Structural and functional analysis of the human immunodeficiency virus type 2 Rev protein

The Rev proteins of the human immunodeficiency virus (HIV) are necessary for expression of viral structural gene products. Site-directed mutations were made within the HIV-2 rev gene to identify functional domains. We observed that similar to HIV-1 Rev, the HIV-2 Rev protein was phosphorylated, albeit to a much lesser extent than was HIV-1 Rev. We also found that like HIV-1 Rev, HIV-2 Rev localized to the nucleus, with a marked accumulation in the nucleolus. Mutations within a stretch of basic residues prevented both nuclear and nucleolar localization. Furthermore, mutant Rev proteins able to localize in the nucleus but unable to localize in the nucleolus were nonfunctional.