Drosophilasertaddomain Proteintaranisis Required In Somatic Cells For Maintenance Of Male Germline Stem Cells

Background Polycomb proteins are essential for maintaining stem cell identity across different stem cell niches. However, how they function to maintain stem cell niches is not fully understood. Results Here we show that the SERTAD protein Taranis (Tara), which is a Polycomb-trithorax group protein, is expressed in the adult testis niche and plays a role in its maintenance inDrosophila. We found thattarais expressed in early cyst cells, likely including somatic cyst stem cells (CySCs) ofDrosophilamale testis tip region, which houses both germline and somatic cyst stem cells along with the hub cells, forming the stem cell niche. Consistent with its expression, we found that, while loss oftarain germline cells only had minimal effects,taraknockdown in all cells or only in somatic cells of the niche reduced the number of not only somatic cells, but also germline stem cells (GSCs). We further found that Tara might antagonize Notch signaling in CySCs to maintain the stem cell niche. Conclusions Our studies suggest that Tara might function in somatic CySCs for GSC maintenance in theDrosophilatestis.