Polycomb group gene E(z) is required for spermatogonial dedifferentiation in Drosophila adult testis. Drosophila melanogaster

Dedifferentiation is an important process to replenish lost stem cells during aging or regeneration after injury to maintain tissue homeostasis. Here we report that Enhancer of Zeste [E(z)], a component of the Polycomb Repression Complex 2 (PRC2), is required for the partially differentiated germ cell to dedifferentiate, in order to maintain a stable pool of germline stem cells (GSCs) within the niche microenvironment. During aging, germ cells with reduced E(z) activity have defects in maintaining GSCs, which is not due to increased GSC death or premature differentiation. We found evidence that the decrease of GSCs upon inactivation of E(z) in the germline is likely attributed by defective dedifferentiation. In addition, E(z) mutant germ cells fail to replenish lost GSCs during recovery from genetically manipulated GSC depletion. Together, our data suggest that E(z) acts intrinsically in germ cells for the dedifferentiation process to replenish lost GSCs during both aging and tissue regeneration. Overall design: Examination of H3K4me3 and RNA polymerase II between E(z) bam double mutant testes and bam mutant testes (submitted in GSE19325 (GSM480446, GSM480449)).