MMLV retroviral gene expression vector system is a very efficient system that can stably integrate foreign genes into mammalian cell genome. It is also a very popular gene transduction method in iPS cell preparation.
MMLV retroviral vector is derived from Moroni murine leukemia virus and belongs to retrovirus family. The genome of wild type retrovirus is linear double positive stranded RNA.
After the construction of the recombinant vector of MMLV retrovirus, it was transfected into the packaging cells together with the auxiliary plasmid. In packaging cells, DNA fragments located between two long terminal repeats (LTRs) will be transcribed into RNA, which will be packaged into virus particles by viral proteins expressed by auxiliary plasmids. The packaged live virus will be released into the supernatant, which can be directly collected or further concentrated to transfect target cells.
When the virus transmits to the target cell, the viral RNA released into the host cell is reverse transcribed into DNA with the help of reverse transcriptase, and then randomly integrated into the genome of the host cell. In viral vectors, DNA fragments and viral genomes located in the two LTRs will be stably integrated into the genomes of target cells.
Through modification and optimization, our MMLV retroviral vector deleted genes related to virus packaging and transduction (these genes are expressed by auxiliary plasmids for virus packaging). Therefore, the viruses produced by retroviral vector packaging are replication defective (they can only transduce target cells but not self replicate), with very high biological safety.
For more information on MMLV retroviral gene expression vectors, please refer to the following literature.