Genome of HIV-1 and the evolution to third generation of lentiviral vector systems
A detailed description of figure representing genome of HIV-1 and the evolution to third generation of lentiviral vector systems.
Figure 1: (A) Genetic organization of HIV genes, which contains the common retroviral genes (i.e., LTRs, psi signal, and gag, pol, and env genes); the gag gene overlaps slightly with pol. HIV-specific accessory gene vif overlaps with the end of pol, vpr overlaps with the end of vif, and vpu overlaps with the beginning of env. Nef overlaps with the end of env and the beginning of the 3’LTR. The regulatory genes tat and rev are splice products consisting of a first part from the vpr/vpu region and a 3’ part from the end of env.
(B) Gene sequence for the 1st generation of lentiviral vector. This system consists of a transfer/vector plasmid and two helper/packaging plasmids. The transfer/vector plasmid consists of a 5’LTR, the psi signal, the transgene, and a 3’LTR. One helper/packaging plasmid is alike to (A); but the psi signal and env gene have been removed, and the 3’LTR replaced with poly A. The other helper/packaging plasmid contains a CMV promoter, and env gene pseudotyped to vsv-g, and a 3’ poly A
(C) Gene sequence for the 2nd generation of lentiviral vector. This system consists of a transfer/vector plasmid and two helper/packaging plasmids. This system is identical to (B), with the exception that the HIV accessory genes (vif, vpr, vpu, and nef) have been removed. The second helper/packaging plasmid is identical to (B).
(D) Gene sequence for the 3rd generation of lentiviral vector. This system consists of a transfer/vector plasmid and three helper/packaging plasmids. The transfer/vector plasmid includes a chimeric 5’ LTR, the psi signal, and the transgene. Parts of the 3’ LTR have been deleted. The first helper/packaging plasmid is identical to (C) and consists of 5’ LTR, gag, pol, and 3’ poly A; but the regulatory genes (tat, rev) have been removed. The second helper/packaging plasmid is identical to (B) with CMV promoter, env/vsv-g, and 3’ poly A. The third plasmid consists of a CMV promoter, rev regulatory gene, and a 3’ poly A.