(a) Western blot analysis of dual luciferase reporter lysates. The same amount of lysate was analysed, which corresponds to one luciferase reading. (b–c) Dual luciferase reporter assay using UW228 (b, orange) or ONS-76 (c, purple) cell lines transfected with corresponding Atoh1 mutants and Atoh1-specific firefly reporter. n = 46 in duplicates. (d–f) in vitro proliferation assay using medullospheres of DAOY (d, blue), UW228 (e, orange), or ONS-76 (f, purple) stably infected cell lines. n = 3 in triplicates. Y78 = Atoh1 GFP WT, Y78F = Atoh1 GFP Y78F, Y78D = Atoh1 GFP Y78D; *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001, ns denotes p>0.05.