POU4F3 and infection: As shown in Figure 3A,B, in cells of the J1-6d infection scheme, the expression levels of hair cell- specific genes (Myosin7a, Brn3c, Atoh1, and Espin) or one supporting cell-specific gene (P27kip1) were all significantly lower than the cells infected with NC-shRNA (p < 0.01), while there was no significant difference in gene expression between cells from the J1-12d infection scheme and cells infected with NC-shRNA (p > 0.05) (Figure 3B).