Figure 1.

Smad4 inactivation in the mesenchyme of the lower urinary tract. (A) Tbx18-Cre transgene drives Cre-mediated loxP recombination of a floxed allele of Smad4, resulting in the Smad4 knockout allele lacking exon 8. (B–G) Immunostaining with an anti-Smad4 antibody that detects the full-length Smad4 protein shows the lack of full-length Smad4 protein in the mesenchyme of mutants (E–G) compared with control sections (B–D). Higher magnification of Smad4 immunostaining of control and mutant is shown in (D) and (G), respectively. Epi, epithelium; Mes, mesenchyme; MH1, MAD (mothers against decapentaplegic)-homology 1 domain; MH2, MAD-homology 2 domain; SAD, Smad activation domain.