FIG 2.

The knockdown of HDAC1 expression promotes IAV infection. (A) A549 cells (2 × 10⁵) were transfected with indicated concentrations of nontargeting control (CT) siRNA or HDAC1-targeting (HD1) siRNA for 72 h. Total cell lysates were prepared, and HDAC1 and PDI were detected by WB. (B to D) A549 cells were transfected with 10 nM CT siRNA or HD1 siRNA for 72 h. The cells were then infected with PR8 at an MOI of 0.5, and the culture medium and the cells were harvested separately after 2, 6, 12, and 24 h of infection. The virion yield in the culture medium was measured by WB of NP (B) and by microplaque assay (C). The data presented are means ± the standard errors of the means of three independent experiments; the P value was calculated by using two-way ANOVA. (D) Total lysates of the cells were prepared, and HDAC1, PDI, and NP were detected by WB. (E) A549 cells transfected with CT or HD1 siRNAs, as described above, were infected with PR8 at an MOI of 0.1 in the presence of 0.1 μg of trypsin/ml, and the virion yield in the culture medium was measured by microplaque assay after 24 and 48 h. The virion yield from respective CT siRNA samples was considered to be 1-fold for comparisons to HD1 siRNA samples. The data presented are means ± the standard errors of the means of three independent experiments; the P values were calculated using one-way ANOVA. (F) A549 cells were transfected with no siRNA, CT siRNA, or HD1 siRNA for 72 h. The cell viability was determined using an MTT assay. MW, molecular weight; ns, not significant.