The Drosophila midgut epithelium undergoes continuous regeneration that is sustained by multipotent intestinal stem cells (ISCs) underneath. Notch signaling has dual functions to control ISC behavior: it slows down the ISC proliferation and drives the activated ISCs into different differentiation pathways at a dose-dependent manner. Here we identified a molecular mechanism to unite these two contradictory functions. We found JAK-STAT signaling controls ISC proliferation and this ability is negatively regulated by Notch at least through a transcriptional control of the JAK-STAT signaling ligand, unpaired (upd). This study provides insight into how stem cells, under steady conditions, balance the processes of proliferation and differentiation to maintain the stable cellular composition of a healthy tissue.
Copyright 2010 Wiley-Liss, Inc.