Fig. 5. Fgf8a is a strong inducer of Wnt8 in animal explants and in whole embryos. (A) Animal explants derived from embryos injected with Fgf8a (F) or with a combination of Fgf8a and Chordin (C+F) show a strong upregulation of Wnt8 after 4 hours in culture. For comparison, Wnt8 (W) or Wnt8 and Chordin (C+W) co-injection had little effect on the expression levels of Fgf8. U, uninjected animal explant. Values (n=3) are presented as mean±s.e.m.; ^*P<0.05, versus uninjected animal explant (U). (B) In whole embryos, loss of Fgf function by injection (arrow) of Fgf8aMO (50 ng) or a dominant-negative Fgf receptor (XFD; 2 ng) results in a reduction of Wnt8 expression in the involuting mesoderm at stage 12. Conversely, Fgf8a (5 pg) mis-expression strongly upregulates Wnt8. For all injections, dorsal and lateral views (control and injected sides) of the same embryo are shown. Dorsal views, anterior to the top, injected side to the right (arrows). Lateral views, dorsal to the top; for the control side anterior is to the left, for the injected side anterior is to the right.