Site-specific DNA recombination in mammalian cells by the Cre recombinase of bacteriophage P1

Proc Natl Acad Sci U S A. 1988 Jul;85(14):5166-70. doi: 10.1073/pnas.85.14.5166.


The Cre protein encoded by the coliphage P1 is a 38-kDa protein that efficiently promotes both intra- and intermolecular synapsis and recombination of DNA both in Escherichia coli and in vitro. Recombination occurs at a specific site, called lox, and does not require any other protein factors. The Cre protein is shown here also to be able to cause synapsis of DNA and site-specific recombination in a mammalian cell line. A stable mouse cell line was established that expresses the Cre protein under the control of the Cd2+-inducible metallothionein I gene promoter. DNA recombination was monitored with DNA substrates containing two directly repeated lox sites. One such substrate is a circular plasmid with two directly repeated lox sites (lox2) flanking a marker gene and was introduced into cells by Ca3(PO4)2 transformation. As a second substrate we used a pseudorabies virus (a herpesvirus) containing a lox2 insertion designed to provide a sensitive detection system for recombination. In both cases, site-specific recombination in vivo is dependent on the presence of the Cre protein and occurs specifically at the 34-base-pair lox sites. These results demonstrate the controlled site-specific synapsis of DNA and recombination by a prokaryotic protein in mammalian cells and suggest that Cre-mediated site-specific recombination may be a useful tool for understanding and modulating genome rearrangements in eukaryotes.

MeSH terms

  • Animals
  • Bacteriophages / enzymology*
  • Bovine papillomavirus 1 / genetics
  • Cell Line
  • DNA / genetics*
  • DNA Nucleotidyltransferases / genetics
  • DNA Nucleotidyltransferases / metabolism*
  • DNA Restriction Enzymes
  • DNA Transposable Elements
  • DNA, Recombinant
  • Electrophoresis, Polyacrylamide Gel
  • Herpesvirus 1, Suid / genetics
  • Immunoassay
  • Integrases*
  • Mice
  • Nucleic Acid Hybridization
  • Plasmids
  • Promoter Regions, Genetic
  • Recombination, Genetic*
  • Transformation, Genetic
  • Viral Proteins*


  • DNA Transposable Elements
  • DNA, Recombinant
  • Viral Proteins
  • DNA
  • Cre recombinase
  • DNA Nucleotidyltransferases
  • Integrases
  • DNA Restriction Enzymes