miR-932 Suppresses the Expression of Germline-Specific vasa in Somatic Drosophila Testis Hub Cells.

Germline cells are specified early in embryogenesis and are encapsulated by somatic cells to form the gonads (testis or ovary). This development requires genes with expression restricted to germline cells, such as the DEAD-box RNA helicase Vasa, an evolutionarily conserved protein exclusively expressed in the germline of the testis. However, the mechanisms underlying germline-specific expression remain poorly understood. To identify microRNAs that function in the somatic cells of the testis, we employed the binary Gal4/UAS expression system, which enables the expression of UAS-microRNA sponges in somatic cells driven by somatic Gal4 drivers. The screening identified the miR-932 sponge as a regulator. Testes with hub-specific Gal4 driven expression of the UAS-miR-932 sponge exhibit ectopic Vasa expression in the hub cells. Thus, our findings suggest that miR-932 in the somatic hub cells prevents Vasa expression in these cells.