GSK-3 inhibitors delay chromosome alignment. DLD-1 cells expressing a tagged GFP-Histone H2B were incubated in the presence or absence of small molecule GSK-3 inhibitors then analysed by time-lapse microscopy. (A) Control cell showing normal mitosis. (B) SB-415286-treated cells. While cell a completes mitosis normally, chromosome alignment in cell b is delayed (see arrows) and anaphase is initiated despite one unaligned chromosome (see *). (C) Box plot measuring time from prophase to metaphase and metaphase to anaphase for at least 42 cells. (D) Box plot measuring time taken from nuclear envelope breakdown (NEB) to anaphase onset. Values taken from at least 41 cells.