Novel intrinsic factor Yun maintains female germline stem cell fate through Thickveins

Germline stem cells (GSCs) are critical for the reproduction of an organism. The self-renewal and differentiation of GSCs must be tightly controlled to avoid uncontrolled stem cell proliferation or premature stem cell differentiation. However, how the self-renewal and dif-ferentiation of GSCs are properly controlled is not fully understood. Here, we find that the novel intrinsic factor Yun is required for female GSC maintenance in Drosophila. GSCs undergo precocious differentiation due to de-repression of differentiation factor Bam by defective BMP/Dpp signaling in the absence of yun. Mechanistically, Yun associates with and stabilizes Thickveins (Tkv), the type I receptor of Dpp/ BMP signaling. Finally, ectopic expression of a constitutively active Tkv (TkvQD) completely suppresses GSC loss caused by yun depletion. Collectively, these data demonstrate that Yun functions through Tkv to maintain GSC fate. Our results provide new insight into the reg-ulatory mechanisms of how stem cell maintenance is properly controlled.

Automated summary

This study reveals the important role of the novel intrinsic factor Yun in maintaining female GSCs in Drosophila. The absence of Yun results in premature differentiation of GSCs due to defective BMP/Dpp signaling. Yun functions through its association with and stabilization of Thickveins to maintain GSC fate.