LoxP GFP/RFP ColorSwtich Particles

CRE recombination provides an excellent tool for conditional gene targeting by allowing transgenic animal modeling that links genotypes (alterations in genomic DNA) to biological outcomes (phenotypes).  CRE reporting lentivirus is a very effective method for verifying the performance of CRE-mediated recombination in vivo. It is also a control indicator for verification of CRE lox based systems.   

GenTarget LoxP ColorSwitch CRE reporting lentiviral particles provide a convenient, easy, and fast indicator of CRE recombination efficacy in vivo or in cell culture. These lentiviral particles have been engineered to constitutively express the “LoxP-GFP-stop-LoxP-RFP-Stop” cassette under a super CMV promoter, thereby reporting the presence of CRE enzyme via a color switch mechanism (see the expression cassette scheme below). 

CRE LoxP cassette LoxP GFP/RFP ColorSwitch (Bsd) lentivirus

How it works:

This lentivirus demonstrates a strong GFP fluorescence after infection into any mammalian cells but does not show an RFP fluorescence signal.  Once the CRE protein is present in the nucleus, CRE excises/deletes the DNA fragment between two loxP sites. As a result, the GFP is removed and RFP is expressed, with a resulting switch to RFP fluorescence. The ratio of RFP-expressing to GFP-expressing cells can be easily monitored via fluorescence cell sorting, visualized by microscopy, or the fluorescence intensity may be measured by a fluorometer with GFP and RFP filter sets. See the sample results below.

CRE LoxP sample image LoxP GFP/RFP ColorSwitch (Bsd) lentivirus

Images taken before and 48 hours after the CRE expression particles (CAT#: LVP339) was added into cell culture.

GenTarget provides the CRE reporting lentivirus with different antibiotic selection markers as puromycin, neomycin, or blasticidin. The selection markers are expressed under an RSV promoter (not shown in the scheme above). Therefore, you can easily select the positive transduced cells (expressing the CRE detection cassette) via a specific antibiotic marker, blasticidin (Bsd), Puromycin (puro), or Neomycin (Neo).

The Loxp ColorSwtich particles are provided as 200ul aliquot/vial either in DMEM medium (with 10% FBS and 10x polybrene) or in PBS solution. The particles in PBS solution are good for serum sensitive culture and for hard-to-transduce cell types. Please see product manual for details.

See our Pre-made Color-Swtich CRE reporter cell lines that transformed using this LoxP GFP/RFP lentivirus.

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