Fig. 3.

pax7 pattern in the brain is positively regulated by FGF, Wnt and retinoid signals. (A–D) FGF8 gain of function expands pax7 expression into forebrain, while FGF8 depletion leads to lack of pax7 at induction stage (stage18, A, B) and in later development (stage 22, C, D). (E–F) Wnt7b over-expression and beta-catenin morpholino injections demonstrate the requirement for Wnt signals in pax7 patterning. (G) Similarly, blocking retinoic acid signaling resulted in defective pax7 expression.