Defect in OFT formation of the <i>Furin</i> mutants.

(A, B) Right side views of E9.5 control and Nkx2-5IRES-Cre/+/Furinfl/fl mutant embryos. (C) Measurement of OFT length as shown in A and B with black bars. (D) Measurement of OFT angle as shown in A and B in red (n = 29 for control embryos and 17 for Furin mutants). *P<0.05 for unpaired Student’s t test. (E-F) Sagittal section showing ectopic expression of cTNI and MF20 in the dorsal pericardial wall (DPW) of mutant and control E9.5 embryos. Red brackets indicate the extend of the differentiated cells. Location of atria and OFT is shown. (K-P) Sagittal section showing PH3-positive cells in the DPW of control and mutant embryos. ISL1 staining identify CPCs. (P) Quantification showing a reduction of mitotic index in mutant embryos compared to control while it is unchanged in the underlying endoderm (n = 3 for each genotype). (Q) Western blot analysis of BMP4 and pSmad1,5,8 expression in protein extract from 3 pooled body walls of E9.5 control and mutant embryos.