Mesodermal and anterior marker gene expression in Tenm4m1/m1mutant embryos. Whole-mount in situ hybridization was performed to examine the expression of marker genes (Brachyury, Foxa2, Lhx1, Otx2 and Bmp4). Wildtype embryos are oriented with the anterior side of embryos on the left. A-P axis orientation may vary because the A-P axis was not specified in mutants. Brachyury is expressed in the primitive streak and notochord of an E7.5 wildtype embryo (A). Tenm4m1/m1mutants at E7.5 lack Brachyury expression in the posterior embryonic region (F), although a weak signal is detected in extraembryonic tissue. Foxa2 is expressed in the primitive streak in an E7.0 wildtype embryo (B), but not in Tenm4m1/m1(G). Lhx1 is expressed in mesoderm wings and anterior visceral endoderm at E7.0 (C), but not in Tenm4m1/m1(H). Otx2 is restricted to the anterior epiblast of an E7.5 wildtype embryo (D), but not restricted in Tenm4m1/m1(I). Bmp4 is expressed in extraembryonic ectoderm and extraembryonic mesoderm at E7.5 (E). Tenm4m1/m1mutant shows ectodermal expression but not mesodermal (J). Anterior streak (as), anterior visceral endoderm (ave), extraembryonic ectoderm (ee), primitive streak (ps). Bar 100 μm.