Fig. 3

Defective expression of NC SoxE family genes in foxd3^zdf10;tfap2a^low double mutant embryos. (A,B,D-F) Dorsal views with anterior to the top of 6, 5 and 9 somite stage (s) embryos. (C) Lateral views with anterior to the left of 30 hpf embryos. (A) NC sox9b expression is severely depleted in foxd3^zdf10;tfap2a^low double mutants at the 6 somite stage, but is retained in the non-NC-derived otic placode (asterisks). (B) NC sox9b expression remains reduced in both single mutants, whereas NC expression is undetectable in double mutants by the 9 somite stage. (C) NC sox9a expression in the branchial arches (arrows) is absent in double mutant embryos. (D) There are slight reductions in NC sox10 expression in foxd3^zdf10 and tfap2a^low single mutants at the 5 somite stage, whereas in double mutant embryos NC sox10 expression is much more reduced. (E) By the 9 somite stage, NC sox10 expression is undetectable in double mutants. (F) In contrast to SoxE gene expression, NC foxd3 expression is maintained in foxd3^zdf10;tfap2a^low double mutant embryos, demonstrating that NC induction occurs.