Fig. 6.

Absence of KCNQ4 immunoreactivity in OHCs as a first indicator of loss of OHC phenotype. Cochlear sections of WT and BKα^–/– (8 weeks) of different turns were triple-stained for KCNQ4 (green), prestin (red), and DAPI (blue) (A); Kir4.1 (red), synaptophysin (green), and DAPI (blue) (B); and SK2 (red), synaptophysin (green), and DAPI (blue) (C). Note the decline of KCNQ4 in the midbasal but not apical cochlear turn in BKα^–/– mice, whereas prestin, synaptophysin, SK2, and Kir4.1 expression was still normal. (D) KCNQ4 antibody specificity was confirmed by detection of a band at the predicted molecular mass of ≈77 kDa in Western blot in membranes of cochlear tissue (lane 1) and the abolition of the 77-kDa Western signal by preadsorbing the antibody with the antigenic peptide (lane 2). (Bar in A and B = 50 μm; in C = 20 μm.)