FVB.129(Cg)-Igs2^tm1Kng/J

Stock number: 031321
Product name: ANC-Kitl
Research areas: Dermatology Research

Description

ANC-Kitl mice carry a knock-in mutation which expresses ectopic mouse Kitl in developing hair follicles and skin under the control of the ancestral (ANC) form of the human KITL (KITLG) locus enhancer.

Detailed description

A regulatory region upstream of the Kitl (kit ligand; KITLG) gene controls hair pigmentation in both humans and mice and is associated with common blond hair color in northern Europeans.

These ANC-Kitl mice carry a knock-in mutation which expresses ectopic mouse Kitl in developing hair follicles and skin under the control of an 864 bp hair enhancer (HE) isolated from the human KITL (KITLG) locus. The blond (BLD) form (CGCTAAAG) of the hair enhancer differs from the derived ancestral (ANC) form (CACTAAAG) by only a single base pair that falls within a putative lymphoid enhancer-binding factor/T-cell factor (LEF/TCF) binding site.

These animals are healthy and fertile. Carriers of the mutation have no apparent phenotype on the FVB background. When crossed to C57BL/6J however, heterozygous ANC-Kitl animals have slightly darker fur than their wild type littermates and BLD-Kitl heterozygotes (see Stock No. 031326) also on the C57BL/6J background. In addition, they have ectopic pigmentation on the muzzle, the epithelium of the antitragus and the ear canal. Cross sections through the skin show pigmentation in the follicular bulge and sporadically in the basal epidermis. They show reduced pigmentation of the whiskers and digits.

Development

A targeting construct (attB-Hsp68 minimal promoter-ANC-Kitl-SV40-attB-FRT5) and φC31 mRNA were co-injected into a single pronucleus of FVB-H11P3 zygotes to produce these ANC-Kitl mice.

The FVB-H11P3 strain used for embryo injections was created by introducing three tandem attP sites (P3) to the Hipp11 (H11; Igs2 intergenic site 2) region on mouse Chromosome 11 via homologous recombination in 129-derived embryonic stem (ES) cells. Resultant chimeric male mice were bred to B6D2F1/J females prior to four generations of backcrossing to FVB/NCrl.

ANC represents the ancestral form of a human 864 bp hair enhancer (HE) isolated from the human KITL (KITLG) locus. Co-injected φC31 catalyzed the integration of a single copy of ANC-Kitl into the Igs2 (H11) site via a recombinase-mediated cassette exchange reaction. Resultant mice were bred to inbred FVB/NCrl mice for at least 2 generations by the donating laboratory.

Allele

Symbol: Igs2^tm1Kng
Name: targeted mutation 1, David M Kingsley
MGI accession ID: MGI:6095646
Generation method: Targeted
Attributes: Reporter
Synonyms: ANC-Kitlg
Marker symbol: Igs2
Marker name: intergenic site 2
Marker synonyms: H11; Hipp11; Iis2
Chromosome: 11
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: Kitl,kit ligand,mouse, laboratory
Site of expression: Developing hair follicles and skin.
Molecular note: The targeting construct contains an attB site, mouse Hsp68 minimal promoter, a human regulatory region (H2), mouse Kitl cDNA, SV40, an attB site and FRT5. The construct and phiC31 mRNA were co-injected into a single pronucleus of FVB-H11P3 zygotes. H2 is regulatory enhancer located in an intergenic region 350 kb upstream of the Kitl transcription start site, it contains a non-coding SNP (rs12821256) associated with hair color. The ancestral (ANC) polymorphism (A) is associated with brown hair, and the BLD polymorphism (G) is associated with blond hair. This allele carries the A polymorphism.
General note: ES cell line = FVB-H11P3, a 129-derived embryonic stem cell line (R1) carrying three tandem attP sites (P3) at Hipp11.