The Steroid Hormone Ecdysone Functions with Intrinsic Chromatin Remodeling Factors to Control Female Germline Stem Cells in Drosophila

SummarySteroid hormones are known systemic regulators of multiple normal and cancerous tissues; however, whether or how they impact the fate and function of adult stem cells is unclear. In the Drosophila ovary, insulin signals modulate the proliferation and self-renewal of germline stem cells (GSCs), yet despite evidence that additional systemic factors control GSC activity, these have remained largely unknown. Here, we report that ecdysone, a steroid hormone structurally related to mammalian sex steroids, directly regulates adult GSC proliferation and self-renewal independently of insulin signaling. Ecdysone controls GSCs through a functional interaction with the chromatin remodeling factors ISWI, an intrinsic epigenetic factor required for GSC fate and activity, and Nurf301, the largest subunit of the ISWI-containing NURF chromatin remodeling complex. Our findings support a link between systemic steroid hormones and the intrinsic chromatin remodeling machinery as a potential mechanism to promote broad transcriptional programs required for adult stem cell self-renewal.

► Steroid hormone ecdysone directly controls Drosophila germline stem cells (GSCs)
► Ecdysone controls GSCs via a specific pathway branch and independently of insulin
► GSC division and self-renewal requires Nurf301, a chromatin remodeling factor
► Ecdysone functionally interacts with ISWI, Nurf301, and Dpp to control GSC number.