Caenorhabditis elegans
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ABSTRACT:
PROVIDER: PRJNA307258 | ENA |
REPOSITORIES: ENA
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Project description:Double-stranded RNA (dsRNA) can cause specific gene silencing upon ingestion in many animals and is being developed as a pesticide to target essential genes in animal pests. However, the organismal response to ingested dsRNA that leads to eventual gene silencing within animals is unknown. In the worm C. elegans, ingested dsRNA is recruited into the RNA interference pathway by the dsRNA-binding protein RDE-4 for eventual gene silencing by Argonaute proteins. We found that when RDE-4 was expressed at high levels within a tissue, silencing by ingested dsRNA could occur in rde-4(-) somatic tissues but not in the rde-4(-) germline. Such silencing by dsRNA-derived mobile RNA had different Argonaute requirements and could escape inhibition by expressed repetitive DNA. Thus, our results suggest that, when animals ingest dsRNA, the ingested dsRNA and dsRNA-derived mobile RNAs use distinct mechanisms to silence genes.
2017-01-01 | GSE76424 | GEO
Project description:TDP-1, the C. elegans ortholog of TDP-43, limits the accumulation of double stranded RNA
| PRJNA261532 | ENA
Project description:In C. elegans worms, epigenetic information transmits transgenerationally. Still, it is unknown whether the effects transfer to the next generation inside or outside of the nucleus. Here we use the tractability of gene-specific double-stranded RNA-induced silencing to demonstrate that RNAi can be inherited independently of any nuclear factors via mothers that are genetically engineered to transmit only their ooplasm but not the oocytes’ nuclei to the next generation. We characterize the mechanisms and, utilizing RNA sequencing, chimeric worms and sequence polymorphism between different isolates, identify endogenous small RNAs which, similarly to exogenous siRNAs, are inherited in a nucleus-independent manner. From an historical perspective, these results might be regarded as partial vindication of discredited cytoplasmic inheritance theories from the 19th century, such as Darwin’s “pangenesis” theory.
2023-09-22 | GSE243434 | GEO
Project description:Through high-throuhgput RNA-sequencing, this study identifies mRNAs that are differentially expressed between plp-1(ok2155) and wild-type C. elegans. Analysed results are published in Development. 2020 Oct 13:dev.195578. doi: 10.1242/dev.195578. PMID: 33051256 Abstract of the publication: The germ line genome is guarded against invading foreign genetic elements by small RNA-dependent gene-silencing pathways. Components of these pathways localize to, or form distinct aggregates in the vicinity of, germ granules. These components and their dynamics in and out of granules are currently being intensively studied. Here, we report the identification of PLP-1, a C. elegans protein related to the human single-stranded nucleic acid-binding protein called Pur-alpha, as a component of germ granules in C. elegans We show that PLP-1 is essential for silencing different types of transgenes in the germ line, and for suppressing the expression of several endogenous genes controlled by the germline gene-silencing pathways. Our results reveal that PLP-1 functions downstream of small RNA biogenesis during initiation of gene silencing. Based on these results and the earlier findings that Pur-alpha proteins interact with both RNA and protein, we propose PLP-1 couples certain RNAs with their protein partners in the silencing complex. Its orthologs localized on RNA granules may similarly contribute to germline gene silencing in other organisms.
2020-11-07 | GSE161011 | GEO
Project description:Epigenetic inheritance contributes fundamentally to transgenerational physiology and fitness. Mechanistic understanding of RNA-mediated chromatin modification and transgenerational epigenetic inheritance, which in C. elegans can be triggered by exogenous double-stranded RNA (exo-dsRNA) or facilitated by endogenous small interfering RNAs (endo-siRNAs), has mainly been limited to the post-initiation phases of silencing. Indeed, the dynamic process by which nuclear RNAi engages a transcriptionally active target, before the repressive state is stably established, remains largely a mystery. Here we found that the onset of exo-dsRNA-induced nuclear RNAi is a transgenerational process, and that establishment requires SET-32, one of the three putative histone methyltransferases (HMTs) that are required for H3K9me3 deposition at the nuclear RNAi targets. We also performed multigenerational whole-genome analyses to examine the establishment of silencing at endogenous targets of germline nuclear RNAi. The nuclear Argonaute (AGO) protein HRDE-1 is essential for the maintenance of nuclear RNAi. Repairing a loss-of-function mutation in hrde-1 by CRISPR restored the silencing of endogenous targets in animals carrying wild type set-32. However, for numerous endogenous targets, repairing the hrde-1 mutation in a set-32;hrde-1 double mutant failed to restore their silencing states in up to 20 generations after the hrde-1 repair, using a similar genome editing approach. We found that despite a prominent role in the establishment of silencing, however, set-32 is completely dispensable for the maintenance of silencing once HRDE-1-dependent gene repression is established. Our study indicates that: 1) initiation and maintenance of siRNA-guided transcriptional repression are two distinct processes with different genetic requirements; and 2) the rate-limiting step of the establishment phase is a transgenerational, chromatin-based process. In addition, our study reveals a novel paradigm in which a heterochromatin factor primarily functions to promote the initiation of transgenerational silencing, expanding mechanistic understanding of the well-recognized role of heterochromatin in epigenetic maintenance.
