Fig. 5.

(A) Representation of the embryonic and extraembryonic genetic constitution of Gpr126^fl/fl;Sox2^Cre embryos when the Sox2^Cre transgene is inherited paternally. Zygotic Sox2^Cre expression deletes Gpr126 in the embryo proper and in the embryonic component of the placenta (white). Gpr126 is not inactivated in the maternal component of the placenta (pink). (B) Images of Gpr126^KO/fl and Gpr126^KO/fl;Sox2^Cre mouse pups at P1. Arrowheads point to joint contractures in the forelimbs and hindlimbs of the mutants. (C to F″) H&E staining of transverse heart sections from Gpr126^KO/fl and Gpr126^KO/fl;Sox2^Cre mutant embryos at E16.5 (C to D″) and P1 (E to F″). Bottom panels: High-magnification views of the right ventricle (′) and left ventricle (″) corresponding to the boxed areas in the main panels. Scale bars, 100 μm. (G) Representation of the embryonic and extraembryonic genetic constitution of Gpr126^fl/fl;Sox2^Cre embryos when the Sox2^Cre transgene is inherited maternally. Note Gpr126 inactivation in both the embryo proper and in the placenta. (H) Breeding strategy used to obtain GPR126^GOF/+;Gpr126^Δ7/Δ7;Sox2^Cre/+ embryos. The parental origin of the Cre transgene determines whether forced GPR126^GOF expression (green) will take place only in the epiblast (paternal inheritance) or will be widespread in embryonic and extraembryonic tissues (maternal inheritance).