Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Nuclear RNAi Contributes to the Silencing of Off-target Genes and Repetitive Sequences in Caenorhabditis elegans

ABSTRACT: Small RNAs recognize, bind, and regulate other complementary cellular RNAs. The introduction of small RNAs to eukaryotic cells frequently results in unintended silencing of related, but not identical, RNAs: a process termed off-target gene silencing. Off-target gene silencing is one of the major concerns during the application of small RNA-based technologies for gene discovery and the treatment of human disease. Off-target gene silencing is commonly thought to be due to inherent biochemical limitations of the RNAi machinery. Here we show that, following the introduction of exogenous sources of dsRNA, the nuclear RNAi pathway, but not its cytoplasmic counterparts, is the primary source of off-target silencing in C. elegans. In addition, we show that during the normal course of growth and development the nuclear RNAi pathway regulates repetitive gene families. Therefore, we speculate that RNAi off-target effects might not be “mistakes” but, rather, an intentional and genetically programmed aspect of small RNA-mediated gene silencing, which might allow small RNAs to silence rapidly evolving parasitic nucleic acids. Finally, reducing off-target effects by manipulating the nuclear RNAi pathway in vivo might improve the efficacy of small RNA-based technologies. (The Zhou X, Xu F, Mao H, Ji J, Meng Y, Feng X, and Shouhong Guang (2014) Nuclear RNAi Contributes to the Silencing of Off-Target Genes and Repetitive Sequences in Caenorhabditis elegans. Genetics 2014 May;197(1):121-32. doi: 10.1534/genetics.113.159780.)

ORGANISM(S): Caenorhabditis elegans

PROVIDER: GSE92307 | GEO | 2016/12/14

SECONDARY ACCESSION(S): PRJNA357193

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Germ granule association drives small RNA specificity for a nuclear Argonaute protein

Project description:RNA interference (RNAi) is a conserved gene silencing process that exists in diverse organisms to protect genome integrity and regulate gene expression. In C. elegans, the majority of RNAi pathway proteins localize to perinuclear, phase-separated germ granules, which are comprised of sub-domains referred to as P granules, Mutator foci, Z granules, and SIMR foci. However, the protein components and function of the newly discovered SIMR foci are unknown. Here we demonstrate that HRDE-2 localizes to SIMR foci and interacts with the germline nuclear RNAi Argonaute HRDE-1. Furthermore, HRDE-1 also localizes to SIMR foci, dependent on HRDE-2, but only in its small RNA unbound state. This germ granule localization is critical to promote the small RNA binding specificity of HRDE-1 and, in the absence of HRDE-2, HRDE-1 exclusively loads CSR-class 22G-RNAs rather than WAGO-class 22G-RNAs, resulting in H3K9me3 deposition on CSR-target genes. Thus, our study demonstrates that HRDE-2 is critical to ensure that the correct small RNAs are used to guide nuclear RNA silencing in the C. elegans germline.

2023-07-27 | MSV000092546 | MassIVE

The activity of the Caenorhabditis elegans Aquarius helicase EMB-4 enables the nuclear RNAi machinery to engage nascent RNA

Project description:Germline small RNA pathways initiate silencing of repetitive elements in animals and an interplay of nuclear small RNAs and chromatin modifications maintain this silencing, protecting the germline from spreading of transposable elements. In C. elegans germline, nuclear argonaute protein HRDE-1 initiates the transcriptional silencing pathway that is crucial for long term and heritable silencing of genes and repetitive regions. Here, we show that HRDE-1 interacts with components of the splicing machinery and the exon-junction complex. One such factor is the conserved RNA helicase EMB-4/AQR that binds introns and recruits the exon-junction proteins to newly spliced RNA. Our data shows that EMB-4/AQR is required for the transcriptional silencing pathway initiated by HRDE-1 and it functions by removing the intronic barriers to silencing thorugh its helicase function.

