Mc4rflox mice possess loxP sites flanking the entire coding region of the melanocortin 4 receptor (Mc4r) gene. These mice may be useful when studying neurobiology, obesity, diabetes, hunger/appetite, and fat and energy metabolism.
Bradford B. Lowell, Beth Israel Deaconess Med Cntr (Harvard)
Mc4rflox mice possess loxP sites flanking the entire coding region of the melanocortin 4 receptor (Mc4r) gene. MC4R is a member of the rhodopsin family of 7-transmembrane G protein-coupled receptors and is involved in energy homeostasis, somatic growth, pigmentation and inflammation. Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have then entire coding region of Mc4r deleted in cre-expressing tissues.
The Mc4rflox targeting vector was designed to insert a loxP-site in the 5’ UTR, and a second loxP site followed by a frt-flanked kanamycin resistance cassette downstream of the 3’UTR of the melanocortin 4 receptor (Mc4r) gene. The construct was electroporated into 129S6/SvEvTac-derived W4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and resulting chimeric males were bred with 129S4/SvJaeSor-Gt(ROSA)26Sortm1(FLP1)Dym/J (Stock No. 003946) females to delete the kanamycin cassette. Resulting Mc4rflox mice were crossed to remove the Flp-expressing allele, and were subsequently bred to C57BL/6 mice. Mice were maintained on a mixed genetic background. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
|Allele Name||targeted mutation 2.2, Bradford B Lowell|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Mc4r, melanocortin 4 receptor|
|Strain of Origin||129S6/SvEvTac|
|Molecular Note||One loxP site was inserted in the 5'UTR and a second loxP site followed by a FRT-flanked kanamycin resistance cassette was inserted in the 3'UTR. The single coding exon is thus flanked by loxP sites. Flp-mediated recombination removed the FRT-flanked kanamycin cassette.|
When maintaining a live colony, mice homozygous for the floxed allele may be bred together.
When using the Mc4rflox mouse strain in a publication, please cite the originating article(s) and include JAX stock #023720 in your Materials and Methods section.