RT Journal Article SR Electronic T1 Multifunctional RNA-binding proteins mediate ecdysone-dependent germline stem cell self-renewal in Drosophila JF bioRxiv FD Cold Spring Harbor Laboratory SP 321109 DO 10.1101/321109 A1 Danielle S. Finger A1 Vivian V. Holt A1 Elizabeth T. Ables YR 2018 UL http://biorxiv.org/content/early/2018/05/13/321109.abstract AB Steroid hormones promote stem cell self-renewal in many tissues; however, the molecular mechanisms by which hormone signaling is integrated with niche-derived signals are largely uncharacterized. In the Drosophila ovary, the steroid hormone ecdysone promotes germline stem cell (GSC) self-renewal. Despite strong evidence that ecdysone modulates the reception of bone morphogenetic protein (BMP) signals in GSCs, transcriptional targets of ecdysone signaling that facilitate BMP reception are unknown. Here, we report that ecdysone signaling promotes the expression of distinct, multifunctional RNA-binding proteins in GSCs to support their self-renewal. We demonstrate that a group of heterogeneous nuclear ribonucleoproteins (hnRNPs), which regulate splicing, maturation, and localization of nascent mRNAs, are highly expressed in GSCs. In the absence of ecdysone signaling, expression of at least four hnRNPs (squid, hephaestus, Hrb27C, and Hrb87F) is decreased. HnRNPs are intrinsically required for proper GSC self-renewal, and functionally interact with both ecdysone signaling and BMP signaling to maintain GSC number. Our findings support the model that stem cells coordinate local and long-range signals at the transcriptional and post-transcriptional levels to maintain self-renewal in response to physiological demand.SUMMARY STATEMENT Ecdysone signaling promotes expression of heterogeneous ribonucleoproteins to modulate BMP-dependent germline stem cell self-renewal in the Drosophila ovary.