A positive-sense RNA genome can be directly translated into viral proteins. In other flaviviruses, such as the similarly sized West Nile virus, the RNA genome genes encode seven nonstructural proteins and three structural proteins. The structural proteins encapsulate the virus. The replicated RNA strand is held within a nucleocapsid formed from 12-kDa protein blocks; the capsid is contained within a host-derived membrane modified with two viral glycoproteins. Replication of the viral genome would first require creation of an anti-sense nucleotide strand