Fig. 7. OFT defects in Fgfr1 and Fgfr2 double conditional-null embryos. (A) Whole-mount in situ hybridization demonstrating Fgfr1 (a) and Fgfr2 (d) expression in E9.5 mouse embryos. Cryosections reveal detailed expression patterns of Fgfr1 (b,c) and Fgfr2 (e,f). b1 and e1 are higher magnification views of b and e, respectively. (B) H&E staining of E14.5 embryo sections demonstrates that both Fgfr2 conditional mutant and Fgfr1/Fgfr2 (Fgfr1/r2) double conditional mutants have ventricular septal defects (VSDs) (g,h) and DROV (c,d,h), that Fgfr1/Fgfr2 have PTA (l), and Fgfr1 mutants have normal OFTs (b,f,j). Black arrowheads denote OA-associated VSDs, white arrowheads denote DROV, and the red arrow denotes PTA.