Sox2 overexpression at the early bell stage and in 293T cells. Mouse tooth germs at early bell stage were cultured for 2 days with a (A‐a, a’, b, c) control or (A‐d, d’, e, f) Sox2‐overexpressing lentivirus. Sox and Claudin10 coexpression patterns in the (A‐a, a’) control and (A‐d, d’) Sox2 overexpression groups, PCNA expression patterns in the (A‐b) control and (A‐e) Sox2 overexpression groups, and Laminin5 expression patterns in the (A‐c) control and (A‐f) Sox2 overexpression groups were analysed. B, Western blot and (C) RT‐qPCR analyses of control and Sox2 overexpression in 293T cells. D, Relative luciferase activity and (E) ChIP assays were used to confirm the binding of Sox2 with the Claudin10 promoter. Scale bar = 100 µm (A‐a’, b, c, d’, e, f), 200 µm (A‐a) or 1 mm (A‐d)