Alternative Roles of Neuraminidase in Influenza a Viral Propagation

Alternative Roles of Neuraminidase in Influenza a Viral Propagation

Influenza A is an envelope virus containing a segmented negative RNA genome. The viral envelope has two major surface glycoproteins, Hemagglutinin (HA) and Neuraminidase (NA) of which there are 16 and 9 subtypes respectively. While HA has been well characterized and shown to be essential for viral fusion and entry into host cells, the functional roles of NA in viral replication are much less understood. Some previous reports suggest that NA exerts its primary role during viral exit from the cell by enzymatically cleaving sialic acid and facilitating the release of viral particles from the host cell. Indeed this role is supported by the observation, that NA-defective viruses, or wild type (WT) viruses in the presence of NA inhibitors, form aggregations on the apical surface of the cells.