Figure 4. Disruption of Nodal signaling pathway in T^Wis/T^Wis embryos at E8.0.

A–L: Left lateral and ventral views of wild type and T^Wis/T^Wis mutant embryos showing the expression of Nodal in the perinodal region and left LPM in wild type embryos (A, B) but no expression in T^Wis/T^Wis mutants (C, D); Gdf1 bilateral expression in the perinodal region and LPM of wild type embryos (E, F) but only bilateral LPM expression in T^Wis/T^Wis mutants; and Cer2 bilateral perinodal expression in wild type embryos (I, J) but no expression in T^Wis/T^Wis mutants (K, L). Arrowheads indicate LPM expression and arrows indicate perinodal expression. Compass in A refers to A, E, C, G, I, and K; compass in B refers to B, F, D, H, J, and L. M–P: Frontal and left lateral views of Pitx2 expression in the head folds and left inflow tract in wild type embryos (M, N) but only in the head folds of T^Wis/T^Wis mutant embryos (O, P). Pitx2 expression on the right side of T^Wis/T^Wis mutant is in the yolk sac remnants still attached to the embryo. AL, allantois; H, heart; HF, head folds; LIT, left inflow tract.