Fig. 7. Effect of XcadVP16 expression and FGF treatment in the hindbrain. Dorsal views of stage 15 embryos hybridized with Hoxb4 (A) or Hoxb9 (B), after electroporation with the XcadVP16 expressing construct unilaterally on the left side of the hindbrain. The embryos were cultured overnight (A) in the absence of or (B) in the presence of an exogenous FGF. In both cases (A,B), upregulation and anterior expansion of each Hox gene is observed in the anterior hindbrain region (area between arrowheads) in response to FGF treatment (see also Fig. 5A for comparison). The asterisk (^*) in A shows that the anterior limit of expression on the non-electroporated side is at the level of otic vesicle. The asterisk in B is just posterior to the OV.