Multiple roles for Piwi in silencing Drosophila transposons

Rozhkov, N. V., Hammell, M., Hannon, G. J. (2013) Multiple roles for Piwi in silencing Drosophila transposons. Genes and Development, 27 (4). pp. 400-412. ISSN 08909369 (ISSN)

URL: http://www.ncbi.nlm.nih.gov/pubmed/23392609
DOI: 10.1101/gad.209767.112

Abstract

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 germcell 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 typespecific 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. © 2013 by Cold Spring Harbor Laboratory Press.

Item Type: Paper
Uncontrolled Keywords: Drosophila Nascent piRNA Steady state Transposon
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
organism description > animal > insect > Drosophila
bioinformatics > genomics and proteomics > genetics & nucleic acid processing
bioinformatics > genomics and proteomics
organism description > animal
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > piRNA
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > transposons
CSHL Authors:
Communities: CSHL Post Doctoral Fellows
CSHL labs > Hammell M. lab
CSHL labs > Hannon lab
CSHL Cancer Center Shared Resources > Bioinformatics Service
CSHL Cancer Center Shared Resources > DNA Sequencing Service
Depositing User: Matt Covey
Date Deposited: 01 Apr 2013 14:51
Last Modified: 26 Dec 2014 16:47
PMCID: PMC3589557
Related URLs:
URI: http://repository.cshl.edu/id/eprint/28056

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