Identification of progenitor cells and their progenies in adult Drosophila midgut

The intestinal epithelium in the anterior and posterior of the Drosophila midgut, which is maintained by intestinal stem cells (ISCs), represents a genetic tractable system for the study of stem cell biology, epithelial homeostasis and intestinal physiology and function. The ISCs self-renew and periodically generate absorptive enterocyte (EC) and secretory enteroendocrine cell (EE) via a committed progenitor stage termed as enteroblast (EB) or enteroendocrine progenitor (EEP), respectively. The progenitors in adult midgut are commonly referred to as all of the undifferentiated cells, including ISCs, EBs and EEPs. Under normal conditions, each of the above-mentioned specific type of cells can be reliably identified by a single cell marker or a combination of several cell markers. However, in aged or stressed gut, the increased proliferation and differentiation of ISCs may render many cell markers to be no longer strictly-specific to certain cell types. The self-renewal and differentiation abilities of ISCs or a particular cell of interest can be determined by cell lineage tracing analyses. Here, we provide detailed methods for the identification of ISC, EB and EEP in adult Drosophila gut, as well as methods for tracing the progenies of ISCs.