Mean state 3 respiration rates of mitochondria isolated from hind limb muscle of homozygous Ppargc1b (peroxisome proliferative activated receptor, gamma, coactivator 1 beta) targeted mutant mice are modestly decreased. Electron microscopic analysis of brown adipose tissue does not reveal any significant abnormalities in mitochondrial volume, density, or ultrastructure. When subjected to short-term cold exposure, homozygotes are unable to maintain core body temperature to the same extent as wildtype controls. Homozygotes are born at slightly reduced rates from heterozygous crosses (reported as ~17%), but appear normal. No significant phenotype is observed under non-stressed conditions, and heart function is normal.
When combined with a Ppargc1a (peroxisome proliferative activated receptor, gamma, coactivator 1 alpha) targeted mutation (see Stock No. 009662), compound mutant animals die shortly after birth with small hearts, bradycardia, intermittent heart block and a markedly reduced cardiac output. Compound mutants also exhibit a severe abnormality in the function and density of mitochondria in heart and brown adipose tissue.
This strain may be useful in studies of cardiac development and mitochondrial function.
