Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Slicing-Independent RISC Activation Requires the Argonaute PAZ Domain

ABSTRACT: Small RNAs regulate the genetic networks through a ribonucleoprotein complex called the RNA induced silencing complexes (RISC), which in mammals contains at its center one of four Argonaute proteins (Ago1-4). A key regulatory event in the RNAi and miRNA pathways is Ago loading, where double stranded small RNA duplexes are incorporated into RISC (pre-RISC) and then become single stranded (mature-RISC), a process that is not well understood. The Agos contain an evolutionary conserved PAZ (Piwi/Argonaute/Zwille) domain whose primary function is to bind the 3’-end of small RNAs. We created multiple Paz domain disrupted Ago mutant proteins and studied their biochemical properties and biological functionality in cells. We found that the Paz domain is dispensable for Ago loading of slicing-competent RISC. In contrast, in the absence of slicer activity or slicer substrate duplex RNAs, Paz-disrupted Agos bound duplex siRNAs but were unable to unwind/eject the passenger strand and form functional RISC complexes. We have discovered that the highly conserved Paz domain plays an important role in RISC activation, providing new mechanistic insights into how miRNAs regulate genes, as well as new insights for future design of miRNA and RNAi-based therapeutics.

ORGANISM(S): Homo sapiens

PROVIDER: GSE39146 | GEO | 2012/07/12

SECONDARY ACCESSION(S): PRJNA170090

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

Slicing-Independent RISC Activation Requires the Argonaute PAZ Domain

Project description:Small RNAs regulate the genetic networks through a ribonucleoprotein complex called the RNA induced silencing complexes (RISC), which in mammals contains at its center one of four Argonaute proteins (Ago1-4). A key regulatory event in the RNAi and miRNA pathways is Ago loading, where double stranded small RNA duplexes are incorporated into RISC (pre-RISC) and then become single stranded (mature-RISC), a process that is not well understood. The Agos contain an evolutionary conserved PAZ (Piwi/Argonaute/Zwille) domain whose primary function is to bind the 3’-end of small RNAs. We created multiple Paz domain disrupted Ago mutant proteins and studied their biochemical properties and biological functionality in cells. We found that the Paz domain is dispensable for Ago loading of slicing-competent RISC. In contrast, in the absence of slicer activity or slicer substrate duplex RNAs, Paz-disrupted Agos bound duplex siRNAs but were unable to unwind/eject the passenger strand and form functional RISC complexes. We have discovered that the highly conserved Paz domain plays an important role in RISC activation, providing new mechanistic insights into how miRNAs regulate genes, as well as new insights for future design of miRNA and RNAi-based therapeutics. Various Argonautes associated small RNA profiles were generated by deep sequencing the Agos-IP samples in HEK293 Cells transfected with corresponding Argonaute.

2012-07-12 | E-GEOD-39146 | biostudies-arrayexpress

Distinct Functions of Argonaute Slicer in siRNA Maturation and Heterochromatin Formation

Project description:Small-RNA (sRNA)-guided transcriptional gene silencing by Argonaute (Ago)-containing complexes is fundamental to genome integrity and epigenetic inheritance. The RNA cleavage (“Slicer”) activity of Argonaute has been implicated in both sRNA maturation and target RNA cleavage. Typically, Argonaute slices and releases the passenger strand of duplex sRNA to generate active silencing complexes, but it remains unclear whether slicing of target nascent RNAs, or other RNAi components, also contributes to downstream transcriptional silencing. Here, we develop a strategy for loading the fission yeast Ago1 with a single-stranded sRNA guide, which bypasses the requirement for slicer activity in generation of active silencing complexes. We show that slicer-defective Ago1 can mediate secondary sRNA generation, H3K9 methylation, and silencing similar to or better than wild-type and associates with chromatin more efficiently. The results define an ancient and minimal sRNA-mediated chromatin silencing mechanism, which resembles the germline-specific sRNA-dependent transcriptional silencing pathways in Drosophila and mammals. This SuperSeries is composed of the SubSeries listed below.

2016-12-19 | GSE81734 | GEO

Identifying mRNA Sequence Elements for Target Recognition by Human Argonaute Proteins

Project description:It is commonly known that mammalian microRNAs guide the RNA-induced silencing complex (RISC) to target mRNAs through the seed-pairing rule. However, recent experiments by co-immunoprecipitating the argonaute proteins (AGOs), the central catalytic component of RISC, have consistently revealed extensive AGO-associated mRNAs lacking seed complementarity with microRNAs. We herein test the hypothesis that AGO has its own binding preference within target mRNAs, independent of guide microRNAs. By systematically analyzing the data from in vivo cross-linking experiments with human AGOs, we have identified a structurally accessible and evolutionarily conserved region (~10 nucleotides) that alone can accurately predict AGO-mRNA associations, independent of the presence of microRNA binding sites. Within this region, we further identified an enriched motif that is also consistently present in several independent AGO-immunoprecipitation datasets. We used RNAcompete to enumerate the RNA-binding preference of human AGO2 to all possible 7-mer RNA sequences, and validated our motif in vitro. These findings reveal a novel function of AGOs as sequence-specific RNA-binding proteins, which may aid microRNAs in recognizing their targets with high specificity. Here, we analyze the RNA-binding preference of human Argonaute 2 protein using RNAcompete assay

