Fig. 2. Aberrant expression of Nodal, Lefty1, Lefty2 and Pitx2 in Foxh1^c/- embryos. The expression of Nodal (A-E), Lefty1 plus Lefty2 (F,G) and Pitx2 (H-V) in wild-type (WT) and Foxh1^c/- embryos was examined by whole-mount in situ hybridization. Embryos shown in A-H,J,L are at E8.2, whereas the others are at E9.5. Transverse sections at the planes indicated in I, K and M are shown in N-P, Q-S and T-V, respectively. All E8.2 embryos are anterior views, with the exception that left lateral views are shown for B and E. The insets in A, C, D and G show the node in posterior view of the embryos. The white line in the inset of G indicates the location of the node. Most Foxh1^c/- embryos fail to exhibit left-sided gene expression, although some retain Nodal expression in a small region of left LPM adjacent to the node (arrowhead in E) and a low level of left-sided Pitx2 expression in various organs (arrowheads in T-V). a, anterior; p, posterior; l, left; r, right.