A single-cell atlas and lineage analysis of the adult Drosophila ovary

The Drosophila ovary is a widely used model for germ cell and somatic tissue biology. Here we use single-cell RNA-sequencing (scRNA-seq) to build a comprehensive cell atlas of the adult Drosophila ovary that contains transcriptional profiles for every major cell type in the ovary, including the germline stem cells and their niche cells, follicle stem cells, and previously undescribed subpopulations of escort cells. In addition, we identify Gal4 lines with specific expression patterns and perform lineage tracing of subpopulations of escort cells and follicle cells. We discover that a distinct subpopulation of escort cells is able to convert to follicle stem cells in response to starvation or upon genetic manipulation, including knockdown of escargot , or overactivation of mTor or Toll signalling. Cell types in the adult Drosophila ovary vary during homeostasis and differing environmental conditions. Here, the authors use single-cell RNA-sequencing to identify 26 ovarian cell populations and show cellular plasticity in which escort cells can convert to follicle stem cells upon starvation.