Fig. 3. Interfering with XSRF function changes cell fates. (A,B) Phenotypes of embryos injected with DN XSRF RNA dorsally as compared with uninjected embryos. (C,D) Embryos were injected at the four-cell stage in the animal pole region with DN XSRF mRNA (1-2 ng) and the animal cap explants cut at stage 8.5 were cultured to stage 10.25 in the presence or absence of Activin protein (5 ng/ml) and then analyzed by RT-PCR. (C) DN XSRF alone induced mesoderm (Chordin and VegT), endoderm (Sox17ß) and neural (Zic3) markers in animal caps. Epidermal keratin (Exkeratin), an epidermal marker, was reduced by injection of DN XSRF. (D) DN XSRF enhanced the ability of Activin to induce target genes in animal caps. ODC was used as a loading control; Uninjected, uninjected control animal caps.