B6.Cg-Tg(CAG-OTC/CAT)4033Prab/J

Stock number: 016197
Product name: mCAT
Research areas: Cardiovascular Research, Diabetes and Obesity Research, Metabolism Research, Neurobiology Research, Research Tools, Sensorineural Research

Description

C57BL/6.mCAT mice (MCAT transgenic mice) have a CMV enhancer/chicken beta-actin promoter driving the expression of human Catalase gene in mitochondria. These mice may be useful for studying the role of reactive oxygen species in mammalian longevity, as well as protection from lung adenocarcinoma.

Detailed description

C57BL/6.mCAT mice (MCAT transgenic mice) have a CMV enhancer/chicken beta-actin promoter (CAG; from the pCAGGS vector) driving the expression of a human Catalase (CAT) gene in mitochondria. Hemizygous MCAT mice are viable and fertile. Catalase is an enzyme, normally expressed in peroxisomes, that reduces hydrogen peroxide (H₂O₂) to water and molecular oxygen, mitigating the potential for H₂O₂ to cause damage to molecules. Mitochondrial catalase expression in MCAT mice results in a 5.5-month increase in median life span for both males and females. Catalase activity is elevated in heart, skeletal muscle, and brain. Cardiac mitochondria have 50 times higher catalase activity than in wild-type littermates leading to a delay in cardiac pathology. They also display improved cardiac performance with age, reducing their susceptibility to cardiac hypertrophy and failure. The severity of cataracts is reduced at 17 months of age, but rebounds to the level found in wildtype mice by 30 months of age. These MCAT mice also exhibit enhanced exercise performance, reduced age-dependent hearing loss, and reserved insulin sensitivity when fed a high-fat diet. When treated with the antiviral drug azidothymidine (AZT) they have a reduction in cardiomyopathy, and they show a reduction in MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced Parkinson's disease. H₂O₂ production and H₂O₂-induced aconitase inactivation are attenuated, and the development of mitochondrial deletions is reduced. These mice may be useful for studying the role of reactive oxygen species in mammalian longevity, as well as protection from lung adenocarcinoma.

Development

The MCAT transgene was designed with the human Catalase (CAT) gene driven by a CMV enhancer/chicken beta-actin promoter (CAG; from the pCAGGS vector). The initiating methionine of CAT was deleted, and the first 25 amino acids of the ornithine transcarbamylase (Otc) leader sequence were added to the amino terminus to target this protein product to mitochondria. The transgene was microinjected into fertilized B6(B6C3F1) oocytes, and mice from founder line 4033 were bred to C57BL/6J mice. These mice were crossed to C57BL/6J mice for at least eight generations to establish a colony. In C57BL/6J mice, a naturally occurring deletion of exons 7-11 of the nicotinamide nucleotide transhydrogenase (Nnt) makes this strain more sensitive to oxidative challenge. For that reason, these mice have been crossed to C57BL/6NCrl mice to maintain an intact Nnt allele. Upon arrival at The Jackson Laboratory, transgenic mice were bred to C57BL/6NJ inbred mice (Stock No. 005304) to establish the colony.

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.

Allele

Symbol: Tg(CAG-OTC/CAT)4033Prab
Name: transgene insertion 4033, Peter S Rabinovitch
MGI accession ID: MGI:3695678
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Marker symbol: Tg(CAG-OTC/CAT)4033Prab
Marker name: transgene insertion 4033, Peter S Rabinovitch
Chromosome: UN
Strain of origin: C57BL/6 x (C57BL/6 x C3H)F1
Expressed genes: CAT,catalase,human
Molecular note: To generate the transgene, the 11 carboxy-terminal amino acids, including the peroxisomal localization signal, were deleted from the human catalase gene. The initiating methionine was also deleted and the first 25 amino acids of the ornithine transcarbamylase leader sequence were added to the amino terminus to target this protein product to mitochondria. The catalase cDNA construct was then cloned into a plasmid under the influence of the chicken-actin promoter/CMV enhancer (CAG). The catalase activity in the cardiac mitochondrial fraction of transgenic animals is 50 times higher than that in their wild-type littermates.