Fig. 5.

Notch signaling directs INC subtype specification. (A,B) Wild-type distribution of alpha- and beta-INCs. (C,D) High doses of HMM^mut mRNA increase both INC subtypes, but favor beta-INC differentiation, as determined by ae1 and pendrin-GFP staining or by atp6v1b1 localization (not shown). (E) Notch signaling was titrated either with two decreasing doses of HMM^mut to block signaling or three increasing doses of ICD to promote signaling, and then embryos were assayed for proportions of alpha- and beta-subtypes by confocal microscopy and cell counting. Cells were counted from at least three confocal fields from several embryos, typically eight. Raw INC subtype numbers were then converted into percentages and arcsine transformed. Two-tailed t-tests indicated significant differences between each dose (P≤0.05) except for the two HMM^mut doses, which were not significantly different (the two leftmost columns). Error bars indicate + s.d. Scale bar: 40 μm.