A targeting construct was designed to insert an frt-flanked neomycin cassette and loxP site within intron 1, and a loxP site downstream of the coding region in the second exon of the targeted gene. This construct was electroporated into 129S6/SvEvTac-derived W4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts and chimeric mice were bred with Black Swiss outbred mice. The resulting En2^neo-lox mice were then bred to C57BL/6-congenic mice constitutively expressing Flp recombinase (hACTB-Flpe deleter mice; see Stock No. 005703) to remove the frt-flanked neo cassette; thus generating En2^lox offspring. En2^lox mutant mice were bred together or to Swiss Webster mice for many generations (and the Flp transgene was removed) prior to sending to The Jackson Laboratory Repository in 2013. In addition, the donating investigator reports that although these mice harbor no additional mutant loci, they may contain incidental genetic background contributions as a result of past matings with engrailed-1 mutant lines and/or Cre recombinase-expressing lines. Upon arrival, sperm was cryopreserved. To generate the living En2^lox colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J female mice (Stock No. 000664). The En2^lox colony was then maintained by breeding heterozygous or homozygous mice together, to wildtype mice from the colony or to C57BL/6J inbred mice.

• Wild-type from the colony

Additional Information

• Considerations for Choosing Controls

• Cheng Y; Sudarov A; Szulc KU; Sgaier SK; Stephen D; Turnbull DH; Joyner AL. 2010. The Engrailed homeobox genes determine the different foliation patterns in the vermis and hemispheres of the mammalian cerebellum. Development 137(3):519-29PubMed: 20081196MGI: J:156169