Tfap2a regulates maturation of SAG neurons.
(A-L) Images of anti-Isl1 antibody staining in control embryos (A-D), tfap2a-/- mutants (E-H) and hs:tfap2a embryos (I-L) at 37 hpf. Control and hs:tfap2a embryos were heat shocked at 24 hpf. Whole-mount specimens (A, E, I) show dorsolateral (anterior to the left) and indicate planes of cross-section in (B-D), (F-H) and (J-L). Cross-sections are oriented with dorsal up and medial to the left. The otic vesicle is outlined in each image. White arrows indicate the SAG population to help distinguish it from other Isl1+ populations present in some sections. (M) Total number of Isl1+ neurons in hs:tfap2a embryos at 30 hpf following heat shock at the indicated times (n = 10–15 each). (N-P) Cross-sections of a hs:tfap2a specimen at 37 hpf following heat shock at 29 hpf. Planes of section are similar to those shown in (I). (Q-S) Cross-sections of a hs:tfap2a embryo stained for TUNEL positive SAG neurons at 42 hpf. (T) Mean and standard deviation of the total number of Isl1+ SAG neurons at the indicated times in +/+ embryos, hs:tfap2a embryos, tfap2a-/- mutants and tfap2a morphants (n = 7–34 embryos per time point). (U) Mean and standard deviation of the total number of TUNEL positive SAG neurons at the indicated times in control embryos and hs:tfap2a embryos (counted from serial sections, n = 3–6 ears per time point). Asterisks (*) indicate statistically significant differences compared to control embryos.