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pSC101-BAD-Cre

Arabinose inducible prokaryotic Cre recombinase expression plasmid.

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Description

Site-specific recombinases (SSRs) like Cre or Dre are valuable tools in functional genomics and have been applied in various organisms. They mediate recombination between target sites of 32-34 base pairs (bp) in length. The target sites, which are called loxP or rox sites are 13-14 bp palindromes separated by spacers:

loxP	5-ATAACTTCGTATAATGTATGCTATACGAAGTTAT-3
rox	5-TAACTTTAAATAATGCCAATTATTTAAAGTTA-3

Recognition sites of the site-specific recombinases Cre (loxP) and Dre (rox).

Cre recombinase, which was originally isolated from coliphage P1, mediates recombination between two loxP-sites through the spacer regions (e.g. removal of selectable genes). Dre was identified in a systematic search through P1-like phages for a Cre-like enzyme that had diverged sufficiently to recognize a recombination target site (RT) that is distinct from loxP (Sauer and Mc Dermott, 2004).

The combination of the arabinose inducible BAD promoter and the low-copy pSC101 plasmid backbone provide an excellent on-off regulation of Cre or Dre in E. coli as proved in a test experiment (Anastassiadis et al. 2009).

The plasmids carry a tetracyclin resistance gene for selection and are compatible with plasmids based on a ColE1 or p15A origin of replication and an ampicillin or kanamycin resistance marker.

While Cre/loxP is widely used in mouse genetics for conditional mutagenesis with many mouse lines available, a second highly efficient system like Dre/rox opens the door for more complex tasks such as a conditional mutagenesis of alternatively spliced exons. Cre/loxP can be used to remove one alternative exon and Dre/rox to remove the other one.

Map of pSC101-BAD-Cre