K562 PCNA-HH-CAT and PCNA-HN-CAT stable transfectant cell cycle synchronization and transcription analysis. (A) Flow cytometry analysis of mimosine-arrested K562 PCNA-HH-CAT cells (top), thymidine-blocked cells (middle), and nocodazole-inhibited cells (bottom). The distribution of DNA contents was determined by FACScan. Percentage of G1, S-phase, and G2 × M cells in each synchronized cell fraction is shown in each inset. (B) Flow cytometry analysis of mimosine-arrested K562 PCNA-HNCAT cells (top), thymidine-blocked cells (middle), and nocodazole-inhibited cells (bottom). The distribution of DNA contents was determined by FACScan. Percentage of Gl, S-phase, and G2 × M cells in each synchronized cell fraction is shown in each inset. (C) Hybridization of K562 PCNA-HH-CAT nascent nuclear transcripts to PCNA, CAT, and GAPDH DNA probes. (D) Hybridization of K562 PCNA-HN-CAT nascent nuclear transcripts to PCNA, CAT, and GAPDH DNA probes. (E) Quantitation of K562 PCNA-HH-CAT nascent PCNA and CAT transcripts normalized with nascent GAPDH transcripts, respectively. (F) Quantitation of K562 PCNA-HN-CAT nascent PCNA and CAT transcripts normalized with nascent GAPDH transcripts, respectively.