Fig. 3.

LIN28B overexpression promotes supporting cell de-differentiation. Cochlear organoid cultures were established from stage P5 iLIN28B transgenic mice and control littermates that lacked the LIN28B transgene. Cochlear organoid cultures were maintained as outlined in Fig. 2A. P27-GFP transgene expression was used to monitor postmitotic supporting cells in A and B. (A) Representative BF and green fluorescent images of p27-GFP expression in LIN28B overexpressing and control organoid cultures at 5 and 13 d of expansion and 1 and 7 d of differentiation. (B) Percentage of p27-GFP⁺ organoids in A (mean ± SD, n = 7, two independent experiments). (C) qRT-PCR analyzing supporting cell-specific (S100a1, F2rl1, Ano1, Cybrd1), prosensory cell-specific (Fst, Fat3, Hmga2, Trim71) mRNA expression in control (Ctrl, blue bar) and LIN28B overexpressing (iLIN28B, red bar) organoids at 7 d of expansion. Emx2 and Isl1 served as controls (mean ± SD, n = 3, from one representative experiment, three independent experiments). n = animals analyzed per group. Two-tailed, unpaired Student’s t test was used to calculate P values.