The rev gene of visna virus is required for productive infection

To assess the role of the animal lentivirus rev regulatory gene product in the life cycle of visna virus, we introduced mutations into the functional fourth exon of the rev gene of visna virus. Cultured cells transfected with a full-length clone of visna DNA produce infectious virus but visna DNA with mutations in rev does not. The documented requirement for a functional rev gene in productive infections establishes the essential role of this gene in the replication of an animal lentivirus.