The Fruitfly Testis Niche (IMAGE) University of Pennsylvania School of Medicine Caption The hub cells provide self-renewal signals and anchor the two stem cell populations of the testis niche, the somatic cyst stem cells (CySCs) and the germline stem cells (GSCs). GSC divisions to produce gonialblast (Gb) daughters exhibit delayed completion of cytokinesis, resulting in GSC-Gb pairs remaining attached for a significant amount of time. Our results indicate that this delay may serve to coordinate the production of CySC and GSC daughter cells to ensure the correct association of one Gb with two somatic cyst cells. The formation of this functional unit of differentiation is absolutely required for the production of sperm. Credit Stephen DiNardo, PhD, and Kari F. Lenhart, PhD, Perelman School of Medicine at the University of Pennsylvania; Developmental Cell Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.