These En2lox mice have loxP sites flanking the engrailed homeodomain portion in exon 2 of the engrailed 2 gene. These mice may be used to generate conditional mutations for studying engrailed protein function in the developing mesencephalon, rhombomere 1, and jaw muscles, as well as the embryonic and adult cerebellum.
Dr. Alexandra L Joyner, Memorial Sloan-Kettering Cancer Center
Mice homozygous for the En2lox conditional allele are viable and fertile, with loxP sites flanking the coding region of exon 2 of the targeted gene. When bred to mice that express Cre recombinase, the resulting offspring will have the floxed region (encoding the engrailed homeodomain) deleted in the cre-expressing tissues. These En2lox mice may be useful in generating conditional mutations for studying engrailed protein function in the developing mesencephalon, rhombomere 1, and jaw muscles, as well as the embryonic and adult cerebellum.
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 En2neo-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 En2lox offspring. En2lox 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 En2lox colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J female mice (Stock No. 000664). The En2lox colony was then maintained by breeding heterozygous or homozygous mice together, to wildtype mice from the colony or to C57BL/6J inbred mice.
|Allele Name||targeted mutation 6, Alexandra L Joyner|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Allele Synonym(s)||En2flox; En2lox|
|Gene Symbol and Name||En2, engrailed 2|
|Strain of Origin||129S6/SvEvTac|
|Molecular Note||The targeting construct contains a 3.1 kb En2 5' fragment, an Frt-flanked PGK-neo cassette followed by a LoxP site in the En2 intron and a 4.8 kb En2 genomic fragment containing a LoxP site in the XbaI site of the 3' UTR. Flpe-mediated recombination deleted the PGK-neo, producing an En2 allele with a floxed region.|
|Mutations Made By|| |
Dr. Alexandra Joyner, Memorial Sloan-Kettering Cancer Center
When maintaining a live colony, heterozygous mice may be bred to wildtype mice from the colony or with C57BL/6J inbred mice (Stock No. 000664). As the donating investigator reports that homozygous mice are viable and fertile, the colony may also be maintained by breeding homozygous mice together.
When using the STOCK En2tm6Alj/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #008872 in your Materials and Methods section.