The regulation of Drosophila ovarian stem cell niches by signaling crosstalk

The Drosophila female ovary is an excellent model for investigating how multiple stem cell types are coordinately regulated in vivo. The ovary contains at least two stem cell types, germline stem cells (GSCs) and somatic follicular stem cells (FSCs). Although GSCs and FSCs are maintained within a distinct extra-cellular microenvironment, known as a niche, they share some common signaling molecules to generate their own niche. To properly maintain these stem cell types, understanding how signaling molecules are regulated is essential. In this review, we summarize the recent understanding of the mechanisms maintaining GSCs and FSCs from the perspective of growth factor regulation and discuss how these regulatory mechanisms contribute to stem cell maintenance, competition, and survival.