Production of multicistronic HIV-1 based lentiviral vectors

In the last decade lentiviral gene transfer vectors have gained significant place both in basic science and gene therapy applications. A number of gene transfer applications would benefit from vectors capable of expressing multiple genes. This chapter focuses on production of bicistronic and tricistronic lentiviral vectors based on the internal ribosomal entry site (IRES) sequence of encephalomyocarditis virus (EMCV) and/or foot-and-mouth disease virus (FMDV) cleavage factor 2A. Multigene vectors produced high titer viral particles and were able to simultaneously express two or three transgenes in transduced cells. The level of expression of individual transgenes varied depending on the transgene itself, its position within the construct, the total number of transgenes expressed, the strategy used for multigene expression, and the number of copies of proviral insertions.