Fig. 1.

Tbx18cre drives efficient fibroblast growth factor receptor (Fgfr)2 deletion in the embryonic day (E)13.5 bladder mesenchyme (BM). A: hematoxylin and eosin (H&E) stain of a Tbx18cre:CAG red fluorescent protein (RFP) E13.5 bladder cross-section. B: fluorescent image from an adjacent section to that shown in A illustrating RFP-positive cre expression in the bladder mesenchyme but not in the urothelium (U). C and D: in situ hybridization for Fgfr2 showing expression in both bladder mesenchyme (arrowhead) and urothelial tissue layers (arrow) in a control bladder but an absence of Fgfr2 expression in the bladder mesenchyme in a Fgfr2^BM−/− bladder. In A–D, the dotted line indicates the outer boundary of the developing bladder. UA, umbilical artery. *Bladder lumen. Scale bars = 150 μm. E: quantitative PCR confirmed the significant reduction in Fgfr2 mRNA expression in Fgfr2^BM−/− whole bladders. F: Western blots demonstrating reduced Erk1/2 phosphorylation [phosphorylated (p)Erk1/2] with comparable total (t)Erk1/2 in E16.5 Fgfr2^BM−/− bladders compared with age-matched control bladders. a/b Tubulin (Tub), α/β-tubulin (loading control). Values are mean ± SD. *P < 0.05.