Fig. 1. Cre-mediated deletion of Foxh1 in LPM. (A-C) Mice harboring the Lefty2-3.0 Cre transgene were crossed with transgenic mice that harbor the reporter construct CAG-CAT-Z (Sakai and Miyazaki, 1997), which expresses lacZ in the presence of the Cre recombinase. Embryos containing both Lefty2-3.0 Cre and CAG-CAT-Z were stained with X-gal at E7.5 (A) and E8.2 (B). A transverse section at the plane indicated in B is shown in C. At E7.5, most of the mesoderm exhibited X-gal staining whereas the ectoderm and endoderm did not. At E8.2, the anterior region of LPM, paraxial mesoderm and the heart were positive for staining, whereas the posterior portion of LPM and midline structures (arrowhead in B), including the PFP, were negative. a, anterior; p, posterior; l, left; r, right. (D-G) Whole-mount in situ hybridization analysis of Foxh1 transcripts. Lateral views are shown for wild-type (WT) (D) and Foxh1^c/- (F) embryos at E7.5 and anterior views for wild-type (E) and Foxh1^c/- (G) embryos at E8.2. In the Foxh1^c/- embryos, Foxh1 mRNA was not detected in the regions that were positive for X-gal staining in A-C.