Fig. 4. Xfz3 and Xwnt1 induce Xslug at similar times in early neurula stage explants, in parallel with onset of Xslug expression in whole embryos. Animal caps expressing chordin, chordin plus Xfz3, or chordin plus Xwnt1, as well as control animal caps and sibling embryos, were harvested at the stages indicated and processed for RT-PCR analysis as in Fig. 3.