Mc1Rfl/fl floxed mice possess loxP sites flanking exon 1 of the melanocortin 1 receptor (Mc1r) gene. This strain may be useful for studying pigmentation, melanocyte regeneration, and the development of melanomas.
Mayumi Ito, New York University School of Medicine
Mc1Rfl/fl floxed mice possess loxP sites flanking exon 1 of the melanocortin 1 receptor (Mc1r) gene. MC1R is a G protein coupled receptor for melanocyte-stimulating hormone (MSH). The binding of MSH to MC1R activates the receptor and stimulates the synthesis of photoprotective black eumelanin melanin and UV-sensitive red pheomelanin melanin. MC1R loss results in defects in regeneration of epidermal melanocytes. 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 exon 1 deleted in cre-expressing tissues. After cre recombination in melanocyte lineage, KO mice showed yellow hair color and reduced number of epidermal melanocytes after wounding.
A targeting vector was designed to insert a single loxP site upstream of exon 1, and a loxP-flanked and frt-flanked neomycin resistance (neo) cassette downstream of exon 1, of the melanocortin 1 receptor (Mc1r) gene. The construct was electroporated into (C57BL/6N x 129S6/SvEvTac)F1-derived iTL BA1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and resulting chimeric males were bred with FLP deleter mice to remove the neo cassette. Resulting offspring were bred to establish a colony of Mc1Rfl/fl mice on a mixed 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 1.1, Mayumi Ito|
|Allele Type||Targeted (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Mc1r, melanocortin 1 receptor|
|Strain of Origin||(C57BL/6NTac x 129S6/SvEvTac)F1|
|Molecular Note||The targeting vector is designed to insert a single loxP site upstream of exon 1, and a loxP-flanked and FRT-flanked neomycin resistance (neo) cassette downstream of exon 1. Flp-mediated recombination removed the FRT-flanked neo cassette.|
When maintaining a live colony mice homozygous for the floxed allele may be bred together.
When using the Mc1Rfl mouse strain in a publication, please cite the originating article(s) and include JAX stock #029239 in your Materials and Methods section.