A genome-scale in vivo RNAi analysis of epithelial development in Drosophila identifies new proliferation domains outside of the stem cell niche

Abstract

The Drosophila oogenesis system provides an excellent model to study the development of epithelial tissues. Here, we report the first genome-scale in vivo RNA interference (RNAi) screen for genes controlling epithelial development. By directly analysing cell and tissue architecture we identified 1125 genes, which we assigned to seven different functions in epithelial formation and homeostasis. We validated the significance of our screen by generating mutants for Vps60, a component of the endosomal sorting complexes required for transport (ESCRT) machinery. This analysis provided new insights into spatiotemporal control of cell proliferation in the follicular epithelium. Previous studies have identified signals controlling divisions in the follicle stem cell niche. However, 99% of cell divisions occur outside of the niche and it is unclear how these divisions are controlled. Our data distinguish two new domains outside of the stem cell niche where there are differing controls on proliferation. One domain abuts the niche and is characterised by ESCRT, Notch and JAK/STAT-mediated control of proliferation. Adjacent to this domain, another domain is defined by loss of the impact of ESCRT on cell division. Thus, during development epithelial cells pass through a variety of microenvironments that exert different modes of proliferation control. The switch between these modes might reflect a decrease in the 'stemness' of epithelial cells over time.

The genetics of egg retention and fertilization success inDrosophila: One step closer to understanding the transition from facultative to obligate viviparity

“…Corp is ovarylimited and it is thought to be a negative regulator of apoptotic signaling, while msn plays a role in oogenesis and regulation of embryonic cell shape (Flybase ; Table S2). Two non-synonymous mutations occurred in feo, a gene with the inferred biological function of germarium-derived egg chamber formation (Berns et al 2014). Several candidate genes appear to function in male-specific tissues, implicating a possible role for these genes in fertilization success.…”

Genome-wide RNAi Screen Identifies Networks Involved in Intestinal Stem Cell Regulation in Drosophila

“…Recent developments in genome-wide RNA interference (RNAi) techniques in Drosophila have enabled the knockdown of near-complete sets of genes involved in cellular processes in living animals (Dietzl et al, 2007; Ni et al, 2011). In addition, genome-wide RNAi screens have been performed to identify regulatory networks function in several somatic tissues, including stem cells (Baumbach et al 2014; Berns et al 2014; Neely et al 2010; Neumüller et al, 2011; Schnorrer et al 2010; Yan et al, 2014). In this study, we carried out a genome-wide RNAi screen for genes that regulate ISC fates.…”

A pooled shRNA screen for regulators of primary mammary stem and progenitor cells identifies roles for Asap1 and Prox1

“…Rather, such screening strategies have been restricted to mammary epithelial and breast cancer cell lines, which offer the advantages of being readily available and amenable to genetic manipulation [ 12 - 15 ]. In other organs, primary cells have been used in RNAi screens to study tissue stem and progenitor cell behavior in more complex and physiological contexts [ 16 - 19 ]. To explore novel molecular regulators of MaSCs and MaPCs, we have utilized a targeted shRNA library to interrogate freshly isolated MaSC-enriched cells ex vivo .…”