Figure 7.

PEDV-Envelope and ORF3 proteins inhibit promoters’ activation of SLA-DR. (A) HEK-293T cells were transfected with plasmids encoding S2, M, N, E and ORF3 for 48 hours. Next, cells were fixed and stained with anti-C-MYC tag Mab and visualized by secondary antibody. (B) HEK-293T cells were transfected with plasmids encoding S2, M, N, E and ORF3, along with firefly luciferase reporter plasmids bearing promoters of SLA-DRα and SLA-DRβ for 48 hours. Control plasmid pRL-TK was co-transfected to normalize transfection. Next, cells were harvested for evaluation of luciferase activity. HEK-293T cells transfected with empty vector and luciferase reporters were included as controls. Error bars represent variation from at least three independent experiments. Significant differences of luciferase activity between indicated groups was marked by ***, P < 0.001. (C) Schematic illustration of truncations of PEDV-E protein. HEK-293T cells were transfected with plasmids encoding full length PEDV-E protein and truncations, along with firefly luciferase reporter plasmids bearing promoters of SLA-DRα and SLA-DRβ for 48 hours. Control plasmid pRL-TK was co-transfected to normalize transfection. Next, cells were harvested for evaluation of luciferase activity. HEK-293T cells transfected with empty vector and luciferase reporters were included as controls. Error bars represent variation from at least three independent experiments. Significant differences of luciferase activity between cell groups transfected with E truncations and empty vector was marked by ***P < 0.001, or “ns.” means nonsignificant.