The two bipartite basic amino acid sequences in the p17 C-terminus play an important role in NBV replication in DemKT1 cells.

(A, C) Viral titers of rsMB/p17-null in DemKT1 cells expressing wild-type and mutant p17 proteins (A) or FLAG-tagged wild-type and mutant p17 proteins (C). Cells were infected with rsMB/p17-null at an MOI of 0.1 PFU/cell (n = 3) at 24 h post-transfection, and viral titers were determined by plaque assay at 24 h post-infection. Results are expressed as the mean of three samples. Error bars indicate standard deviations. Significant differences compared to the vector control are indicated by asterisks. *p < 0.05 (Dunnett’s test). (B, D) Electrophoretic analysis of viral proteins in rsMB/p17-null-infected cells expressing wild-type and mutant p17 proteins (B) or FLAG-tagged wild-type and mutant p17 proteins (D). Wild-type or mutant p17 expression plasmids were transfected into DemKT1 cells and infected with rsMB/p17-null at an MOI of 1 PFU/cell at 10 h post-transfection. Cells were lysed at 16 h post-infection. Cell lysates were subjected to immunoblotting using antibodies raised against NBV proteins or β-actin.