Cre/loxp

Flp/FRT is a system analogous to the cre/loxP system. Flp is an yeast enzyme that recognizes FRT sites. If two FRT sites have a parallel orientation, the DNA segment between these sites will be deleted by the action of the Flp recombinase. 

Classical global knockouts may have a developmental or lethal phenotype and thus preclude the analysis of the phenotypic consequences of the lack of a gene in specific tissues in adult animals. With the development of the cre/loxP and flp/FRT systems, it has become possible to excise defined DNA fragments from the genome of specified cells. Cre and Flp are bacterial and yeast recombinases, respectively, which recognize loxP and FRT sequences, respectively. The most common... 

Muller W, Testa G, Roers A Mast cell-specific Cre/ loxP-mediated recombination in vivo. Transgenic Res 2008 17 307-315. 30... 

Figure 4.3. Univector plasmid fusion system. Cre- loxP mediated site-specific recombination fuses the pUNI and pHOST plasmids at the loxP site. As a result, the gene of interest is placed under the control of the pHOST promoter and fused to any Tag sequences present in the pHOST plasmid.

Gopaul, D. N., Guo, F. and Van Duyne, G. D. (1998). Structure of the Holliday junction intermediate in Cre-loxP site-specific recombination. EMBO J. 17, 4175-4187. 

A widely used inducible system in the mouse is the bacteriophage Pl-derived Cre-LoxP system (25). The site-specific Cre recombinase recognizes specifically 34 bp loxP sites. Generating mice that harbor a DNA sequence flanked by two loxP sites and... 

Analogously to the Cre-LoxP system, the 34 bp Flippase recognition target (FRT) sites are recognized by the Flippase recombination enzyme (FLP) derived from Saccharomyccs cerevisiae (28). The FLP-FRT recombination system is also utilized for the inducible genetic manipulation of the mouse genome (29, 30). 

Stable Integration of Cre/loxP Conditional shRNA Vectors Into ES Cells by RMCE and Generation of Knockdown Mouse Lines... 

Hitz C, Wurst W, Kuhn R (2007) Conditional brain-specific knockdown of MAPKusing Cre/ loxP regulated RNA interference. Nucleic Acids Res 35 e90... 

Fig. 3. Representation of (A) the two basic types of targeting vectors, (B) positive and negative selection markers, (C) the hit-and-run approach to introduce subtle mutations, and (D) the CRE/loxP recombinase system.

Van Duyne, G.D. (2001) A structural view of Cre-loxP site-specific recombination. Annu. Rev. Biophys. Biomol Struct. 30, 87-104. 

Since the reaction doesn t require accessory protein factors and can be performed in vitro with a variety of DNA substrates, the Cre-loxP system is much used in genetic engineering.583 584 A pair of related integrase subunits known as XerC and XerD perform a similar function for the E. coli chromosome as well as for multicopy plasmids.585 586 The XerC / XerD system is... 

Other research groups are combining stress inducible promoters with the Cre-LoxP site specific recombination system of PI bacteriophage. Scott et al. (2000) have combined the ionizing radiation inducible EGR-1 promoter with this recombination system to express herpes simplex vims thymidine kinase (HSV-tk). With this combination system, radiation doses relevant for cancer treatment can be used to... 

Kndoh, H., Ikeda, H., Kakitani, M., Ueda, A., Hayasaka, M., Tomizuka, K., et al. (2005) A new model mouse for Duchenne muscular dystrophy produced by 2.4 Mb deletion of dystrophin gene using Cre-loxP recombination system. Biochem Biophys Res Commun 328, 507-516. 

Iwatate, M., Gu, Y., Dieterle, T. et al. (2003). In vivo high-efficiency transcoronary gene delivery and Cre-LoxP gene switching in the adult mouse heart. Gene Ther. 10(21), 1814-1820. 

Kuhn, R. and R. Torres (2002) Cre/loxP recombination and gene targeting. Methods in Molecular Biology 180,175-204. 

A disadvantage of these systems is probably the lower efficiency and convenience of cloning libraries of DNA molecules. This difficulty has been alleviated by using a Cre-loxP recombination strategy the fusion gene is cloned in a small plasmid and then efficiently recombined in vivo into the phage [25],... 

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