Movie 1 and 2. Pax8, NCAM, and DAPI staining in E18 wild type (Movie 1) and ΔSRM mutant kidney (Movie 2). Immunofluorescence performed on 80μm sections from E18 kidney for Pax8 (green), NCAM (red), and DAPI (blue). Movies 1 and 2 are made from a 20μm Z stack from confocal imaging. In Movie 1 (wild type kidney) ureters are stained with Pax8 and DAPI. Pax8/NCAM is detectable in pretubular aggregates and differentiated structures (RVs and comma/S-shaped bodies). Cap mesenchyme located in the periphery is negative for Pax8, and expresses low levels of NCAM. In the mutant (Movie 2) there is no Pax8 negative cap mesenchyme above the UB, but is instead replaced with Pax8/ NCAM positive aggregated structures indicative of induced cap mesenchyme and developing RVs. We also observed isolated Pax8/NCAM positive cells at the periphery of the kidney above the UB in the mutant, but not the wild type, further indicative of abnormal induction.