Transcription factor patterns cells in the mouse kidney collecting ducts.

Although most nephron segments contain one type of epithelial cell, the collecting ducts consists of at least two: intercalated (IC) and principal (PC) cells, which regulate acid-base and salt-water homeostasis, respectively. In adult kidneys, these cells are organized in rosettes suggesting functional interactions. Genetic studies in mouse revealed that transcription factor coordinates IC and PC development. induces the expression of IC specific genes, including specific H-ATPase subunits and in turn, initiates Notch signaling in PCs but inhibits Notch signaling in ICs. inactivation deletes ICs, whereas inactivation results in the forfeiture of discrete IC and PC identities. Thus, is a critical regulator of IC-PC patterning, acting cell-autonomously in ICs, and non-cell-autonomously in PCs. As a result, regulates the diversification of cell types which is the central characteristic of 'salt and pepper' epithelia and distinguishes the collecting duct from all other nephron segments.