2017-06-30 | PXD004416 | Pride

Small RNA sequencing of transgenes silencing by paramutation in C. elegans

Project description:In the nematode Caenorhabditis elegans, different small RNA-dependent gene silencing mechanisms act in the germline to initiate transgenerational gene silencing. Piwi-interacting RNAs (piRNAs) can initiate transposon and gene silencing by acting upstream of endogenous short interfering RNAs (siRNAs), which engage a nuclear RNA interference (RNAi) pathway to trigger transcriptional gene silencing. Once gene silencing has been established, it can be stably maintained over multiple generations without the requirement of the initial trigger and is also referred to as RNAe or paramutation. This heritable silencing depends on the integrity of the nuclear RNAi pathway. However, the exact mechanism by which silencing is maintained across generations is not understood.Here we demonstrate that silencing of piRNA targets involves the production of two distinct classes of small RNAs with different genetic requirements. The first class, secondary siRNAs, are localized close to the direct target site for piRNAs. Nuclear import of the secondary siRNAs by the Argonaute HRDE-1 leads to the production of a distinct class of small RNAs that map throughout the transcript, which we term tertiary siRNAs. Both classes of small RNAs are necessary for full repression of the target gene and can be maintained independently of the initial piRNA trigger. Consistently, we observed a form of paramutation associated with tertiary siRNAs. Once paramutated, a tertiary siRNA generating allele confers dominant silencing in the progeny regardless of its own transmission, suggesting germline-transmitted siRNAs are sufficient for multigenerational silencing. C. elegans strains containing transgenes silenced by piRNAs were crossed to strains with transgenes with similar sequences but without piRNA target sites, to investigate the spreading of silencing between transgenes mediated by small RNAs. Mutant backgrounds were used to investigate the genetic requirements for this process.

2015-04-01 | E-GEOD-66344 | biostudies-arrayexpress

Small RNA sequencing of transgenes silencing by paramutation in C. elegans

2015-04-01 | GSE66344 | GEO

The dimeric SFiNX complex enables piRNA-guided co-transcriptional silencing through molecular condensate formation

Project description:Nuclear Argonaute proteins, guided by their bound small RNAs, orchestrate heterochromatin formation at transposon insertions and repetitive genomic loci. The molecular mechanisms that, besides recruiting heterochromatin effector proteins, are required for this silencing process are poorly understood. Here, we show that the SFiNX complex, the central silencing mediator downstream of nuclear Piwi-piRNA complexes in Drosophila, enables co-transcriptional silencing via the formation of molecular condensates. Condensate formation is stimulated by nucleic acid binding and requires SFiNX to form a homodimer. The dynein light chain dLC8, a highly conserved dimerization hub protein, mediates homo-dimerization of SFiNX. Point mutations preventing dLC8-mediated SFiNX dimerization result in transposon de-repression and sterility. dLC8’s function can be bypassed with a heterologous dimerization domain, suggesting that dimerization is a constitutive rather than a regulated feature of SFiNX. We propose that nucleic-acid stimulated condensate formation enables co-transcriptional silencing through the retention of the target RNA at chromatin, thereby allowing effector proteins to establish heterochromatin at the target locus.

2021-02-12 | PXD022010 | Pride

A small RNA mechanism distinct from the RNAi and microRNA pathways silences selfish genetic elements in Drosophila.

Project description:In flies, repeat-associated small interfering RNAs (rasiRNAs) ensure genomic stability by silencing endogenous selfish genetic elements such as retrotransposons and repetitive sequences. Here, we show that while small interfering RNAs (siRNAs) derive from both the sense and antisense strands of their double-stranded RNA precursors, rasiRNAs arise mainly from the antisense strand. rasiRNA production appear not to require Dicer-1, which makes microRNAs, or Dicer-2, which makes siRNAs, and rasiRNAs lack the 2´,3´ hydroxy termini characteristic of animal siRNA and miRNA. Unlike siRNAs and miRNAs, rasiRNAs function through the Piwi, rather than the Ago, Argonaute protein subfamily. Thus, rasiRNAs define a third RNA silencing pathway distinct from both the miRNA and RNAi pathways. Keywords: gene silencing; post-transcriptional gene regulation; short RNAs; RNAi; rasiRNAs; rasiRNA; microRNAs; microRNA; siRNAs; siRNA

2006-06-30 | GSE4932 | GEO

Germ granule association drives small RNA specificity for a nuclear Argonaute protein [sRNA-seq]

Project description:RNA interference (RNAi) is a conserved gene silencing process that exists in diverse organisms to protect genome integrity and regulate gene expression. In C. elegans, majority of RNAi components are located in phase-separated perinuclear germ granules, including P granule, Mutator foci, Z granule, and SIMR foci. However, the protein components and function of the newly discovered SIMR foci are unknown. Here we identified HRDE-2 as a SIMR foci component, which interacts with the germline nuclear RNAi Argonaute HRDE-1. We found that unloaded HRDE-1 localizes to SIMR foci and this localization depends on HRDE-2. In addition, HRDE-2 contributes to HRDE-1 small RNAs binding specificity and, in the absence of HRDE-2, HRDE-1 exclusively loads CSR-class 22G-RNAs rather than WAGO-class 22G-RNAs, promotes H3K9me3 deposition on CSR-targets, but does not silence these CSR-target genes. Thus, our study demonstrates that HRDE-2 is critical to ensure correct small RNAs are used to guide nuclear RNA silencing in the C. elegans germline.

