B6.Cg-Lamc2^tm1Uit/DcrJ

Stock number: 025335
Research areas: Dermatology Research, Developmental Biology Research, Endocrine Deficiency Research, Internal/Organ Research

Description

This Lamc2 knock out strain may be useful in studies of epidermolysis bullosa and is a model for Herlitz Type Junctional Epidermolysis Bullosa.

Detailed description

The Lamc2 gene encodes for the gamma-2 subunit of laminin 332 (laminin 5), which is an extracellular matrix glycoprotein found in cutaneous basement membranes. These mice carry a knock out mutation of Lamc2 which results in a frameshift deletion of exon 8. Mice that are homozygous for the targeted mutation die by 5 days of age. Heterozgyotes are viable and fertile. No protein gene product is detected by immunofluorescence screening of skin from homozygotes. A truncated 291bp transcript is detected by RT-PCR analysis of skin from homozygotes and heterozygotes. Onset of the progressive blistering phenotype occurs within 1 to 2 days of birth in almost all homozygous mice. Dermal-epidermal tissue separation is found in the skin and mucous membranes (oral mucosa, urinary bladder).

Development

A loxP site flanked targeting vector designed containing a NEO-TK cassette was utilized in the construction of this mutant. This selection cassette and a FRT site was inserted downstream of exon 8 of the targeted gene, and another loxP site was inserted upstream of exon 8. A second FRT site was inserted downstream of exon 9. The construct was electroporated into unspecified embryonic stem (ES) cells which were transiently transfected with a Cre recombinase vector to remove the selection cassette. ES cells that had successfully undergone Cre-mediated recombination and no longer retained the cassette or exon 8 were injected into C57BL/6J blastocysts. The resulting chimeric animals were crossed to C57BL/6J mice. The mice were then backcrossed to C57BL/6J for 13 generations. Upon arrival at The Jackson Laboratory Repository, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.

Allele

Symbol: Lamc2^tm1Uit
Name: targeted mutation 1, Jouni Uitto
MGI accession ID: MGI:2679597
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Lamc2
Marker name: laminin, gamma 2
Chromosome: 1
Strain of origin: Not Specified
Molecular note: A floxed neomycin resistance gene was inserted in intron 8 and another loxP site was placed in intron 7. Also, frt sites were inserted on either side of exon 9. Transient cre expression in the ES cells removed exon 8 which caused a frame shift and a premature termination codon in exon 9. RT-PCR indicated mRNA of 510bp rather than 623bp. There was also a minor smaller transcript of 291bp. No protein product could be seen immunologically in skin biopsies of homozygous mice.