Analysis of the epistatic relationship of HH signaling, FOXF1 and BMP4 in cytodifferentiation of the ureter.

(A-U) Ureters were explanted from E12.5 wildtype, Axin2^creERT2/+;Hprt^Foxf1/y, Tbx18^cre/+;Hprt^Foxf1DN/y or Tbx18^cre/+;R26^mTmG/+ embryos and cultured for 6 d in the presence or absence of 10 μM cyclopamine, 100 ng/μl BMP4, 10 μg/ml NOGGIN, 2 μM Purmorphamine or solvent as indicated. Whole explants were documented by epifluorescence analysis (Q), or were sectioned and proximal regions analyzed by Haematoxylin and Eosin staining (A,E,I,M,R), by immunofluorescence (B-D,F-H,J-L,N-P,S-U) for the SMC marker ACTA2 together with the epithelial marker CDH1 (B,F,J,N,S), for the SMC marker TAGLN without (C,G,K,O) or with the lineage marker GFP (T), and for the urothelial markers ΔNP63/UPK1B (D,H,L,P,U).