Figure 4. NICD-expressing inner hair cells show morphology changes and abnormal P27KIP1 expression at P11.

A–D. Paraffin sections from Gfi1-NICD cochlea and littermate controls at P11. A′-D′ show higher power views of the inner hair cells, which demonstrate morphological and molecular changes due to Notch activation. The changes in the inner hair cells in the Gfi1-NICD mutants (B,C,D and B′C′,D,) include weaker MYO6 expression, lack of the normal flask-like shape, more basally positioned nulcei, and nuclear P27KIP1 expression normally only observed in supporting cells at this time. Scale bar in D = 100 microns for A–D, and in D′ = 25 microns for A′–D′.