Aurintricarboxylic acid inhibits the early stage of vaccinia virus replication by targeting both cellular and viral factors.

Aurintricarboxylic acid (ATA) has been shown to inhibit the replication of viruses from several different families, including human immunodeficiency virus, vesicular stomatitis virus, and the coronavirus causing severe acute respiratory syndrome. This study characterizes the inhibitory effect of ATA on vaccinia virus replication in HeLa, Huh7, and AD293 cells. Vaccinia virus replication is significantly abrogated upon ATA treatment, which is associated with the inhibition of early viral gene transcription. This inhibitory effect may be attributed to two findings. First, ATA blocks the phosphorylation of extracellular signal-regulated kinase 1/2, an event shown to be essential for vaccinia virus replication. Second, ATA inhibits the phosphatase activity of the viral enzyme H1L, which is required to initiate viral transcription. Thus, ATA inhibits vaccinia virus replication by targeting both cellular and viral factors essential for the early stage of replication.