[Nuclear mitochondrial pseudogenes]

Abstract

Transfer of genetic material from mitochondria to the nucleus and their integration into the nuclear genome is a continuous and dynamic process. Fragments of mitochondrial DNA (mtDNA) in the nuclear genome are incorporated as non-encoded sequences, which are called nuclear mitochondrial pseudogenes (NUMT-pseudogenes). At present, the formation NUMT-pseudogenes in the nuclear genome is shown in many eukaryotes. They are distributed on different chromosomes, form a "library" of mtDNA fragments, migrated into the nuclear genome and provide important information on the history of the evolution of genomes. Escape of mtDNA from the mitochondria most is associated with damage and mitophagy these organelles. The integration of mtDNA fragments into the nuclear genome may occur during repair of double strand breaks of nuclear DNA (nDNA) arising under the action of endogenous and exogenous agents. Reparation of nDNA double strand breaks with "capture" fragments of mtDNA, occurs by non-homologous end joining and a similar mechanism, but with the involvement microhomology, located on the terminal sequences. Analysis of data allows us to suppose that the rate of formation NUMT-pseudogenes will depend on the rate of double strand breaks in nDNA, activity systems, their repair, as well--the number of mtDNA fragments that have emerged from the organelles, with their further migration into the nucleus. Such situations can be expected, most often after exposure to the damaging agents, in the first place--ionizing radiation. The emergence of new NUMT-pseudogenes, obviously, is changing not only the structure of the genome in the areas of their implementation, but may have a significant impact on the realization of genetic information. Integration NUMT-pseudogenes in the nuclear genome de novo may play a role in the development of various pathologies and aging. NUMT-pseudogenes can make serious errors in analyzing free mtDNA of total cellular DNA (using PCR), as a result of their co-amplification.