In vitro loxP site-specific recombination

Cre Recombinase catalyzes the site-specific recombination of DNA between 34-bp loxP sites derived from bacteriophage P1 (Sternberg 1986). The enzyme is a Type I topoisomerase that requires no cofactors or energy to effect recombination. The type of recombination event depends on the relative orientation of the two loxP sites. Tandemly repeated sites cause circularization of the DNA between them, making possible the preparation of plasmid subclones from larger DNA (e.g., Novagen lambda cloning vectors). If the loxP sites are in opposite orientations, the DNA between them is inverted by Cre Recombinase. Two DNA molecules having single loxP sites are joined by the enzyme, making this system useful for targeting sequences into large genomes (Fukeshige 1992, Baubonis 1993). Because the enzyme uses no energy, Cre Recombinase reactions result in an equilibrium that does not favor the accumulation of one product over another. Novagen Cre Recombinase is highly purified from a recombinant source, and is free of contaminating nucleases. It is qualified for in vitro applications, including circularization of plasmids out of loxP-containing lambda vectors. A loxP Control DNA and 10X reaction buffer are included.

References:
Sternberg, N., et al. 1986. J. Mol. Biol. 187, 197. Fukushige, S., and Sauer, B. 1992. Proc. Natl. Acad. Sci. USA 89, 7905. Baubonis, W., and Sauer, B. 1993. Nucleic Acids Res. 21, 2025.

Unit Activity: One unit is defined as the amount of enzyme required to achieve maximal specific site recombination of 0.5 µg test DNA in one hour at 37°C in a 30-µl reaction volume.

Components:

•	250 U	Cre Recombinase
•	1 µg	loxP Control DNA
•	1 ml	10X Cre Buffer