H3K27me3 ChIP-seq experiment in fruitfly testis somatic gonadal cells

In many metazoans, germ cells are separated from somatic lineages early in development and maintain their identity throughout life. Here we show that a Polycomb group (PcG) component, Enhancer of Zeste [E(z)] H3K27me3-specific methyltransferase, maintains germline identity in Drosophila adult testes. We find excessive early-stage somatic gonadal cells in E(z) mutant testes, which originate from both over-proliferative cyst stem cells and germ cells turning on an early-stage somatic cell marker. Using complementary lineage-tracing experiments in E(z) mutant testes, a portion of excessive early-stage somatic gonadal cells are found to derive from early-stage germ cells, including germline stem cells. Interestingly, knocking down E(z) specifically in somatic cells caused this germline-to-soma change, suggesting a non-cell autonomous role of E(z) to antagonize somatic identity in germ cells. Using fly testis specifically expressing E(z) shmiR RNAi in germ cells by nos promoter driven GAL4>UAS system, ChIPseq with H3K27me3 antibody was performed, where H3K27me3 is only detected in somatic cells.