The miRNA pathway intrinsically controls self-renewal of XXXX germline stem cells.

@entity46050 @entity33321 @entity238
Stem cells uniquely self-renew and maintain tissue homoeostasis by differentiating into different cell types to replace aged or damaged cells [1]. During oogenesis of @entity238 , self-renewal of germline stem cells (GSCs) requires both intrinsic signaling mechanisms and extrinsic signals from neighboring niche cells [2]. Emerging evidence suggests that microRNA (miRNA)-mediated translational regulation may also control @entity238 GSC self-renewal [3, 4]. It is unclear, however, whether the miRNA pathway functions within stem cells or niche cells to maintain GSCs. In @entity238 , @entity33321 (Dcr-1) and the double-stranded RNA binding protein @entity46050 ( @entity46050 ) catalyze miRNA biogenesis [3-5]. Here, we generate @entity46050 knockout ( @entity46050 (KO)) flies by ends-out homologous recombination and show that @entity46050 is essential for embryonic viability and ovarian GSC maintenance. Both developmental and miRNA processing defects are rescued by transgenic expression of @entity46050 , but not @entity46050 . Furthermore, mosaic germline analysis indicates that @entity46050 is required intrinsically for GSC maintenance. Consistently, GSCs are restored in @entity46050 mutant ovaries by germline expression, but not somatic expression, of @entity46050 . Together, these results demonstrate that @entity46050 , but not @entity46050 , is necessary and sufficient for @entity238 development and the miRNA pathway. Our study strongly suggests that miRNAs play an intrinsic, but not extrinsic, role in @entity238 female GSC self-renewal.
