Function of zebrafish beta-catenin and TCF-3 in dorsoventral patterning.

We report the molecular cloning and expression of the zebrafish tcf-3 homologue and study its function and that of zebrafish betacat in dorsoventral patterning. Overexpression of mutant zTcf-3 products and Cadherin leads to a reduction in the expression of the dorsal-specific genes goosecoid and chording at the blastula stages, indicating a conserved role for betacat and tcf-3 in zebrafish dorsal axis induction. Later during gastrulation, overexpression of these same products leads to the ectopic expression of dorsal-specific genes in the marginal zone and the induction of ectopic axes, suggesting an additional role for betacat and Tcf-3 at these later stages in the repression of dorsal fates. Copyright 1998 Elsevier Science Ireland Ltd. All Rights Reserved.