2014-02-19 | E-GEOD-55122 | biostudies-arrayexpress

The structure of human Argonaute-2 in complex with miR-20a

Project description:Argonaute proteins lie at the heart of the RNA-Induced Silencing Complex (RISC), wherein they use small RNA guides to recognize targets. Some Argonaute proteins can directly cleave their targets, whereas others recruit co-factors to repress independently of “slicing.” Prior studies established the architecture of Argonaute proteins; however, we have not yet had a detailed picture of an Argonaute whose biochemical and biological functions were well established. Here we describe the crystal structure of human Argonaute-2 bound to miR-20a at 2.2 Å resolution. Overall architecture and domain organization is shared with its prokaryotic counterparts, though Ago2 is somewhat more open, with its PAZ domain further removed from the other domains. The miRNA is anchored at both ends by the Mid and PAZ domains but makes several kinks and turns along the binding groove. The RNA confers remarkable stability on the Argonaute protein, locking this otherwise flexible enzyme into a stable conformation. total small RNAs (19-29nt) and small RNAs associated with purified hArgonaute2 purified from SF9 cells. These were processed and sequenced on Illumina GA-II platform.

2012-05-12 | E-GEOD-37931 | biostudies-arrayexpress

Homo sapiens

Project description:Slicing-Independent RISC Activation Requires the Argonaute PAZ Domain

| PRJNA170090 | ENA

The Vasa homolog RDE-12 engages target mRNA and a secondary-Argonaute WAGO-1 to promote RNAi in C. elegans

Project description:Argonaute proteins (AGOs) are key nuclease effectors of RNA interference (RNAi) [1]. Although purified AGOs can mediate a single round of target-RNA cleavage in vitro, accessory factors are required for siRNA loading and to achieve multiple-target turnover [2, 3]. To identify AGO co-factors we immunoprecipitated the C. elegans AGO WAGO-1, which engages amplified small RNAs during RNAi [4]. These studies identified a robust association between WAGO-1 and a conserved Vasa ATPase-related protein RDE-12. rde-12 mutants are deficient in RNAi including viral suppression, and fail to produce amplified secondary siRNAs and certain endogenous siRNAs (endo-siRNAs). RDE-12 co-localizes with WAGO-1 in germline P-granules and to peri-nuclear cytoplasmic foci in somatic cells. These findings and our genetic studies suggest that (i) RDE-12 is first recruited to target mRNAs by upstream AGOs (RDE-1 and ERGO-1) where it promotes small-RNA amplification and/or WAGO-1 loading, and that (ii) downstream of these events, RDE-12 forms an RNase-resistant (target mRNA-independent) complex with WAGO-1 that may scan for additional target mRNAs. Examine small RNA population changes in rde-12 mutants

2014-06-24 | E-GEOD-54396 | biostudies-arrayexpress

small RNA sequences from grafted Arabidopsis thaliana expressing SucSUL inverted repeat

Project description:We aimed at characterizing the identity of the silencing signal i.e. siRNA or longer dsRNA precursor thereof. We used transgenic dsRNA, endogenous dsRNA or virus infection as sources of siRNAs combined to sophisticated immunoprecipitation-based procedures coupled to deep-sequencing. We found that siRNAs populations are highly similar between incipient and recipient cells in the three systems. Additionally, a significant depletion of 5’U and 5’A content in the recipient cells suggested Argonaute-loading dependent depletion of these siRNAs during their movement over multiple cell layers. Using the PAZ-domain mutants ago1-18 and ago1-42 confirmed that the observed depletion of mobile siRNAs is the result of RISC loading. The results advocate movement of individual siRNA duplexes as opposed to their precursors and that loading into Argonaut proteins renders those small RNAs cell-autonomous.

2020-04-06 | GSE112885 | GEO

Movement of Arabidopsis thaliana inverted repeat small RNA between leaves vascular and epidermis tissues

2020-04-06 | GSE112929 | GEO

Identifying mRNA Sequence Elements for Target Recognition by Human Argonaute Proteins

2014-02-19 | GSE55122 | GEO

Detection of siRNA movement in Arabidopsis thaliana using P19 under root cell layer specific expression

Project description:We aimed at characterizing the identity of the silencing signal i.e. siRNA or longer dsRNA precursor thereof. We used transgenic dsRNA, endogenous dsRNA or virus infection as sources of siRNAs combined to sophisticated immunoprecipitation-based procedures coupled to deep-sequencing. We found that although they are diluted as they move away from their sites of production, siRNAs population are highly similar between incipient and recipient cells in the three systems. Additionally, a significant depletion of 5’U and 5’A content in the recipient cells suggested Argonaute-loading dependent depletion of these siRNAs during their movement over multiple cell layers. Using the PAZ-domain mutants ago1-18 and ago1-42 confirmed that the observed depletion of mobile siRNAs is the result of RISC loading. The results advocate movement of individual siRNA duplexes as opposed to their precursors and that loading into Argonaut proteins renders those small RNAs cell-autonomous.

2020-04-06 | GSE113029 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

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