Pre-made lentiviral particles bicistronically express two individual proteins: firefly luciferase and nuclear permeable CRE recombinase, under the same suCMV promoter. A RFP-Puromycin fusion dual marker was expressed under RSV promoter, which allow to select the positive transduced stable cells for long term culture via RFP cell sorting or via antibiotic selection.

Both lucifease and CRE are highly active, best for both enzymes' assays In vivo or In vitro. CRE protein, from bacteriophage P1, catalyzes recombination between 34 base pair target sequences, named lox sites. CRE lentiviral particles can catalyze the jointing event In Vivo in the presence of lox sites. This nuclear permeant CRE (NLS-CRE) increases the recombination events in vivo. Purified CRE enzyme can joint individual plasmids containing lox sites.

Luciferae and NLS-CRE are constitutively expressed in high level, and optionally, also can be used as tetracycline inducible expression as desired. Luciferase and RFP provide the convenient, realtime monitoring signals.   

This particles is concentrated and buffer changed into PBS solution, best suitable for hard-to-transduced cell lines, or serum-sensitive cell lines and in vivo application.