2023-08-01 | GSE239289 | GEO

Germ granule association drives small RNA specificity for a nuclear Argonaute protein [mRNA-seq]

Project description:RNA interference (RNAi) is a conserved gene silencing process that exists in diverse organisms to protect genome integrity and regulate gene expression. In C. elegans, majority of RNAi components are located in phase-separated perinuclear germ granules, including P granule, Mutator foci, Z granule, and SIMR foci. However, the protein components and function of the newly discovered SIMR foci are unknown. Here we identified HRDE-2 as a SIMR foci component, which interacts with the germline nuclear RNAi Argonaute HRDE-1. We found that unloaded HRDE-1 localizes to SIMR foci and this localization depends on HRDE-2. In addition, HRDE-2 contributes to HRDE-1 small RNAs binding specificity and, in the absence of HRDE-2, HRDE-1 exclusively loads CSR-class 22G-RNAs rather than WAGO-class 22G-RNAs, promotes H3K9me3 deposition on CSR-targets, but does not silence these CSR-target genes. Thus, our study demonstrates that HRDE-2 is critical to ensure correct small RNAs are used to guide nuclear RNA silencing in the C. elegans germline.

2023-08-01 | GSE239286 | GEO

Germ granule association drives small RNA specificity for a nuclear Argonaute protein [CUT&Tag]

Project description:RNA interference (RNAi) is a conserved gene silencing process that exists in diverse organisms to protect genome integrity and regulate gene expression. In C. elegans, majority of RNAi components are located in phase-separated perinuclear germ granules, including P granule, Mutator foci, Z granule, and SIMR foci. However, the protein components and function of the newly discovered SIMR foci are unknown. Here we identified HRDE-2 as a SIMR foci component, which interacts with the germline nuclear RNAi Argonaute HRDE-1. We found that unloaded HRDE-1 localizes to SIMR foci and this localization depends on HRDE-2. In addition, HRDE-2 contributes to HRDE-1 small RNAs binding specificity and, in the absence of HRDE-2, HRDE-1 exclusively loads CSR-class 22G-RNAs rather than WAGO-class 22G-RNAs, promotes H3K9me3 deposition on CSR-targets, but does not silence these CSR-target genes. Thus, our study demonstrates that HRDE-2 is critical to ensure correct small RNAs are used to guide nuclear RNA silencing in the C. elegans germline.

2023-08-01 | GSE239285 | GEO

Ribozyme-enhanced single-stranded Ago2-processed interfering RNA triggers efficient gene silencing with fewer off-target effects.

Project description:RNA interference (RNAi) is an evolutionarily conserved phenomenon of post-transcriptional gene silencing mediated by small interfering RNAs (siRNAs) generated from short hairpin RNAs (shRNAs) by Dicer cleavage. Here, we report that siRNA precursors can be divided into two categories with different processing mechanisms and silencing activities that are dependent on stem loop length. We designed an alternative siRNA precursor for triggering RNAi named single-stranded Argonaute2 (Ago2)-processed interfering RNA (saiRNA). saiRNA is composed of a 16-18 bp stem and a loop complementary to the target transcript. The introduction of a self-cleavage ribozyme derived from hepatitis delta virus (HDV) to the 3’ end of the saiRNA dramatically improved its silencing activity. Unlike classical shRNA, the strand-specific cleavage of saiRNA by Ago2 during its processing not only eliminated the passenger strand but also avoided the association of mature siRNA with non-nucleolytic Ago proteins, thereby further reducing the risk of off-target effects. Additionally, saiRNA exhibited less competition with the biogenesis of endogenous miRNAs. Therefore, HDV ribozyme-enhanced saiRNA provides a reliable tool for RNAi applications.

2015-06-01 | GSE68631 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data