BrdU immunocytochemistry of utricular epithelial cell cultures. (a) Control cultures and cultures infected with lentivirus (20 multiplicity of infection) targeting NC, shSTOX1, vector‐control, STOX1 over‐expression lentivirus, respectively. BrdU was added to cultures at 24 h, and cultures were fixed at 48 h for immunocytochemistry. Antibody against mouse IgG served as negative control for primary antibody. (b, c) Bar graphs indicating proportion of BrdU‐positive cells relative to total cells. Note that numbers of BrdU‐positive cells were greatly reduced by shSTOX1 and significantly increased by over‐expression of STOX1. Data shown as means ± SD (n = 3, **P < 0.01 versus pairing negative control, **P < 0.01 versus pairing vector‐control). Scale bar = 100 μm.