Dissociation of NS5 from cell fractions containing West Nile virus-specific polymerase activity.

West Nile virus replication complexes were partially purified from cytoplasmic extracts of virus-infected cells by centrifugation through a 20% glycerol cushion. Numerous cell proteins, as well as the largest nonstructural protein, NS5, were separated from the replication complexes without significant loss of in vitro West Nile virus polymerase activity.