Figure 2.

Duplications of the neural tube in Tcf4^−/−/Tcf1^−/− embryos. Whole-mount in situ hybridizations of E10.5 littermates using a Wnt1 probe as a marker for neural tube. (A) Tcf4^+/−/Tcf1^−/− embryo; (B) right side, (C) left side and (D) close-up views of a representative Tcf4^−/−/Tcf1^−/− embryo. Lateral and close-up views reveal that the neural tube appears to split at the caudal end of mutant embryos. In some regions (see the arrow in (D) and the corresponding section in (E)), complete duplications of the neural tube are observed. Note that Wnt1 expression appears normal in the anterior half of Tcf4^−/−/Tcf1^−/− embryos.