C57BL/6-Cfl2^tm1Itl/J

Stock number: 018135
Research areas: Neurobiology Research, Research Tools

Description

These Cofi/Cofi mice possess loxP sites flanking exons 2-4 of the Cfl2 gene. They may be useful in applications studying the maintenance. and development of skeletal and cardiac muscles.

Detailed description

These Cofi/Cofi floxed mutant mice possess loxP sites flanking exons 2-4 of the cofilin 2 (Cfl2) gene. They also contain a frt-flanked neo cassette followed by a single loxP site downstream of exon 4. Cofilin is a member of the AC group of proteins expressed at sarcomeres in skeletal and cardiac muscles. Cofilin regulates muscle development and actin dynamics by severing actin filaments and causing actin depolymerization. Cfl2 mutations have been associated with the neuromuscular disorder 'nemaline myopathy with minicores', which is characterized by weakness and the presence of rodlike structures called nemaline bodies in affected muscles. Mice that are homozygous for this allele are viable and fertile. When these mice are bred to mice that express Cre recombinase, resulting offspring will have exons 2-4 deleted in cre-expressing tissues.

For example, when crossed to B6.Cg-Tg(ACTA1-cre)79Jme/J mice (see Stock No. 006149) expressing Cre recombinase in striated muscle, or to B6.FVB(129S4)-Tg(Ckmm-cre)5Khn/J mice (see Stock No. 006475) expressing Cre recombinase in postnatal skeletal and cardiac muscle, Cfl2-deficient mice dice by postnatal day 8. These mice are smaller than their littermates, exhibit severe skeletal muscle degeneration, and have empty stomachs due to inability to suckle.

Development

A targeting vector was designed to insert a single loxP site upstream of exon 4 and a frt-flanked/floxed neomycin resistance (neo) cassette downstream of exon 4 of the cofilin 2 (Cfl2) gene. The construct was electroporated into C57BL/6NTac-derived IC1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into BALB/c blastocysts and resulting chimeric mice were bred with C57BL/6 mice. Homozygous males with black coat color were sent to The Jackson Laboratory Repository in 2012. Upon arrival, males were used to cryopreserve sperm. To establish the living mouse colony, an aliquot of the frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the first generation rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 4 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data confirm that the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J;C57BL/6N genetic background.

Allele

Symbol: Cfl2^tm1Itl
Name: targeted mutation 1, inGenious Targeting Laboratory
MGI accession ID: MGI:5316051
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Cfl2
Marker name: cofilin 2, muscle
Chromosome: 12
Strain of origin: C57BL/6NTac
Molecular note: A targeting vector was designed to insert a single loxP site upstream of exon 4 and a frt-flanked/floxed neomycin resistance (neo) cassette downstream of exon 4.