Wnt-6 is expressed in the ureter bud and induces kidney tubule development in vitro

The embryonic kidney is a classic developmental model system for studying inductive tissue interactions that govern organogenesis. We report here that Wnt‐6 is expressed in the ureter bud, and that cell lines expressing Wnt‐6 induce nephrogenesis in vitro. Wnt‐6 cells induce tubules with similar kinetics to spinal cord (SPC) and lead to induced expression of Pax2, Pax8, Sfrp2, and E‐cadherin genes, early markers of tubulogenesis. Moreover, Wnt‐6 signaling rescues tubulogenesis in mesenchyme separated from Wnt‐4 mutant embryos and leads to activation of Wnt‐4 transcription. Wnt‐6 also induces a secondary axis in early Xenopus embryos. We conclude that Wnt‐6 is a candidate for the ureter epithelium‐derived signal that leads to activation of kidney tubulogenesis via Wnt‐4. genesis 32:259–268, 2002. © 2002 Wiley‐Liss, Inc.