Multiple roles for Piwi in silencing Drosophila transposons

摘要: Silencing of transposons in the Drosophila ovary relies on three Piwi family proteins—Piwi, Aubergine (Aub), and Ago3—acting concert with their small RNA guides, Piwi-interacting RNAs (piRNAs). Aub Ago3 are found germ cell cytoplasm, where they function ping-pong cycle to consume transposon mRNAs. The nuclear protein is required for silencing both somatic follicle cells, yet precise mechanisms by which acts remain largely unclear. We investigated role combining type-specific knockdowns measurements steady-state mRNA levels, nascent synthesis, chromatin state, abundance. In loss led concerted effects transcripts mRNAs, indicating that through transcriptional gene (TGS). showed disproportionate impacts it also exerts an effect post-transcriptional (PTGS). knockdown affected levels piRNAs presumably bound Ago3, perhaps explaining its impacts. Overall, our results indicate plays multiple roles piRNA pathway, part enforcing repression local states transcription but participating biogenesis.