FIG 7.

Integrated stress response inhibition restores NA synthesis in the presence of 6-TG, but NA processing and virion production remain impaired. A549 cells were infected with IAV-PR8 at an MOI of 1. After 1 h, cells were washed and treated with tunicamycin (TM) (5 μg/ml), 6-thioguanine (6-TG) (10 μM), and/or 500 ng/ml ISRIB. (A) At 24 hpi, cell lysates were collected and processed for native SDS-PAGE and immunoblotting using an anti-NA antibody. N-glycosylated forms of NA are indicated as NA-gly, whereas glycosylated NA dimers are indicated as dimers. Actin was used as a loading control. (B) At 24 hpi, cell supernatants were collected, and infectious IAV-PR8 virions were enumerated by a plaque assay. Error bars represent the standard deviations between biological replicates (n = 4). Circles represent biological replicates, and lines represent mean values.