Fig. 1. Ctnnb1 deletion from early-stage mouse UGS epithelium (UGE) impairs cloacal division, prostate field specification and formation of prostatic buds and KRT14⁺ basal epithelium.

(A–B) Electron micrographs of E17.5 Shh^cre/+;Ctnnb1^tm2Kem/+ (control) and Shh^cre/+; Ctnnb1^{tm2Kem/tm2Kem} (Ctnnb1^cLOF) UGE after removal of overlying UGS stroma. Prostatic buds are pseudocolored red. Arrow indicates an inappropriate hindgut-UGE connection (rectourethral fistula, rf) in Ctnnb1^cLOF mice. (C–D) E17.5 male UGSs were stained by ISH to visualize the prostatic bud marker Nkx3-1 (purple) and counterstained by IHC to visualize UGE marked by cadherin 1 (CDH1). (E–H) E17.5 UGS sections were immunofluorescently labeled to detect CTNNB1, CDH1 and the UGS basal epithelial cell marker KRT14. Nuclei were stained with DAPI. Staining patterns in each panel represent three males. Abbreviations are bl: bladder, bn: bladder neck, hg: hindgut, sv: seminal vesicle, wd: Wolffian duct. Arrowheads indicate prostatic buds.