Foxf1 is a crucial factor for ureter development.

(A-H) Histological and molecular analysis of E14.5 control and Tbx18cre/+;HprtFoxf1DN/y (Foxf1DN) ureters after 6 d of culture. (A,B) Hematoxylin and Eosin (HE) stainings and (C-H) analysis of cytodifferentiation by immunofluorescence for ACTA2/CDH1 (C,D), TAGLN (E,F) and ΔNP63/UPK1B (G,H) on proximal ureter sections. (I-Q) Histological, cellular and molecular analysis of control and Tbx18cre/+;HprtFoxf1DN/y (Foxf1DN) ureters at E12.5 and E14.5. (I) Hematoxylin and Eosin staining on transverse sections of the proximal ureter at E12.5 and E14.5. (J-N) RNA in situ hybridization analysis for Ptch1 (J), Bmp4 (K), Myocd (L), Myh11 (M) and Tagln (N) expression on transverse sections of the proximal ureter at E12.5 and E14.5. (O-Q) Analysis of cell death by the TUNEL assay (O), and of cellular proliferation by the BrdU incorporation assay (P) on transverse sections of the proximal ureter at E12.5 and E14.5. Black circles in H mark the epithelium (UE) and the inner (IM) and outer (OM) mesenchymal compartments of the ureter for which proliferation was quantified. (Q) Quantification of BrdU-positive cells. E12.5 (n = 3), wildtype versus mutant: IM, 0.329±0.007 vs 0.276±0.011, P = 0.002; OM, 0.216±0.015 vs 0.234±0.019, P = 0.310; UE, 0.412±0.016 vs 0.311±0.026, P = 0.004. E14.5 (n = 3), wildtype versus mutant: IM, 0.199±0.013 vs 0.216±0.003, P = 0.153; OM, 0.209±0.005 vs 0.197±0.013, P = 0.288; UE, 0.225±0.014 vs 0.256±0.020, P = 0.144. Values are displayed as mean ± sd. **, P≤0.01; two-tailed Student’s t-test.