Browse
Submit Data
Databases
API
Help

Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

58 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Probing the initiation and effector phases of the somatic piRNA pathway in Drosophila

ABSTRACT: Combining RNAi in cultured cells and analysis of mutant animals, we probed roles of known piRNA pathway components in the initiation and effector phases of transposon silencing. total RNA and RNA associated with Piwi was isolated and size-fractionated by PAGE into 19-29nt. These were processed and sequenced on Illumina Genome Analyzer II.

ORGANISM(S): Drosophila melanogaster

SUBMITTER: Astrid Haase

PROVIDER: E-GEOD-24108 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Json Xml

Publications

Probing the initiation and effector phases of the somatic piRNA pathway in Drosophila.

Haase Astrid D AD Fenoglio Silvia S Muerdter Felix F Guzzardo Paloma M PM Czech Benjamin B Pappin Darryl J DJ Chen Caifu C Gordon Assaf A Hannon Gregory J GJ

Genes & development 20101021 22

Combining RNAi in cultured cells and analysis of mutant animals, we probed the roles of known Piwi-interacting RNA (piRNA) pathway components in the initiation and effector phases of transposon silencing. Squash associated physically with Piwi, and reductions in its expression led to modest transposon derepression without effects on piRNAs, consistent with an effector role. Alterations in Zucchini or Armitage reduced both Piwi protein and piRNAs, indicating functions in the formation of a stable ...[more]

PMID: 20966049

Similar Datasets

Production of artificial piRNAs in flies and mice

Project description:In animals, a discrete class of small RNAs, the piwi-interacting RNAs (piRNAs), guard germ cell genomes against the activity of mobile genetic elements. piRNAs are generated, via an unknown mechanism, from apparently single-stranded precursors that arise from discrete genomic loci, termed piRNA clusters. The content of piRNA clusters, determines the capacity of the system to respond to a given element, in essence comprising an organism's evolving molecular definition of transposons. Presently, little is known about the signals that distinguish a locus as a source of piRNAs and about how abundant piRNAs are selected. To address these questions, we inserted new sequence information into piRNA clusters in mice and flies. In all cases, this information was incorporated into the piRNA repertoire and in one instance was shown to confer the ability to recognize and silence a corresponding element. Notably, patterns of piRNA abundance suggested that both intrinsic sequence and context with the cluster inform piRNA generation. Though piRNAs themselves are not conserved between species, the genomic location of clusters is often retained. We were able to create artificial piRNA clusters in non-native contexts in both mice and flies, indicating that the signals that define these as generative loci must lie within the clusters themselves rather than being implicit in their genomic position. Total RNA and RNA associated with Piwi proteins were isolated and size-fractionated by PAGE into 19-33nt. These were processed and sequenced on the Illumina GA2 platform.

2012-01-01 | E-GEOD-32435 | biostudies-arrayexpress

FLX sequencing of Piwi-associated small RNAs extracted from Drosophila ovarian somatic cells (OSC)

Project description:piRNAs function in silencing retrotransposons by associating with the PIWI proteins, AGO3, Aub, and Piwi, in Drosophila germlines. Bioinformatics analyses of piRNAs in Drosophila ovaries suggested that piRNAs are produced by two systems, the primary processing pathway and the amplification loop, from repetitive genes and piRNA clusters in the genome. The amplification loop occurs in a Dicer-independent, PIWI-Slicer-dependent manner. However, the primary processing pathway remains largely conceptual. Here we show that in ovarian somatic cells, which lack Aub and AGO3 but express Piwi, the primary processing pathway for piRNAs indeed exists. Keywords: Small RNA profiling by high throughput sequencing Piwi-associated small RNAs were extracted from Drosophila ovarian somatic cells and their deep sequencing was carried out.

2009-10-01 | E-GEOD-15137 | biostudies-arrayexpress

The Function of Piwi is Independent of Its Slicer Activity

Project description:In diverse organisms, the highly-conserved Piwi proteins bind to a complex class of small non-coding RNAs called piRNAs, and are essential for germline stem cell maintenance, transposon silencing, fertility, and offspring viability1. By homology with other Argonautes, Piwi proteins have been proposed and later reported to possess endonuclease activity in vitro, effected by its conserved aspartate catalytic triad2,3. Indeed, mutation of these residues in one of the three mouse PIWI proteins, MILI, affects the production of Line 1 piRNAs and spermatogenesis4. In Drosophila, the conserved slicer function has been proposed to be crucial for all Piwi proteins in piRNA amplification and transposon silencing5. Here, we report in vivo evidence that, in contrast to common belief, the catalytic triad of Piwi is not required for the function of PIwi in the germline for stem cell maintenance, fertility, transposon silencing, or piRNA biogenesis. In addition, it is not required for piRNA biogenesis in the soma where Piwi is the sole Piwi-subfamily protein involved in the process. These observations, together with the recent findings on MILI and MIWI2 triad mutant, indicate that even though the slicer function may be required for a subset of piRNA-mediated process, it is overall inconsequential for the function of Piwi proteins Assess the role of the endonuclease activity of Piwi in all known biological processes that involve Piwi function in Drosophila ovary

