Fig. 1.

Integrity of the Six1a DNA-binding domain is required for the proper function of Six1a in vivo. The decrease in neuronal numbers and increases in hair cell numbers, proliferation and cell death normally observed after six1a over-expression are not observed when using mutant constructs. Values represent mean cell counts (± standard deviation) with a sample size of 20 embryos for each experiment. (A) Average number of hair cells and neurons in 3 dpf utricular maculae and SAG. Hair cells and neurons were detected by HCS-1 and HuC immunolabeling, respectively, using confocal microscopy. (B) Quantification of cell proliferation and programmed cell death in otocysts at 28 hpf. Cells labeled with either PhosphoHistoneH3 or activated Caspase3. For cell proliferation and death, only cells within the otocyst were counted. Statistical analyses were performed for both panels with Student’s t test; all comparisons were made to embryos injected with the standard MO control or with six1a mRNA. Comparisons where P < 0.05 were considered statistically significant.