c-Fos Repression by Piwi Regulates Drosophila Ovarian Germline Formation and Tissue Morphogenesis

Drosophila melanogaster piwi functions within the germline stem cells (gscs) and the somatic niche to regulate gsc self-renewal and differentiation. how piwi influences gscs is largely unknown. we uncovered a genetic interaction between piwi and c-fos in the somatic niche that influences gscs. c-fos is a proto-oncogene that influences many cell and developmental processes. in wild-type ovarian cells,c-fos is post-transcriptionally repressed by piwi,which destabilized the c-fos mrna by promoting the processing of its 3′ untranslated region (utr) into piwi-interacting rnas (pirnas). the c-fos 3′ utr was sufficient to trigger piwi-dependent destabilization of a gfp reporter. piwi represses c-fos in the somatic niche to regulate gsc maintenance and differentiation and in the somatic follicle cells to affect somatic cell disorganization,tissue dysmorphogenesis,oocyte maturation arrest,and infertility. © 2016 klein et al.