GSK-3 inhibitors yield monopolar and syntelic attachments. DLD-1 cells were incubated with GSK-3 inhibitors for 24 hours then fixed and stained to detect DNA (red), tubulin (green), BubR1 (blue) and centromeres (ACA, red) as indicated. Images represent projections of deconvolved image stacks. (A) Control cell showing examples of bioriented chromosomes. (B) GSK-3 inhibitor treated cell showing that chromosomes near the metaphase plate are bioriented. (C-E) Inhibitor treated cells showing examples of either syntelic attachments (C, Dii, Eii) or monopolar attachments (Di, Ei). Bar is 5 μm when the entire spindle is shown or 1 μm in the enlargements. The cells in C-E were treated with 30 μM SB-415286.