Document Detail

Multiple roles for Piwi in silencing Drosophila transposons.
MedLine Citation:
PMID:  23392609     Owner:  NLM     Status:  MEDLINE    
Silencing of transposons in the Drosophila ovary relies on three Piwi family proteins--Piwi, Aubergine (Aub), and Ago3--acting in concert with their small RNA guides, the Piwi-interacting RNAs (piRNAs). Aub and Ago3 are found in the germ cell cytoplasm, where they function in the ping-pong cycle to consume transposon mRNAs. The nuclear Piwi protein is required for transposon silencing in both germ and somatic follicle cells, yet the precise mechanisms by which Piwi acts remain largely unclear. We investigated the role of Piwi by combining cell type-specific knockdowns with measurements of steady-state transposon mRNA levels, nascent RNA synthesis, chromatin state, and small RNA abundance. In somatic cells, Piwi loss led to concerted effects on nascent transcripts and transposon mRNAs, indicating that Piwi acts through transcriptional gene silencing (TGS). In germ cells, Piwi loss showed disproportionate impacts on steady-state RNA levels, indicating that it also exerts an effect on post-transcriptional gene silencing (PTGS). Piwi knockdown affected levels of germ cell piRNAs presumably bound to Aub and Ago3, perhaps explaining its post-transcriptional impacts. Overall, our results indicate that Piwi plays multiple roles in the piRNA pathway, in part enforcing transposon repression through effects on local chromatin states and transcription but also participating in germ cell piRNA biogenesis.
Nikolay V Rozhkov; Molly Hammell; Gregory J Hannon
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2013-02-07
Journal Detail:
Title:  Genes & development     Volume:  27     ISSN:  1549-5477     ISO Abbreviation:  Genes Dev.     Publication Date:  2013 Feb 
Date Detail:
Created Date:  2013-02-22     Completed Date:  2013-04-09     Revised Date:  2014-06-30    
Medline Journal Info:
Nlm Unique ID:  8711660     Medline TA:  Genes Dev     Country:  United States    
Other Details:
Languages:  eng     Pagination:  400-12     Citation Subset:  IM    
Data Bank Information
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MeSH Terms
Argonaute Proteins / genetics*,  metabolism
DNA Transposable Elements / genetics*
Drosophila Proteins / genetics*,  metabolism
Drosophila melanogaster / genetics*,  metabolism*
Gene Knockdown Techniques
Ovary / metabolism
Peptide Initiation Factors / genetics,  metabolism
RNA Interference*
RNA, Small Interfering / genetics,  metabolism
Grant Support
P30 CA045508/CA/NCI NIH HHS; R37 GM062534/GM/NIGMS NIH HHS; //Howard Hughes Medical Institute
Reg. No./Substance:
0/AGO3 protein, Drosophila; 0/Argonaute Proteins; 0/DNA Transposable Elements; 0/Drosophila Proteins; 0/Peptide Initiation Factors; 0/RNA, Small Interfering; 0/aubergine protein, Drosophila; 0/piwi protein, Drosophila
Comment In:
Curr Biol. 2013 Apr 22;23(8):R318-20   [PMID:  23618667 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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