Figure 5
S phase accumulation promotes PCV2 replication. A PK15 cells, 148PK15P53−/− cells, or 813PK15P53m/m cells were cultured without serum for 48 h to synchronize at G0/G1 phase, followed by PCV2 (MOI = 1) or mock-infection. At 18 h post-infection, cells were stained with propidium iodide and applied to flow cytometry analysis. B Cells were synchronized in G1/S phase by 2 mM double-thymidine block for 12 h to release into the S phase. Then the cells were infected with 1 MOI PCV2 for 18 h and applied to flow cytometry analysis. C Cells were synchronized in G2/M phase by treatment with 100 ng/mL of nocodazole for 16 h. Then the cells were infected with 1 MOI PCV2 for 18 h and applied to flow cytometry analysis. D PCV2 ORF1 DNA levels were determined by qPCR at 18 h after infection (MOI = 1) in the cells. The data are mean ± SEM of three independent experiments. **p < 0.01 versus WT cells released from G1/S phase group. # p < 0.05, ## p < 0.01 versus WT cells released from the same phase. E Western blot analysis of PCV2 Cap levels in the WT cells released from different synchronization treatments as above. F Western blot analysis of PCV2 Cap levels in WT PK15 cells, 148PK15P53−/− cells, or 813PK15P53m/m cells released from G1/S phase synchronized cells. Data represent three independent experiments.