FIGURE 6.

Nucleocapsid proteins of porcine alpha-coronaviruses suppress the function of porcine cell-derived zinc-finger antiviral protein (ZAP). (A) Schematic representation of the procedure of a luciferase-based assay to measure the activities of pZAPL and -S in the presence of the various pCoV-N. (B) To assess the ability of pCoV-N to antagonize ZAP activity, pGL3-Luc-ZRS was co-transfected with pZAPS or -L and the indicated pCoV-N expressing plasmids. A plasmid expressing Renilla luciferase, pRL-TK, was used to normalize transfection efficiency, and an empty pCAGGS vector (EV) was used as a control plasmid. At 48 hpt, cells were lysed, and luciferase activity was measured. Relative fold inhibition is fold inhibition (described in “Materials and methods”) in the presence of the respective pCoV-N divided by fold inhibition of cells with EV. Data shown are the means ± SD of three independent measurements (Student’s t-test, **p < 0.005, ****p < 0.00005). (Bottom) SDS-PAGE/western blot showing expression of pZAPL in each condition.