During kidney development, Ret receptor tyrosine kinase signalling promotes the cell movements that give rise to the ureteric bud (UB), which branches to form the renal collecting system, from the Wolffian duct. The ETS transcription factors Etv4 and Etv5 act downstream of Ret in this process, but how? Frank Costantini and colleagues now report that during mouse kidney development, Etv4 and Etv5 mediate the formation of the UB tip domain where branching occurs and which induces surrounding mesenchyme to form nephrons (see p. 1975). To examine Etv4 and Etv5 function during kidney development, the researchers analysed the contribution of compound mutant cells to chimeric kidneys. They report that, like Ret−/− cells, Etv4−/−;Etv5+/− cells contribute to some trunks of the initial UB branches but to few tips; Etv4−/−;Etv5−/− cells make an even smaller contribution to the UB. Together, these results suggest that Etv4 and Etv5 play a cell-autonomous role in the Ret-promoted, Wolffian duct cell rearrangements, and importantly, that they also act downstream of other signals that drive kidney morphogenesis.
- © 2010.