Drosophila Piwi functions downstream of piRNA production mediating a chromatin-based transposon silencing mechanism in female germ line
- 12 December 2011
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 108 (52), 21164-21169
- https://doi.org/10.1073/pnas.1107892109
Abstract
Transposon control is a critical process during reproduction. The PIWI family proteins can play a key role, using a piRNA-mediated slicing mechanism to suppress transposon activity posttranscriptionally. In Drosophila melanogaster, Piwi is predominantly localized in the nucleus and has been implicated in heterochromatin formation. Here, we use female germ-line-specific depletion to study Piwi function. This depletion of Piwi leads to infertility and to axis specification defects in the developing egg chambers; correspondingly, widespread loss of transposon silencing is observed. Germ-line Piwi does not appear to be required for piRNA production. Instead, Piwi requires Aubergine (and presumably secondary piRNA) for proper localization. A subset of transposons that show significant overexpression in germ-line Piwi-depleted ovaries exhibit a corresponding loss of HP1a and H3K9me2. Germ-line HP1a depletion also leads to a loss of transposon silencing, demonstrating the functional requirement for HP1a enrichment at these loci. Considering our results and those of others, we infer that germ-line Piwi functions downstream of piRNA production to promote silencing of some transposons via recruitment of HP1a. Thus, in addition to its better-known function in posttranscriptional silencing, piRNA also appears to function in a targeting mechanism for heterochromatin formation mediated by Piwi.Keywords
This publication has 48 references indexed in Scilit:
- The HP1a Disordered C Terminus and Chromo Shadow Domain Cooperate to Select Target Peptide PartnersChemBioChem, 2011
- An in vivo RNAi assay identifies major genetic and cellular requirements for primary piRNA biogenesis in DrosophilaThe EMBO Journal, 2010
- piRNA-mediated silencing in Drosophila germlinesSeminars in Cell & Developmental Biology, 2010
- Distinct Argonaute-Mediated 22G-RNA Pathways Direct Genome Surveillance in the C. elegans GermlineMolecular Cell, 2009
- The Drosophila HP1 Homolog Rhino Is Required for Transposon Silencing and piRNA Production by Dual-Strand ClustersCell, 2009
- Collapse of Germline piRNAs in the Absence of Argonaute3 Reveals Somatic piRNAs in FliesCell, 2009
- Specialized piRNA Pathways Act in Germline and Somatic Tissues of the Drosophila OvaryCell, 2009
- Conserved themes in small-RNA-mediated transposon controlTrends in Cell Biology, 2008
- A genome-wide transgenic RNAi library for conditional gene inactivation in DrosophilaNature, 2007
- Analysis of Relative Gene Expression Data Using Real-Time Quantitative PCR and the 2−ΔΔCT MethodMethods, 2001