129S6/SvEv-Lias^tm1Mae/J

Stock number: 013046
Research areas: Cardiovascular Research, Developmental Biology Research, Diabetes and Obesity Research, Immunology, Inflammation and Autoimmunity Research, Metabolism Research, Neurobiology Research, Research Tools

Description

This Lias^tm1Mae mutant allele has the exons 4-6 of the of the lipoic acid synthetase (Lias) gene deleted. The deleted region encodes the functionally conserved Cys motifs of the enzyme responsible for converting octanoic acid to α-lipoic acid (also called 1,2-dithiolane-3-pentanoic acid, thioctic acid, ALA, or LA). These Lias mutant mice may be useful in studying α-lipoic acid requirements during development, mitochondrial dysfunction, and oxidative stress-related diseases such as diabetes, atherosclerosis, and neurodegenerative disorders.

Detailed description

The Lias^tm1Mae mutant allele has the exons 4-6 of the of the lipoic acid synthetase (Lias) gene deleted. The deleted region encodes the functionally conserved Cys motifs of the enzyme responsible for converting octanoic acid to α-lipoic acid (also called 1,2-dithiolane-3-pentanoic acid, thioctic acid, ALA, or LA) via insertion of a sulfur atom into the hydrocarbon chain of octanoic acid. Lias mRNA expression in heterozygous mice is approximately half of wildtype levels. Lias homozygous mice die in utero shortly after implantation. When heterozygous dams are fed an exogenous racemic α-lipoic acid diet (equal amounts of left- and right-handed enantiomers of the chiral α-lipoic acid molecule), embryonic lethality of homozygous embryos is not rescued. Heterozygous mice are viable and fertile, with a mild reduction of plasma antioxidant capacity. Inducing stress conditions (such as inflammation, hypercholesterolemia and hyperglycemia) is expected to result in significantly reduced endogenous antioxidant capacity. Specifically, heterozygous mice exhibit significantly increased reactive oxygen species (ROS) levels following lipopolysaccharide-induced sepsis. In addition, heterozygous Lias-deficiency enhances atherosclerosis in apoE-deficient male mice (see details below). These Lias mutant mice may be useful in studying α-lipoic acid requirements during development, mitochondrial dysfunction, and oxidative stress-related diseases such as diabetes, atherosclerosis, and neurodegenerative disorders.

When 129S6-Lias mutant mice are bred with 129S6-apoE mutant mice (Stock No. 014556), enhanced atherosclerosis and reduced antioxidant capacity is observed in males heterozygous for the Lias mutation and homozygous for the apoE mutation (129S6-Lias^+/-apoE^-/-). Compared to 129S6-apoE^-/- males, 129S6-Lias^+/-apoE^-/- males have significantly larger atherosclerotic lesions at the aortic sinus accompanied by enhanced oxidative stress, increased plasma cholesterol, and a transition from glucose to lipid catabolism in the liver (reduced pyruvate dehydrogenase complex activity). 129S6-Lias^+/-apoE^-/- males have significant reductions in aortic expression of antioxidant enzyme genes (including superoxide dismutase 1 and 2 (SOD1 and SOD2)) compared to 129S6-apoE^-/- males.

Development

A targeting vector was designed in the laboratory of Dr. Nobuyo Maeda (University of North Carolina at Chapel Hill) to replace exons 4-6 of the lipoic acid synthetase (Lias) gene with a reverse-oriented neomycin resistance cassette. The deleted ~3.7 kbp region encodes the functionally conserved Cys motifs of the enzyme responsible for converting octanoic acid to α-lipoic acid (also called 1,2-dithiolane-3-pentanoic acid, thioctic acid, ALA, or LA) via insertion of a sulfur atom into the hydrocarbon chain of octanoic acid. To generate mutant mice on a 129S6/SvEv genetic background, the construct was electroporated into 129S6/SvEvTac-derived W4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts and chimeric males were bred with 129S6/SvEvTac females to establish the colony. Mice heterozygous for the Lias^tm1Mae mutant allele were maintained on a 129S6/SvEvTac genetic background prior to sending to The Jackson Laboratory Repository. Upon arrival, mutant mice were maintained on the 129S6/SvEvTac genetic background by breeding heterozygous mice with wildtype mice from the colony.

Allele

Symbol: Lias^tm1Mae
Name: targeted mutation 1, Nobuyo Maeda
MGI accession ID: MGI:3604218
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Lias
Marker name: lipoic acid synthetase
Chromosome: 5
Strain of origin: 129S6/SvEvTac
Molecular note: A 3.7 kb sequence including exons 4-6 was replaced by a neomycin resistance gene. The deleted sequence encoded the functionally conserved Cys motifs, and loss of it resulted in a null allele.