A Modest Proposal: Differentiating Daughters are Sacrificed during Starvation to Protect Stem Cells in the Drosophila Testis.

How tissues adapt to varying nutrient conditions is of fundamental importance for robust tissue homeostasis throughout an organism’s lifespan, but the underlying mechanisms are poorly understood. Here we show that Drosophila testis responds to protein starvation by eliminating transit-amplifying spermatogonia (SGs) while maintaining a reduced pool of actively proliferating germline stem cells (GSCs). During protein starvation, SGs die in a manner that is mediated by the apoptosis of somatic cyst cells (CCs) that encapsulate SGs and regulate their development. Strikingly, GSCs cannot be maintained during protein starvation when CC-mediated SG death is inhibited, leading to an irreversible collapse of tissue homeostasis. SG death is associated with phagocytic processes that may directly promote GSC function via local nutrient recycling. We propose that the regulated elimination of transit-amplifying cells is essential to preserve stem cell function and tissue homeostasis during protein starvation.PhDCellular and Molecular BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120666/1/heiko_1.pd