2013-02-04 | E-GEOD-34032 | biostudies-arrayexpress

RNA elements in precursors instruct directional and processive primary piRNA biogenesis

Project description:PIWI-interacting RNAs (piRNAs) are animal gonad-specific small RNAs that control the activity of transposable elements. Long single stranded RNAs from a variety of sources are substrates for the nebulous primary processing pathway that converts these into thousands of 24-30 nucleotide (nt) piRNAs. How these transcripts are selected as precursors is not known. Here we show that targeting a transcript with PIWI slicer activity of cysosolic Ago3 is sufficient to trigger ~30-nt waves of non-overlapping primary piRNAs in the fly ovarian germline. The generated primary piRNAs are almost exclusively loaded into the nuclear PIWI protein, Piwi. In the fly ovarian somatic environment we find that an RNA fragment from the 5? end of a piRNA cluster is able to direct a heterologous sequence into primary processing. This piRNA trigger sequence (PTS) element drives generation of overlapping piRNAs from the transcript. Both mechanisms proceed with general 5?-3? directionality. We propose that the former pathway serves to link cytoplasmic silencing of a target to nuclear transcriptional repression, while the latter extracts silencing information from a wide variety of genomic sources including piRNA clusters, select protein coding and transposon transcripts. Total or immunoprecipitated small RNAs were purified from transfected BmN4 cells, Drosophila ovarian somatic cells (OSC) and from fly ovaries and high-throughput sequencing libraries were prepared. The mouse testicular RNAs were purified after ribozero treatment.

2015-07-09 | E-GEOD-69102 | biostudies-arrayexpress

Transcriptome and transposable element dynamics during PIWI regulation in Drosophila ovarian cell cultures

Project description:This study examines the regulatory capacity of the Piwi protein in the Drosophila OSS cell. Piwi CLIP-Seq, mRNA-Seq and nascent RNAseq datasets were integrated to determine how Piwi proteins where using piRNAs and binding interactions to regulate the expression of transcripts. We also sequenced the genomes of various OSS cell lines. We first performed several replicates of a Piw CLIP-Seq experiment to isolate RNA fragments as CLIP-tags to discover which transcripts are preferentially bound by the Piwi protein. Then we performed several types of mRNA expression profiling experiments using several forms of mRNA-Seq library construction formats. Finally, we sequenced the genomes from various OSS cell lines. The genomic sequencing component of the study is represented by BioProject PRJNA240323. The genomic sequencing raw data have been deposited at SRA (SRP039565).

2014-09-15 | E-GEOD-45112 | biostudies-arrayexpress

piRNA libraries from Drosophila melanogaster ovaries

Project description:Drosophila Piwi-family proteins have been implicated in transposon control. Here, we examine piwi-interacting RNAs (piRNAs) associated with each Drosophila Piwi protein and find that Piwi and Aubergine bind RNAs that are predominantly antisense to transposons, whereas Ago3 complexes contain predominantly sense piRNAs. As in mammals, the majority of Drosophila piRNAs are derived from discrete genomic loci. These loci comprise mainly defective transposon sequences, and some have previously been identified as master regulators of transposon activity. Our data suggest that heterochromatic piRNA loci interact with potentially active, euchromatic transposons to form an adaptive system for transposon control. Complementary relationships between sense and antisense piRNA populations suggest an amplification loop wherein each piRNA-directed cleavage event generates the 5’ end of a new piRNA. Thus, sense piRNAs, formed following cleavage of transposon mRNAs, may enhance production of antisense piRNAs, complementary to active elements, by directing cleavage of transcripts from master control loci. Keywords: small RNA libraries from Drosophila ovaries small RNAs (23-29nt) were isolated from total ovarian RNA or from immunopreciptated Piwi/Aubergine/Ago3 complexes. cDNA libraries were constructed after Pfeffer et al. 2005 (Nat. Methods) and sequenced at 454 Life Sciences. The used strain is OregonR. Only sequences matching the Release5 genome assembly (www.fruitfly.org) are considered.

