provide further evidence that dispersed elements, rather than the regulatory action of large Drosophila germline clusters in trans, may be central for transposon defense.
| S-EPMC8516431 | biostudies-literature
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
Project description:Unistrand piRNA clusters are an evolutionarily conserved mechanism to suppress endogenous retroviruses across the Drosophila genus
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Project description:The PIWI-interacting RNA (piRNA) pathway is an important mechanism to suppress transposon activation in the germline that is highly conserved between Drosophila and mammals. This pathway starts from transcribing piRNA clusters to generate long piRNA precursors. The majority of piRNA clusters lacks a conventional promoter, and therefore their transcription is considered to utilize a noncanonical mechanism. However, information regarding transcriptional regulation of piRNA clusters is limited. Here, we report that the fly KAT6 acetyltransferase, Enok, is important for transposon silencing in the germline. Further small RNA-seq analysis revealed that Enok is critical for piRNA production from a specific subset of piRNA clusters including 42AB, one of the two major sources of piRNAs. Enok is the major enzyme for establishing the H3K23ac mark, and was shown to promote gene expression by acetylating H3K23. Surprisingly, our RNA-seq and ChIP-seq/ChIP-qPCR results suggest that Enok regulates expression of genes involved in the piRNA production by H3K23ac-dependent mechanisms, and also promotes transcription at piRNA clusters through H3K23ac-independent pathways. Our co-immunoprecipitation assay further suggests that Enok interacts with RNA polymerase II to facilitate transcription of piRNA clusters. Taken together, our study provides novel insights into the regulation of noncanonical transcription at piRNA clusters and transposon silencing.
2021-01-07 | GSE105099 | GEO
Project description:The transposon silencing piRNAs are produced from precursors that are encoded by heterochromatic clusters and processed in the perinuclear nuage. We show that the Drosophila nuclear DEAD box protein UAP56, previously implicated in mRNA splicing and nuclear export, co-localizes with the cluster-associated HP1 homologue Rhino. Prominent nuclear foci containing Rhi and UAP56 localize directly across the nuclear envelope from Vasa, a conserved DEAD box protein and core nuage component that is required for piRNA production, and piRNA precursors immunoprecipitate with both UAP56 and Vasa. A uap56 point mutation that prevents UAP56 protein co-localization with Rhino also disrupts nuage organization, transposon silencing, and expression of dual strand piRNA clusters. By contrast, this allele significantly increases ectopic piRNAs from protein coding genes. We therefore propose that UAP56 and Vasa organize a piRNA-processing compartment that spans the nuclear envelope, increasing the efficiency and specificity of piRNA biogenesis. 3 replicates of each sample (uap56, vasa), total RNA samples hybridized to tiling array.
2012-11-28 | E-GEOD-35636 | biostudies-arrayexpress
Project description:piRNAs silence transposons during germline development. In Drosophila, transcripts from heterochromatic clusters are processed into primary piRNAs in the perinuclear nuage. The nuclear DEAD box protein UAP56 has been previously implicated in mRNA splicing and export, whereas the DEAD box protein Vasa has an established role in piRNA production and localizes to nuage with the piRNA binding PIWI proteins Ago3 and Aub. We show that UAP56 colocalizes with the cluster-associated HP1 variant Rhino, that nuage granules containing Vasa localize directly across the nuclear envelope from cluster foci containing UAP56 and Rhino, and that cluster transcripts immunoprecipitate with both Vasa and UAP56. Significantly, a charge-substitution mutation that alters a conserved surface residue in UAP56 disrupts colocalization with Rhino, germline piRNA production, transposon silencing, and perinuclear localization of Vasa. We therefore propose that UAP56 and Vasa function in a piRNA-processing compartment that spans the nuclear envelope.
| S-EPMC3499805 | biostudies-literature
Project description:The PIWI-interacting RNA (piRNA) pathway is an important mechanism to suppress transposon activation in the germline that is highly conserved between Drosophila and mammals. This pathway starts from transcribing piRNA clusters to generate long piRNA precursors. The majority of piRNA clusters lacks a conventional promoter, and therefore their transcription is considered to utilize a noncanonical mechanism. However, information regarding transcriptional regulation of piRNA clusters is limited. Here, we report that the fly KAT6 acetyltransferase, Enok, is important for transposon silencing in the germline. Further small RNA-seq analysis revealed that Enok is critical for piRNA production from a specific subset of piRNA clusters including 42AB, one of the two major sources of piRNAs. Enok is the major enzyme for establishing the H3K23ac mark, and was shown to promote gene expression by acetylating H3K23. Surprisingly, our RNA-seq and ChIP-seq/ChIP-qPCR results suggest that Enok regulates expression of genes involved in the piRNA production by H3K23ac-dependent mechanisms, and also promotes transcription at piRNA clusters through H3K23ac-independent pathways. Our co-immunoprecipitation assay further suggests that Enok interacts with RNA polymerase II to facilitate transcription of piRNA clusters. Taken together, our study provides novel insights into the regulation of noncanonical transcription at piRNA clusters and transposon silencing.
2021-01-07 | GSE133847 | GEO
Project description:The PIWI-interacting RNA (piRNA) pathway is an important mechanism to suppress transposon activation in the germline that is highly conserved between Drosophila and mammals. This pathway starts from transcribing piRNA clusters to generate long piRNA precursors. The majority of piRNA clusters lacks a conventional promoter, and therefore their transcription is considered to utilize a noncanonical mechanism. However, information regarding transcriptional regulation of piRNA clusters is limited. Here, we report that the fly KAT6 acetyltransferase, Enok, is important for transposon silencing in the germline. Further small RNA-seq analysis revealed that Enok is critical for piRNA production from a specific subset of piRNA clusters including 42AB, one of the two major sources of piRNAs. Enok is the major enzyme for establishing the H3K23ac mark, and was shown to promote gene expression by acetylating H3K23. Surprisingly, our RNA-seq and ChIP-seq/ChIP-qPCR results suggest that Enok regulates expression of genes involved in the piRNA production by H3K23ac-dependent mechanisms, and also promotes transcription at piRNA clusters through H3K23ac-independent pathways. Our co-immunoprecipitation assay further suggests that Enok interacts with RNA polymerase II to facilitate transcription of piRNA clusters. Taken together, our study provides novel insights into the regulation of noncanonical transcription at piRNA clusters and transposon silencing.
2021-01-07 | GSE105025 | GEO
Project description:The transposon silencing piRNAs are produced from precursors that are encoded by heterochromatic clusters and processed in the perinuclear nuage. We show that the Drosophila nuclear DEAD box protein UAP56, previously implicated in mRNA splicing and nuclear export, co-localizes with the cluster-associated HP1 homologue Rhino. Prominent nuclear foci containing Rhi and UAP56 localize directly across the nuclear envelope from Vasa, a conserved DEAD box protein and core nuage component that is required for piRNA production, and piRNA precursors immunoprecipitate with both UAP56 and Vasa. A uap56 point mutation that prevents UAP56 protein co-localization with Rhino also disrupts nuage organization, transposon silencing, and expression of dual strand piRNA clusters. By contrast, this allele significantly increases ectopic piRNAs from protein coding genes. We therefore propose that UAP56 and Vasa organize a piRNA-processing compartment that spans the nuclear envelope, increasing the efficiency and specificity of piRNA biogenesis.
2012-11-28 | GSE35636 | GEO