Expression of cyclin B1 and CDK1 proteins in polyploid MKs. Experiments were performed as described in Fig 6. Western blot analysis was performed with a polyclonal antibody directed against cyclin B1 and an MoAb against CDK1. The experiments were performed with the proteins derived from the same number of cells (a and c) or with the same amounts of proteins (b and d). Expression of cyclin B1 in MKs (a and b). (a) Lane 1, UT-7 cell line transfected with c-mpl(UT-7-c-mpl) and grown with PEG-rhuMGDF; lane 2, UT-7-mpl grown with PEG-rhuMGDF and synchronized with nocodazole; lane 3, 2N-4N MKs; lane 4, >4N MKs. (b) Lane 1, 2N-4N MKs; lane 2, >4N MKs. Expression of CDK1 in MKs (c and d). (c) Lane 1, UT-7-c-mpl cell line as positive control; lane 2, 2N-4N MKs; lane 3, >4N MKs. (d) Lane 1, 2N-4N MKs; lane 2, >4N MKs.