High-efficiency CAG-FLPe deleter mice in C57BL/6J background

Exp Anim. 2006 Apr;55(2):137-41. doi: 10.1538/expanim.55.137.


The increasing popularity of conditional knockout (KO) technology has resulted in the demand for efficient FLP deleter mice. In addition, FLP deleters are needed in genetic backgrounds that are suited to behavioral studies. We generated CAG-FLPe transgenic (Tg) mice with the C57BL/6J genetic background, which is one of the most commonly-used strains in behavioral studies. We assessed the recombination efficiency of the CAG-FLPe-Tg lines by crossing them with a mouse line carrying a FRT-PGK-neo-FRT cassette. Four of five independent CAG-FLPe lines induced recombination in most (91%-100%) of their progenies, although a small fraction (0%-30%, depending on the line) showed mosaic recombination patterns. These animals are highly potent as deleters of FRT cassettes and are useful for behavioral studies involving conditional KO mice.

MeSH terms

  • Animals
  • DNA Nucleotidyltransferases / genetics*
  • Female
  • Genetic Techniques
  • Male
  • Mice
  • Mice, Inbred C57BL*
  • Mice, Knockout
  • Mice, Transgenic*
  • Recombination, Genetic


  • DNA Nucleotidyltransferases
  • FLP recombinase