Lentiviral plus Cre-Lox Service
Creative BioMart Vir-Sci accumulate years of experience in generating Cre-Lox compatible lentivirus for scientists in both academia and industry. By using highly standardized and efficient methods, we permit smart design as well as rapid production of recombinant lentiviral particles with high quality.
Cre-Lox Recombination System
Cre-Lox recombination was initially used to activate gene expression in mammalian cell lines, and is a site-specific recombinase technology. It has been widely used for conditional mutagenesis in biomedical research since the finding that LoxP-flanked chromosomal DNA sequences can be deleted efficiently by this kind of recombination. Cre-Lox recombination involves the targeting and subsequent splicing of a specific DNA sequence in the presence of an enzyme called Cre recombinase. One of the most common Lox sites, known as LoxP, contains two 13-bp palindromic sequences flanking an 8-bp core sequence. The outcome of recombination depends on the orientation of the LoxP sites. For two LoxP sites on the same chromosome, inverted sites will lead to an inversion of the intervening DNA whereas LoxP sites in the same orientation will delete the floxed DNA sequence. In addition, translocation events may be induced by Cre induced recombination if LoxP sites are located on different chromosomes.
Figure 1. Simplified illustration of single polycistronic excisable lentiviral vector and Cre-mediated removal of transgenes. Four reprogramming factors, linked with 2A self-cleaving peptides, are under the control of constitutive or inducible promoter. A LoxP site was introduced within the 3’LTR. Upon provirus formation, the LoxP will be copied to the 5’LTR. Following infection and successfully reprogramming, the intervening transgenes can be deleted in the presence of Cre recombinase.
Features of Single Polycistronic Excisable Lentivirus
There are always concerns regarding the risk of oncogenic transgene reactivation in iPS derived cells. Furthermore, it has been reported that removal of reprogramming factors improves the developmental capacity of iPS cells. Single polycistronic excisable lentivirus thus holds the following advantages when used to generate iPS cells:
- By virtue of the Cre-Lox recombination system, reprogramming transgenes can be deleted in reprogrammed iPS cells.
- Transient expression of Cre recombinase can be achieved by nonintegrating adenovirus, ensuring high safety and efficiency of the deletion events.
- Single polycistronic vector allows single copy integration, thus eliminating the risk of translocation between different chromosomes when performing transgene removal.
Lentiviral plus Cre-Lox Service Advantages
- Different titer levels and flexible production scales
- Highly optimized protocols with high packaging efficiency
- Fast turnaround time to accelerate your research, and urgent service is available
- Strict QC testing to ensure titer
- Ready to use directly upon delivery
- Competitive and favorable price in the market
- Expert technical support
Workflow of Excisable Lentivirus Preparation
The lentiviral plus Cre-Lox service provided by Creative BioMart Vir-Sci ensures ready-to-transduce, excisable and high titer lentiviral preparations at flexible production scales. If you are looking for this type of service please feel free to contact us, our team of experts will work with you to offer the custom service that meets your needs.
References
- Somers, A., et al. Generation of transgene‐free lung disease‐specific human induced pluripotent stem cells using a single excisable lentiviral stem cell cassette. Stem cells. 2010, 28(10): 1728-1740.
- Papapetrou, E. P.; Sadelain, M. Generation of transgene-free human induced pluripotent stem cells with an excisable single polycistronic vector. Nature protocols, 2011, 6(9): 1251-1273.