Visualization of H2B-GFP and α-tubulin-RFP fluorescence in U2OS osteosarcoma cells allowed us to follow the dynamics of chromosome congression and mitotic spindle organization in untreated live cells (Figure 4d, Supplementary material, video 3) or cells treated with SM15 (Figure 4e, Supplementary material, video 4). Here, H2BC21 is linked to osteosarcoma.