Fig. 7. Dsh function is required for endomesoderm specification and for the accumulation of ß-catenin in the nuclei of vegetal blastomeres. (A) Injection of mRNA (1.9 mg/ml) encoding the DIX domain of LvDsh resulted in suppression of endoderm and mesoderm formation and a phenotype indistinguishable from that produced by overexpression of cadherins or GSK3ß (Emily-Fenouil et al., 1998; Wikramanayake et al., 1998; Logan et al., 1999). (B,C) Overexpression of the PDZ domain of LvDsh (2.0 mg/ml mRNA) or the DIX domain of LvAxin (3.6 mg/ml mRNA) did not produce apparent phenotypes. Embryos shown in (A-C) are at 20 hours, 20 hours and 18 hours of development, respectively. (D,E) Overexpression of the DIX domain of LvDsh blocked the nuclear accumulation of ß-catenin in vegetal blastomeres (arrow, E), as shown by immunostaining using an anti-Lv-ß-catenin antibody.