Modulation of the unfolded protein response in persistently JEV-infected cell clones. (A) Protein samples were collected from BHK-21 cells infected with JEV at an MOI of 1 at 0 to 36 hr p.i., and from persistently JEV-infected (PI) cell clones cBS6-2 and cBS6-3. Cell lysates were analyzed by Western blotting for p-PERK, total PERK, p-eIF2α, total eIF2α, ATF4, CHOP, BiP, JEV NS3, and the internal control β-actin. Band intensities for BiP and NS3 were determined by densitometry and normalized to those for β-actin. (B) BHK-21 cells and PI cell clones treated with 0.5 μg tunicamycin mL−1 (lanes TUN), or with DMSO, were harvested 24 hr later, and the cell lysates were prepared and determined for protein expression by Western blotting, as described for panel A.