Fig. 4. CDK11 depletion results in mitotic arrest. (A) Most CDK11-depleted mitotic cells retain cyclin B despite sister chromatid separation. CDK11 RNAi or control RNAi cells were stained for cyclin A (green), cyclin B (red) and DNA (DAPI) 48 hours after transfection. A portion of these cells were treated with nocodazole for six hours before harvesting. Cyclin A and cyclin B content was analyzed by immunofluorescence in 130-250 mitotic cells from each group in a representative experiment. (B) CDK11 depletion results in mitotic arrest with BubR1 accumulation to the kinetochores. HeLa cells were analyzed by indirect immunofluorescence 48 hours after transfection with CDK11 RNAi or control plasmids using antibodies to BubR1 (red) and CREST (green). DNA is stained with DAPI (blue). Bars, 5 µm.