Use of mutated FLP recognition target (FRT) sites for the exchange of expression cassettes at defined chromosomal loci

Biochemistry. 1994 Nov 1;33(43):12746-51. doi: 10.1021/bi00209a003.


Using the FLP/FRT system for site-specific recombination and the wild-type recognition site (FRT) in conjunction with certain mutant FRT sites, it becomes possible to provoke, with high yield, a double-reciprocal crossover event in cultured mammalian cells. It is demonstrated that this technology enables a targeting of expression cassettes to appropriate chromosomal reference sites in the recipient cell to improve the concepts of reverse genetics. The design of mutant FRT sites promoting such a process will be delineated. Our results show that the five spacer mutations tested are functional as the wild type but differ in the extent of their cross-recombination, which has to be minimized for their simultaneous usage.

MeSH terms

  • Animals
  • Base Sequence
  • Binding Sites
  • Cell Line
  • Cricetinae
  • DNA / chemistry*
  • DNA / genetics
  • DNA / metabolism
  • DNA Nucleotidyltransferases / metabolism*
  • Kidney
  • Molecular Sequence Data
  • Mutagenesis
  • Mutation*
  • Polymerase Chain Reaction
  • Recombination, Genetic
  • Repetitive Sequences, Nucleic Acid
  • Transfection
  • Transferases
  • beta-Galactosidase / genetics


  • DNA
  • Transferases
  • DNA Nucleotidyltransferases
  • FLP recombinase
  • beta-Galactosidase