EF1α-Cre-GFP-Puro Lentivirus

Insertion of the viral genome into the host genome follows the following steps: (1) binding to the host cell, membrane fusion and capsid entry, (2) reverse transcription of viral RNA into DNA, (3) nuclear import and (4) proviral integration. Integration is mediated by IN encoded in the viral pol gene and cleaved by PRO of the Gag-Pol polyprotein. The integration process consists of several steps: modification of the vector 3′ end, opening of the host genome and insertion of the viral DNA, gap repair and ligation. Genomic integration is a relatively inefficient process with inconsistent integration sites within the host genome. It has been shown previously that lentiviruses, unlike other retroviruses, preferentially integrate into active transcriptional units, with integration sites reportedly influenced by chromatin accessibility, cell cycle effects and tethering mechanisms. Indeed, studies have shown that lens epithelium-derived growth factor (LEDGF/p75), a host cell protein, is able to target the pre-integration complex to DNA and promote integration. After integration, the 5′ LTR acts as a promoter, driving transcription of the viral genome using the host transcription machinery. First, several viral proteins will be synthesized and, in conjunction with cis-acting elements, finely regulate transcription and splicing efficiency, driving the continuous production of all viral proteins and unspliced viral mRNA in the same viral genome. The process from viral entry into the host cell to the entry of the viral genome into the nucleus are some of the important features required to make the virus a gene therapy tool. If these endogenous lentiviral abilities are clearly beneficial for clinical transfer to gene therapy, their replication capacity must be inhibited to ensure the safe use of lentiviruses. In fact, since lentiviruses divert host machinery for their life cycle and replication, they rapidly induce host cell apoptosis and lead to the abnormal release of new lentiviral particles.