B6;129X1-Itgb1^tm1Mll/AjkJ

Stock number: 029354
Product name: beta1-flox
Research areas: Neurobiology Research, Research Tools

Description

These beta1-flox mutant mice possess loxP sites flanking exon 1 of the Itgb1 gene. This strain may be useful for generating conditional mutations in applications related to cell adhesion, cell migration, embryonic development, as well as the inflammatory immune response.

Detailed description

The targeted Itgb1 gene encodes the the integrin beta 1 subunit (also known as fibronectin receptor beta) and is the most abundant beta-integrin. These mice possess loxP sites on either side of exon 1 of the targeted gene. 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 the cre-expressing tissues. When crossed to nestin-cre mice (in which Cre recombinase activity is detected at E10.5 in neural tissue), no protein detected in neural tissue from embryos aged embryonic days 12.5 and 15.5, and postnatal day 1 neonates.

When bred to a strain with Cre recombinase expression in embryonic neural tissue (see Stock No. 003771 for example), this mutant mouse strain may be useful in studies of neuronal structure and development.

Development

Dr. Ulrich Muller, while at Friedrich Miescher Institute (Basel, Switzerland), designed a targeting vector containing a loxP site flanked neo-IRES-tk cassette in the construction of this mutant. This selection cassette was inserted downstream of exon 1 of the targeted gene, and another loxP site was inserted upstream of exon 1. The construct was electroporated into 129X1/SvJ derived JM-1 embryonic stem (ES) cells which were transiently transfected with a Cre recombinase plasmid to remove the selection cassette. ES cells in which Cre recombination resulted in exon 1 being flanked by loxP sites were injected into C57BL/6 blastocysts. The resulting male chimeric animals were crossed to female C57BL/6 mice. 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

Symbol: Itgb1^tm1Mll
Name: targeted mutation 1, Ulrich Muller
MGI accession ID: MGI:2156945
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Itgb1
Marker name: integrin beta 1 (fibronectin receptor beta)
Chromosome: 8
Strain of origin: 129X1/SvJ
Molecular note: LoxP sites were inserted flanking the first coding exon as follows: One loxP site was inserted 5' to the exon and a loxP-flanked neomycin and thymidine kinase selection cassette was inserted 3' to the exon. The neomycin and thymidine kinase selection cassette was removed via Cre-mediated recombination in ES cells prior to creation of chimeric mice, leaving one loxP site in place of the cassette.