Tfap2a regulates the number of transit-amplifying SAG precursors.
(A-I) Cross-sections (medial left, dorsal up) at the level of the utricular macula showing neurod expression in +/+ control, tfap2a mutants and hs:tfap2a embryos. Wild-type and hs:tfap2a embryos were heat shocked at 24 hpf. Disruption of tfap2a leads to accumulation of excess TA cells whereas tfap2a overexpression decreases the number of the TA cells. The outer and inner edges of the otic vesicle are outlined in each image. (J) Mean and standard deviation of the total number of neurod positive SAG precursors for the genotypes and conditions indicated in the color key (counted from serial sections, n = 3–6 ears per time point). Asterisks (*) indicate significant differences from control specimens.