FIG 8.

SUMO-1 modification promoted EV71 replication. 293T cells (7 × 10⁶) were transfected with HA–SUMO-1, Myc-Ubc9, or empty vector in 100-mm dishes. At 24 h posttransfection, the cells were infected with EV71 (MOI = 10) for 18 h. One of the dishes with no transfection was used as the control. Immunoprecipitation and immunoblot analyses were performed with the indicated antibodies. (A) SUMOylation and ubiquitination assay by immunoprecipitation of 3D in cells with elevated SUMO-1 after EV71 infection. (B) Immunoblot analysis of cell lysis during infection. Anti-VP1, anti-3D, and anti-β-actin antibodies were used to detect the expression of VP1, 3D, and β-actin during infection. Anti-myc antibody was used to detect the expression of Ubc9. SUMO-1- and ubiquitin-modified 3Ds are indicated by brackets and 3CD by an arrow. (C) Growth curves of EV71 produced from transfected 293T cells in RD cells. 293T cells were transfected with HA–SUMO-1, Myc-Ubc9, or empty vector for 24 h, followed by infection with EV71 at an MOI of 10 for 18 h. The cells were harvested at the indicated times postinfection to plot the growth curves. The data are presented as means ± standard deviations obtained from the results of three independent experiments. Significant differences were determined using the Student t test (*, P < 0.01).