2007-03-08 | E-GEOD-6734 | biostudies-arrayexpress

Characterization of active piRNAs and an piRNA machinery in WRR-1 cells deficient for the Hippo pathway (deficient for the warts tumor suppressor) and expressing activated RasV12 (small RNA)

Project description:We have found that oncogenic Ras combined with loss of the Hippo tumour-suppressor pathway reactivates a primary piRNA pathway in Drosophila somatic cells, coincident with oncogenic transformation. In these cells, Piwi becomes loaded with piRNAs derived from generative loci, which are normally restricted to either the germline or the somatic follicle cells. Negating the pathway leads to increases in the expression of a wide variety of transposons and also to altered expression of some protein coding genes. This correlates with a reduction in the proliferation of the transformed cells in culture, suggesting that at least in this context, the piRNA pathway may play a functional role in cancer. Small RNAs cloned from whole cells, piwi-bound small RNAs and long RNA-Seq were performed in wts-RNAi;RasV12 cells to identify piRNAs and gene expression and compared to RasV12 cells, somatic OSS cells, and germline UAS-wts-RNAi;UAS-RasV12 control ovaries. After knock-down of several components of the piRNA machinery in WRR-1 cells (piwi, zuchini, armitage, aubergine, argonaute3) and GFP and/or dsRED control knock-downs, small RNAs were cloned and gene expression profiles (RNA-Seq) were established.

2016-08-01 | E-GEOD-83871 | biostudies-arrayexpress

Krimper enforces an antisense bias on piRNA pools by binding AGO3 in the Drosophila germline

Project description:Piwi-interacting RNAs (piRNAs) suppress transposon activity in animal germ cells. In the Drosophila ovary, primary Aubergine (Aub)-bound antisense piRNAs initiate the ping-pong cycle to produce secondary AGO3-bound sense piRNAs. This increases the number of secondary Aub-bound antisense piRNAs that can act to destroy transposon mRNAs. Here we show that Krimper (Krimp), a Tudor-domain protein, directly interacts with piRNA-free AGO3 to promote symmetrical dimethylarginine (sDMA) modification, ensuring sense piRNA-loading onto sDMA-modified AGO3. In aub mutant ovaries, AGO3 associates with ping-pong signature piRNAs, suggesting AGO3’s compatibility with primary piRNA loading. Krimp sequesters ectopically expressed AGO3 within Krimp bodies in cultured ovarian somatic cells (OSCs), in which only the primary piRNA pathway operates. Upon krimp-RNAi in OSCs, AGO3 loads with piRNAs, further showing the capacity of AGO3 for primary piRNA loading. We propose that Krimp enforces an antisense bias on piRNA pools by binding AGO3 and blocking its access to primary piRNAs. In order to investigate function of Krimp in piRNA pathway, sequencing of Piwi subfamily protein associated small RNAs was performed using adult Drosophila ovaries and Ovarian Somatic Cells (OSCs) depleted for Krimp or Aub.

2015-05-28 | E-GEOD-69293 | biostudies-arrayexpress

A genome-wide RNAi screen draws a genetic framework for transposon control and primary piRNA biogenesis in Drosophila

Project description:A large fraction of our genome consists of mobile genetic elements. Governing transposons in germ cells is critically important, and failure to do so compromises genome integrity, leading to sterility. In animals, the piRNA pathway is the key to transposon constraint, yet the precise molecular details of how piRNAs are formed and how the pathway represses mobile elements remain poorly understood. In an effort to identify general requirements for transposon control and novel components of the piRNA pathway, we carried out a genome-wide RNAi screen in Drosophila ovarian somatic sheet cells. We identified and validated 87 genes necessary for transposon silencing. Among these were several novel piRNA biogenesis factors. We also found CG3893 (asterix) to be essential for transposon silencing, most likely by contributing to the effector step of transcriptional repression. Asterix loss leads to decreases in H3K9me3 marks on certain transposons but has no effect on piRNA levels. We sequenced small RNAs, RNA-seq and ChIP-seq from either tj-Gal4 driven hpRNA knockdown flies or P-element insertion flies

2013-05-09 | E-GEOD-46009 | biostudies-arrayexpress

Interactome analysis of Aedes aegypti PIWI proteins

Project description:PIWI-interacting (pi) RNAs are a class of small RNAs that have diverse functions in mosquitoes. In order to uncover novel components involved in biogenesis or function of the piRNA pathway in Aedes aegypti mosquitoes, we performed mass spectrometry analyses on immunoprecipitated PIWI proteins and their interactors.

2021-04-28 | PXD021382 | Pride

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