Cre Recombinase is a tyrosine recombinase enzyme derived from the P1 Bacteriophage. The enzyme uses a topoisomerase I like mechanism to carry out site specific recombination events. The enzyme (38kDa) is a member of the Integrase family of site specific recombinase and it is known to catalyse the site specific recombination event between two DNA recognition sites (loxP sites). This premade lentivirus coexpresses Cre and mCherry under the control of the UBC promoter with puromycin as a selection marker.