mef2ca activates dlx5a, dlx6a, and dlx4b but represses dlx3b. Lateral views of expression of dlx2a (A,B), dlx5a (C,D), dlx6a (E,F), dlx3b (G,H) and dlx4b (I,J) in wild-type (A,C,E,G,I) and mef2ca mutant (B,D,F,H,J) heads of 30 hpf zebrafish embryos. (A,B) mef2ca mutants have no detectable alteration in dlx2a expression, which is expressed throughout pharyngeal arch CNC. (C-F) Expression of both dlx5a and dlx6a, in ventral and intermediate CNC in wild-types, is reduced in mef2ca mutants. (G,H) dlx3b expression is ectopically expressed in dorsal arch CNC of mef2ca mutants (arrows). (I,J) In contrast, dlx4b expression, restricted to ventral arch CNC, is largely undetectable in mef2ca mutants. The first two arches are numbered.