What is the function of the rev gene in lentiviral packaging systems?
HIV-1 mRNA transcripts have sequences that prevent export from the nucleus which therefore prevent translation into protein in the cytoplasm. To over come this block, the Rev protein binds to the RRE sequence and through the binding of other additional nuclear export proteins, facilitates the export of the transcripts into the cytoplasm. Without rev and RRE, there would be no expression of viral proteins. Virapower adds rev in separately (in trans) and out of its native context. Because of this the effeciency of viral particle production is lower. The Trans-Lentiviral Packaging system has rev provided in cis (in its native context) with gag/pro and also provided on an additional plasmid (pTLA1-Rev). This is one of the reasons the Trans-Lentiviral Packaging System is more efficient for packaging the pLKO. 1 vector.