Profile of cell cycle progression of G2/M synchronized cells. A: Upper panel: Two-parameter histogram of the distribution of BPHLacZ cells in G2/M (4N) and G1/S (2N) at different time points after release from nocodazole block. Lower panel: Dot plots of BrDU incorporation in these cells as they progressed through the S phase of the current cycle and the next cycle. B: Upper panel: Allocation of BPHL cells in G1 and G2 phases following release from G2/M block showing an overall sluggish transition of G2/M cells to G1. Lower panel: Incorporation of BrDU in G2/M synchronized BPHL cells shows transition of cells through the S phase. Note low uptake of BrDU by cells with 2N DNA content. C, D: Percentage distribution of BPHLacZ cells (C) and BPHL cells (D) in IG1, IG2, FG1 and FG2. Note slow progression of the subset of BPHL cells in G2/M (checkered bar). Data presented here is a representative of two separate experiments.