Cre recombinase

Cre recombinase is a site-specific recombinase isolated from the P1 bacteriophage that catalyzes recombination between two 34-bp loxP sites. It is widely used for knockout and knockin studies: the DNA sequence located between two tandem repeats of loxP sites can be excised to create a deletion mutant, or a plasmid containing a single loxP site can undergo site-specific integration into a genome containing loxP to create an insertion mutant.

We have focused on providing tools for the efficient delivery of a burst of footprint-free Cre recombinase into cultured mammalian cells using a variety of technologies:

• RLPs—RNA lentiviral particles (RLPs) consist of biologically active Cre recombinase and ZsGreen1 mRNAs packaged into nonintegrating, virus-like particles. These Cre-ZsGreen1 RLPs are generated using a novel packaging technology that employs a phage RNA-binding protein to load multiple mature mRNA molecules per particle. RLPs deliver mature mRNA that leads directly to transient protein expression. There is no waiting for promoter-driven translation and there is no genomic integration. These VSV-G pseudotyped particles are capable of transferring RNA into dividing and nondividing cells. The high purification level of these lentiviral particles allows transduction of primary cells and immortalized cell lines.
• Gesicles—Cre Recombinase Gesicles are cell-derived nanovesicles used to deliver active Cre recombinase protein directly into target cells. When applied to your target cells, gesicles fuse with the plasma membrane and deliver a temporary dose of Cre recombinase protein, which facilitates recombination at loxP sites contained within the cell.
• AAV—Adeno-associated viruses (AAVs) are commonly used for gene delivery in vivo due to their mild pathogenicity. In recombinant form, these viruses can direct expression without permanently integrating into the host genome. AAVpro Helper Free Systems are kits for the preparation of high-titer AAV particles without the need for a helper virus.