Hygromycin B inhibits synthesis of murine coronavirus RNA

The aminoglycoside hygromycin B inhibits the infection of mouse hepatitis virus (MHV) A59 both in vitro and in vivo. In probing the mechanism by which hygromycin B exerts its antiviral effect, we describe here studies which point to inhibition of viral RNA synthesis as the key step in virus replication which is affected by the drug. Cells which are infected with MHV do not take up higher levels of hygromycin B than do uninfected ones. Comparative assays of MHV replication and MHV protein synthesis in the presence of hygromycin B and another aminoglycoside, neomycin, indicate that hygromycin B is the more-effective antiviral agent and that its antiviral activity likely does not involve phosphoinositide-mediated processes such as those inhibited by neomycin.