Figure 3. Pax2 signaling remains intact in the absence of Lrp4.

Pax2 is expressed normally in the metanephric mesenchyme and the ureteric bud, indicated by the red arrows, at E10.5 in the wild type and Lrp4 knockout mice (a and b). At E11.5, Pax2 is expressed normally in both the ureteric bud and metanephric mesenchyme, the latter indicated by black arrows, of wild type (c) and Lrp4 knockout animals (d). However, the ureteric bud fails to invade the metanephric mesenchyme and does not undergo secondary branching in the Lrp4 knockout indicated by the yellow arrow (d). The black arrows indicate mesenchymal expression of Pax2, which is present in the wild-type, but subsequently lost in the knock-out kidney mesenchyme at E12.5 (e and f).