STOCK En2^tm6Alj/J

Stock number: 008872
Research areas: Neurobiology Research, Research Tools

Description

These En2^lox 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.

Detailed description

Mice homozygous for the En2^lox 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 En2^lox 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.

Development

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.

Allele

Symbol: En2^tm6Alj
Name: targeted mutation 6, Alexandra L Joyner
MGI accession ID: MGI:3831084
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: En2
Marker name: engrailed 2
Chromosome: 5
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.