GSE40150
Piwi negatively regulates Polycomb Group proteins in maintaining germline stem cells  and oogenesis
Piwi regulates niche and intrinsic mechanisms to maintain germline stem cells in Drosophila, yet how this regulation occurs remains elusive. Here, we show that Piwi interacts with the Polycomb Group Complexes PRC1 and PRC2 to maintain ovarian germline stem cells and oogenesis, as well as to repress retrotransposons. Piwi binds to PRC2 subunits Su(z)12 and Esc in vitro and forms a complex with PRC2 in vivo. Whole-genome analyses of PRC2-mediated histone 3 lysine 27 trimethylation (H3K27m3) in wild type and piwi mutant ovarian nuclei indicate that Piwi inhibits H3K27m3 at PRC2 target genes that are mostly regulators of development and transcription. Overall design: Genome-wide H3K27m3 sites in piwi mutant were explored and compared to those in wild type, via Chromatin immunoprecipitation followed by DNA sequencing technology.