Fig. 4

Schematic depicting cells of intestinal lineages in humans and Drosophila. The pathways of stem cell maintenance and differentiation are largely conserved between Drosophila and mammals with minor differences. Gut plasticity and homeostasis are maintained by regeneration of the gut epithelium. Intestinal stem cells (ISCs) divide asymmetrically to form transient amplifying (TA) cells in humans and enteroblasts (EB) in Drosophila, which differentiates to ECs and EEs. The ECs and EEs cells in the mammalian gut can further be divided into goblet cell (secrets mucous), paneth cell (secrets lysozymes), and tuft cell (expresses chemosensory receptors). In the Drosophila intestine, cardia cells produce mucus layer (analogous to mammalian goblet cell), aEC2/3 cells release lysozyme (analogous to mammalian paneth cell), and gustatory receptor-expressing cells in proventriculus (PV) are analogous to mammalian tuft cells. Intestinal cell types and their markers in mammalian and Drosophila intestines are shown (only one marker for each cell type has been shown). Trmp5 (Transient Receptor Potential Cation Channel Subfamily M Member 5), Lyz (Lysozyme), Enteroendocrine (EE), Bmi1 (B lymphoma Mo-MLV insertion region 1 homolog), Muc2 (Mucin 2), Enterocyte (EC), Fabp1 (Fatty Acid Binding Protein 1), TA (Transiently Amplifying), Atoh1 (Atonal BHLH Transcription Factor 1), ISC (Intestinal Stem Cell), Lgr5 (Leu-rich repeat-containing G protein-coupled receptor 5), GR (Gustatory Receptor), LysX (Lysozyme X), Pros (Prospero), Pgant4 (Polypeptide N-Acetylgalactosaminyltransferase 4), Pdm1 (POU domain protein 1), and Klu (Klumpfuss). Schematics are to show diversity in intestinal cell types and to highlight similarities between mammalian and Drosophila model systems; neither shape, size, nor color has depicted the real cells