Expression of cyclin proteins during erythroid differentiation of CB CD34⁺ cells.

(A) and (B) Cells were analyzed by bivariate cell cycle analysis. Results are the mean ± SEM from 4 experiments. (C) Scatter density diagrams of bivariate flow cytometric analysis of cell cycle proteins. G0/G1 (2N) and G2/M (4N) phase populations are indicated. Above the solid horizontal lines are cutoffs for positive staining based on the isotype controls. One of 5 representative experiments is shown. (D) Expression of cyclin and cdk proteins determined by immunoblot analysis. Equal amounts of total cell protein were subjected to SDS/PAGE and immunoblotting, with tublin used as control. Results are 1 of 3 representative experiments.