STOCK Blm^tm4Ches/J

Stock number: 008670
Research areas: Research Tools

Description

These Blm, Bloom syndrome homolog (human), mutant mice possess loxP sites on either side of exon 8 and may be useful in generating conditional mutations for studying Bloom Syndrome.

Detailed description

These mice possess loxP sites on either side of exon 8 of the targeted gene. Mice that are homozygous for this allele are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exon 8 deleted in the cre-expressing tissue(s).

When bred to a strain with Cre recombinase expression in mammary cells, or a strain with widespread Cre recombinase expression, this mutant mouse strain may be useful in studies of Bloom Syndrome.

Development

A loxP site flanked targeting vector containing neomycin resistance and thymidine kinase genes was utilized in the construction of this mutant. This selection cassette was inserted downstream of exon 8 of the targeted gene, and another loxP site was inserted upstream of exon 8. This construct was electroporated into 129S6/SvEvTac derived TC-1 embryonic stem (ES) cells which were transiently transfected with a Cre recombinase plasmid to remove the selection cassette. ES cells that had successfully undergone Cre recombination and no longer retained the cassette but did retain the loxP-flanked exon 8 were injected in recipient blastocysts. Resulting chimeric male animals were backcrossed to NIH Black Swiss outbred mice. Upon arrival at The Jackson Laboratory the mice were crossed with C57BL/6J once to establish the colony.

Allele

Symbol: Blm^tm4Ches
Name: targeted mutation 4, Nicholas Chester
MGI accession ID: MGI:3663359
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Blm
Marker name: Bloom syndrome, RecQ like helicase
Chromosome: 7
Strain of origin: 129S6/SvEvTac
Molecular note: A floxed PGK-neomycin resistance gene was inserted into intron 8 and an additional loxP site was placed in intron 7, 75 bp from the start of exon 8. Transient cre expression removed the PGK-neo sequence from correctly targeted ES cells, leaving loxP sites flanking exon 8.