Fig. 7.

Elevated cell death of the urorectal mesenchyme of Pdgfra-conditional knockout embryos. Transverse (a) and mid-sagittal (b) sections of E12.5 mutant and control embryos were analyzed using TUNEL analysis. c Percentages of apoptotic cells in the peri-urethra and peri-cloaca mesenchyme of wild-type (filled bar) and Pdgfra-cKO embryos (un-filled bars) were shown. Apoptotic cells (red) were abundantly localized at the mesenchyme surrounding the cloaca and the urethra (a); at the urorectal septum, apical genital mesenchyme and the urethral plate of the mutant embryos. In contrast, apoptotic cells were localized only at the tip of the urethra (future urethra orifice) and at the cloaca membrane. Regions highlighted with dotted line were magnified and shown on the right. ur urethra, cl cloaca, agm apical genital mesenchyme, up urethral plate, ut urethral tip, cm cloaca membrane urs urorectal septum. n = number of embryos analyzed