(A) Yield of induced neurons for different conditions, including control with 3 factors (3F [Brn2, Ascl1, and Myt1l]), 3FDD, and 3FDDRR counted by MAP2+ cells at 17 dpi over number of cells seeded. n = 6 or 7 independent conversions per condition. Mean ± SEM; one-way ANOVA.
(B) Yield of induced dopaminergic neurons (iDANs) for different conditions, including control with 5 factors (5F [Brn2, Ascl1, Myt1l, Lmx1A, and FoxA2]), 5FDD, and 5FDDRR counted by MAP2+ cells at 17 dpi. n = 6–8 independent conversions per condition. Mean ± SEM; one-way ANOVA.
(C) Yield of induced inner ear hair cells (iHCs) for different conditions, including control with 3 factors (3F [Brn3C, Atoh1, and Gfi1]), 3FDD, and 3FDDRR counted by Atoh1::nGFP+ cells at 17 dpi. n = 3–16 independent conversions per condition. Mean ± SEM; one-way ANOVA.
(D) 3F-iHCs and 3FDD-iHCs immunostained with Myosin VIIa at 17 dpi. Scale bars represent 100 μm.
(E) Yield of iMNs generated from adult tail tip fibroblasts with 6F, 6FDD (both conditions with RepSox), and 6FDDRR at 28 dpi. n = 4–9 independent conversions per condition. Mean ± SEM; one-way ANOVA.
(F) Yield of iMNs generated from Hb9::GFP+ adult mouse muscle explants at 28 dpi. n = 4 or 5 independent conversions per condition. Mean ± SEM; unpaired t test.
(G) Yield of iMNs generated from human fibroblasts with factors alone (7F) or 7FDD (both conditions with RepSox), counted by MAP2+ cells at 35 dpi. n = 4–6 independent conversions per condition. Median ± interquartile range is shown; Mann-Whitney test.
(H) Percentage of multipolar iMNs derived from primary human fibroblasts at 35 dpi. n = 3 independent conversions per condition. Mean ± SEM; unpaired t test. (I and J) Step voltage depolarizations result in functional sodium and potassium channels in human 7F (I) or 7FDD-iMNs (J) at 35 dpi.
(K and L) Action potentials evoked by step current injection in current-clamp configuration for human 7F (K) or 7FDD-iMNs at 35 dpi (L).
(L) Model of topoisomerase-mediated reprogramming through hypertranscribing, hyperproliferating cells.
Significance summary: p > 0.05 (ns); *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001; and ****p ≤ 0.0001.