Kif26b, a kinesin family gene, regulates adhesion of the embryonic kidney mesenchyme

The kidney develops through reciprocal interactions between two precursor tissues: the metanephric mesenchyme and the ureteric bud. We previously demonstrated that the zinc finger protein Sall1 is essential for ureteric bud attraction toward the mesenchyme. Here, we show that Kif26b, a kinesin family gene, is a downstream target of Sall1 and that disruption of this gene causes kidney agenesis because of impaired ureteric bud attraction. In the Kif26b-null metanephros, compact adhesion between mesenchymal cells adjacent to the ureteric buds and the polarized distribution of integrin alpha 8 were impaired, resulting in failed maintenance of Gdnf, a critical ureteric bud attractant. Overexpression of Kif26b in vitro caused increased cell adhesion through interactions with nonmuscle myosin. Thus, Kif26b is essential for kidney development because it regulates the adhesion of mesenchymal cells in contact with ureteric buds.