Figure 4

Overexpression of pDNAJB6 promotes the formation of autophagosomes and progeny virion production in PCV2-infected cells. A, B Western blot analyzes of pDNAJB6 protein levels in PK-15 cells with pDNAJB6 overexpression using anti-Flag antibodies (A) or anti-DNAJB6 antibodies (B). PK-15 are the cells without transfection, PK^V the cells transfected with blank vector, PK^pDNAJB6 the cells transfected with the vector expressing Flag-pDNAJB6. C Cell viability of cell lines stably overexpressing pDNAJB6. D, E Overexpression of pDNAJB6 promotes PCV2 progeny virion production. Wild-type PK-15, PK^V and PK^pDNAJB6 cells were infected with PCV2 (MOI = 5) for 48 h. PCV2 Cap were detected by Western blot (D). PCV2 titers were determined by TCID₅₀ assay (E). F, G Overexpression of pDNAJB6 promotes the accumulation of autophagosomes induced by PCV2 Cap protein or PCV2 infection in PK-15 cells. PK-15 and PK^pDNAJB6 cells that stably express EGFP-LC3 were infected with PCV2 (F) or transfected with pCI-Cap plasmid (G) for 24 h. Scale bar = 10 μm. The right panel graph shows the number of autophagosomes by taking the average number of green puncta in 60 cells. Results are shown as the mean ± SD (n = 3). *p < 0.05 versus wild-type PK-15 cells with the same treatment.