Figure 1: Nf2 deletion leads to kidney defects due to defective branching morphogenesis.

(a) NF2 protein is apically localized in all kidney epithelia: UB (pink arrows), collecting duct (yellow arrowhead) and early nephron (blue arrowhead). See Supplementary Fig. 1d for counterstaining with E-CADHERIN to mark the UB and early nephron. (b–d) Macroscopic view of the urogenital system from wild-type and Nf2^UB−/− mutants at P0 shows severe kidney hypoplasia (arrows) in Nf2 mutants. (e) Quantification revealed a 76% decrease in kidney size in Nf2 mutants (n=14 kidneys) compared with controls (n=9). Error bars represent s.d., ***P<0.0001, Student’s t-test. (f–h) Periodic acid-Schiff (PAS) staining of P0 kidneys from wild type and Nf2^UB−/−. (i,j) Ex vivo analysis demonstrates loss of ureter branching in Nf2^UB−/− compared with controls, visualized using anti-CALBINDIN antibody (pink arrows point to UB tips, yellow arrowheads to the ureter/collecting duct (CD) and asterisks mark the Wolffian duct). (k) Quantification of ureter branching capacity from ex vivo kidney explant experiments. For quantification, 21 kidneys explants were used in both genotypes. Error bars represent s.d., ***P<0.0001, Student’s t-test. The y axis represents the number of ureteric tips after 48 h of culture. (l–q) Similar branching defects were observed in vivo using immunostaining on sections (PAX2 antibody, E11.5) and whole-mount immunostaining (CALBINDIN antibody, E11.75 and E12.5). Scale bars represent 100 μm (a), 1 mm (b–d), 0.5 mm (f–h), 250 μm (i,j) and 200 μm (l–q).