2018-07-26 | GSE117660 | GEO
Project description:Epigenetic inheritance contributes fundamentally to transgenerational physiology and fitness. Mechanistic understanding of RNA-mediated chromatin modification and transgenerational epigenetic inheritance, which in C. elegans can be triggered by exogenous double-stranded RNA (exo-dsRNA) or facilitated by endogenous small interfering RNAs (endo-siRNAs), has mainly been limited to the post-initiation phases of silencing. Indeed, the dynamic process by which nuclear RNAi engages a transcriptionally active target, before the repressive state is stably established, remains largely a mystery. Here we found that the onset of exo-dsRNA-induced nuclear RNAi is a transgenerational process, and that establishment requires SET-32, one of the three putative histone methyltransferases (HMTs) that are required for H3K9me3 deposition at the nuclear RNAi targets. We also performed multigenerational whole-genome analyses to examine the establishment of silencing at endogenous targets of germline nuclear RNAi. The nuclear Argonaute (AGO) protein HRDE-1 is essential for the maintenance of nuclear RNAi. Repairing a loss-of-function mutation in hrde-1 by CRISPR restored the silencing of endogenous targets in animals carrying wild type set-32. However, for numerous endogenous targets, repairing the hrde-1 mutation in a set-32;hrde-1 double mutant failed to restore their silencing states in up to 20 generations after the hrde-1 repair, using a similar genome editing approach. We found that despite a prominent role in the establishment of silencing, however, set-32 is completely dispensable for the maintenance of silencing once HRDE-1-dependent gene repression is established. Our study indicates that: 1) initiation and maintenance of siRNA-guided transcriptional repression are two distinct processes with different genetic requirements; and 2) the rate-limiting step of the establishment phase is a transgenerational, chromatin-based process. In addition, our study reveals a novel paradigm in which a heterochromatin factor primarily functions to promote the initiation of transgenerational silencing, expanding mechanistic understanding of the well-recognized role of heterochromatin in epigenetic maintenance.
2018-07-26 | GSE117659 | GEO
Project description:Epigenetic inheritance contributes fundamentally to transgenerational physiology and fitness. Mechanistic understanding of RNA-mediated chromatin modification and transgenerational epigenetic inheritance, which in C. elegans can be triggered by exogenous double-stranded RNA (exo-dsRNA) or facilitated by endogenous small interfering RNAs (endo-siRNAs), has mainly been limited to the post-initiation phases of silencing. Indeed, the dynamic process by which nuclear RNAi engages a transcriptionally active target, before the repressive state is stably established, remains largely a mystery. Here we found that the onset of exo-dsRNA-induced nuclear RNAi is a transgenerational process, and that establishment requires SET-32, one of the three putative histone methyltransferases (HMTs) that are required for H3K9me3 deposition at the nuclear RNAi targets. We also performed multigenerational whole-genome analyses to examine the establishment of silencing at endogenous targets of germline nuclear RNAi. The nuclear Argonaute (AGO) protein HRDE-1 is essential for the maintenance of nuclear RNAi. Repairing a loss-of-function mutation in hrde-1 by CRISPR restored the silencing of endogenous targets in animals carrying wild type set-32. However, for numerous endogenous targets, repairing the hrde-1 mutation in a set-32;hrde-1 double mutant failed to restore their silencing states in up to 20 generations after the hrde-1 repair, using a similar genome editing approach. We found that despite a prominent role in the establishment of silencing, however, set-32 is completely dispensable for the maintenance of silencing once HRDE-1-dependent gene repression is established. Our study indicates that: 1) initiation and maintenance of siRNA-guided transcriptional repression are two distinct processes with different genetic requirements; and 2) the rate-limiting step of the establishment phase is a transgenerational, chromatin-based process. In addition, our study reveals a novel paradigm in which a heterochromatin factor primarily functions to promote the initiation of transgenerational silencing, expanding mechanistic understanding of the well-recognized role of heterochromatin in epigenetic maintenance.
2018-07-26 | GSE117658 | GEO
Project description:Small RNA sequencing of transgenes silencing by paramutation in C. elegans
| PRJNA276571 | ENA
Project description:piRNAs are required to maintain germline integrity and fertility but their mechanism of action is poorly understood. Here we demonstrate that C. elegans piRNAs silence transcripts in trans through imperfectly complementary sites. We find that target silencing is independent of Piwi endonuclease activity or “slicing”. Instead, we show that piRNAs initiate a localized secondary endogenous small interfering RNA (endo-siRNA) response. Endogenous protein-coding gene, pseudogene and transposon transcripts exhibit Piwi-dependent endo-siRNAs at sites complementary to piRNAs and are derepressed in Piwi mutants. Genomic loci of piRNA biogenesis are depleted of protein-coding genes but not pseudogenes or transposons. Our data suggest that nematode piRNA clusters are evolving to generate piRNAs against active mobile elements. Thus, piRNAs provide heritable, sequence-specific triggers for RNAi in C. elegans. Affymetrix mRNA expression data from wild-type and two independent prg-1;prg-2 double mutant C. elegans strains (mRNA)
2012-06-17 | E-GEOD-37432 | biostudies-arrayexpress