STOCK Myl1^{tm1.1(cre/ERT2)Lepr}/J

Stock number: 025670
Product name: Myl1^CE
Research areas: Cell Biology Research, Research Tools

Description

These mice express tamoxifen-inducible Cre recombinase under the direction of the Myl1 promoter in fast skeletal muscle.

Detailed description

Myl1^CE mice express a Cre-ERT2 fusion protein from endogenous Myl1 promoter/enhancer elements. MYL1 is an ATPase cellular motor protein involved in the development of fast skeletal muscle. Heterozygous mice are viable and fertile. When Myl1^CE mice are bred with mice containing loxP-flanked sequence, tamoxifen-inducible, Cre-mediated recombination will result in deletion of the floxed sequences.

For example, when bred to B6.129S4-Gt(ROSA)26Sor^tm1Sor/J mice (Stock No. 003474), tamoxifen-inducible cre-mediated recombination results in lacZ staining of several muscle groups from E14.75 and E15.75, and in tibialis anterior (TA) muscles from E15.75 to E17.25. E12.75 to E16.5 staining is detected in very few loosely clustered myofibers. lacZ staining was very weak in the limb muscles of adult animals, and was absent from the heart.

 

Development

A targeting vector was designed to replace exon 1e of the myosin, light polypeptide 1 (Myl1) gene with a CreERT2 (Cre recombinase fused to an estrogen receptor ligand binding domain) coding sequence and a frt-flanked neomycin (neo) resistance cassette. This construct was electroporated into C57BL/6;129sv embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts. The resulting chimeric animals were crossed to Tg(ACTFLPe)9205Dym/J mice expressing FLP recombinase to remove the neo selection cassette. Offspring were then crossed to remove the Flp-expressing transgene. These mice were bred to 129svJ mice for at least 3 generations. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Myl1^{tm1.1(cre/ERT2)Lepr}
Name: targeted mutation 1.1, Christoph Lepper
MGI accession ID: MGI:5620012
Generation method: Targeted
Attributes: Recombinase-expressing; Inducible; Null/Knockout
Marker symbol: Myl1
Marker name: myosin, light polypeptide 1
Chromosome: 1
Strain of origin: C57BL/6 x 129
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: Cre-ERT2 fusion protein is expressed from endogenous Myl1 promoter/enhancer elements during the development of fast skeletal muscle.
Molecular note: A rabbit beta-globin intron, cre/ERT2 fusion gene, SV40 late polyadenylation signal and FRT-flanked neomycin cassette replaced the coding sequence in exon 1. Flp-mediated recombination removed the selection cassette.