The increase in mitochondrial DNA copy number in the tissues of gamma-irradiated mice.
Changes in the number of mitochondrial DNA (mtDNA) copies in the brain and spleen tissues of gamma-irradiated (3 Gy) mice were studied by comparative analysis of the long-extension PCR products of mtDNA (15.9 kb) and a fragment of the cluster nuclear beta-globin gene (8.7 kb) amplified simultaneously in one and the same test-tube within total DNA. The analysis showed that, compared to the nuclear beta-globin gene, an increase in mtDNA copy number (polyploidization) took place in the brain and spleen cells of mice exposed to gamma-radiation. This data led to the suggestion that the major mechanism for maintenance of the mitochondrial genome, which is constantly damaged by endogenous ROS and easily affected by ionizing radiation or other exogenous factors, is the induction of synthesis of new mtDNA copies on intact or little affected mtDNA templates because the repair systems in the mitochondria function at a low level of efficiency.
Malakhova
Ludmila
L
Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, RAS, Pushchino, Moscow Region, 142290, Russia.
Bezlepkin
Vladimir G
VG
Antipova
Valeria
V
Ushakova
Tat'yana
T
Fomenko
Ludmila
L
Sirota
Nikolai
N
Gaziev
Azhub I
AI
D000818:Animals; D001921:Brain / Q000378:metabolism / Q000528:radiation effects; D004272:DNA, Mitochondrial / Q000235:genetics*; D005720:Gamma Rays; D018628:Gene Dosage / Q000528:radiation effects*; D050259:Genes, Mitochondrial / Q000235:genetics; D005914:Globins / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D016133:Polymerase Chain Reaction; D013154:Spleen / Q000378:metabolism / Q000528:radiation effects
D004272:DNA, Mitochondrial; D005914:Globins