B6.129(FVB)-Igf1^tm1Dlr/J

Stock number: 016831
Product name: Igf1^flox
Research areas: Research Tools

Description

Removal of this mouse colony is imminent. If live mice are needed for your studies, it is advised that they be ordered immediately. After removal, the mice will be available from a cryorecovery.

These floxed mutant mice possess loxP sites flanking exon 4 of the Igf1 gene and a neomycin resistance (neo) cassette. This strain may be useful for studying postnatal growth and development.

Detailed description

These mutant mice feature loxP sites flanking exon 4 of the insulin-like growth factor 1 (Igf1) gene and a neomycin resistance cassette. Homozygotes for this allele are viable, fertile, and normal in size. IGF1 promotes cell survival and cell proliferation by activating the tyrosine kinase transmembrane receptor, IGF-1R. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exon 4 deleted in cre-expressing tissues. For example, when these mice are bred to Tg(Alb1-cre)1Dlr/J mice (Stock No. 016832 or Stock No. 016833), IGF1 expression is abolished in liver. This strain may be useful for studying postnatal growth and development.

When bred to a strain expressing Cre recombinase in the early mouse embryo (see Stock No. 003724 for example), this mutant mouse strain may be useful in studies of early development.

Development

A targeting vector was designed to insert a loxP site upstream of exon 4 and a neomycin resistance (neo) cassette and second loxP site downstream of exon 4 of the insulin-like growth factor 1 (Igf1) gene. The construct was electroporated into 129-derived embryonic stem (ES) cells, and correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric males were bred with C57BL/6J females, and their offspring were subsequently crossed to FVB-Tg(Alb1-cre)1Dlr mice. The donating investigator reported that these mice were backcrossed to C57BL/6J inbred mice for at least 9 generations (see SNP note below). Upon arrival, the mice were bred to C57BL/6J inbred mice (Stock No. 000664) for one generation and transgene was selectively bred out of the line.

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, all 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a C57BL/6N genetic background.

Allele

Symbol: Igf1^tm1Dlr
Name: targeted mutation 1, Derek LeRoith
MGI accession ID: MGI:2152423
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Synonyms: IGF-I loxP; LI-IGF-I-; LID; IGF-I^flox; Igf1^floxed
Marker symbol: Igf1
Marker name: insulin-like growth factor 1
Chromosome: 10
Strain of origin: 129
Molecular note: A neomycin cassette and loxP sites were inserted flanking exon 4. The introduction of these mutations had no effect on the normal function of the gene.
General note: ES cells = 129/Sv