STOCK Ip6k1^tm1.1Snyd/J

Stock number: 029843
Product name: Ip6k1 knockout
Research areas: Developmental Biology Research, Diabetes and Obesity Research, Hematological Research, Internal/Organ Research, Reproductive Biology Research

Description

This Ip6k1 knockout strain is resistant to diet induced obesity, exhibits reduced body size due to decreased adiposity, defective platelet function, and is useful in studies of type 2 diabetes mellitus, energy metabolism, and obesity.

Detailed description

The targeted Ip6k1 gene encodes an inositol hexaphosphate kinase. Mutations in this gene have been associated with type 2 diabetes mellitus. These mice carry a knock-out targeted mutation of the Ip6k1 gene, in which exon 6 has been excised. Exon 6 encodes amino acids 265 to 433, the C-terminal catalytic domain of the kinase. No gene product (mRNA or protein) is detected by RT-PCR analysis of brain and liver tissue, and western blot analysis of platelets from homozygotes. Homozygous male mice are infertile due to arrested spermiogenesis and azoospermia. Homozygous female mice are viable and fertile. Homozygotes exhibit smaller body size, decreased plasma insulin levels (65–70% reduction), decreased serum leptin levels and reduced platelet polyphosphate levels, when compared to wildtype controls. Platelet function is altered in homozygotes with reduced aggregation following thrombin stimulation, longer clotting time and abnormal clot ultrastructure. As a result, homozygous mice exhibit longer bleeding time. Reduced body size and weight in homozygotes is due to decreased fat accumulation (epididymal adipose tissue, visceral and subcutaneous adipose tissue), although brown fat is unchanged and gastrocnemius muscle mass is increased. When fed a high fat diet, mutant mice are resistant to diet induced obesity: the rate of weight gain in homozygotes is much lower than that observed in wildtype controls.

Development

A targeting vector containing a FRT site flanked PGKneo cassette with a 5' loxP site was used to disrupt exon 6. Another loxP site was inserted upstream of exon 6 (295 bp upstream of the exon 6 splice site). The construct was electroporated into unspecified embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were tested for germline transmission. The mice were crossed to knock-in mice expressing Cre recombinase under the control of a PGK promoter, on the C57BL/6 genetic background, to excise the floxed coding sequence of exon 6. Heterozygotes were intercrossed to generate homozygotes. Upon arrival, sperm from heterozygous males was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

Allele

Symbol: Ip6k1^tm1.1Snyd
Name: targeted mutation 1.1, Solomon Snyder
MGI accession ID: MGI:3775918
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: IP6K1^-
Marker symbol: Ip6k1
Marker name: inositol hexaphosphate kinase 1
Marker synonyms: 1200016D08Rik; Ihpk1; InsP6; InsP6k1; Itpk6; PiUS
Chromosome: 9
Strain of origin: 129X1/SvJ
Molecular note: The first part of exon 6 that contains the C-terminal coding region was removed by germ-line, cre-mediated recombination. The absence of transcript was confirmed by RT-PCR analysis on brain and liver extracts.