Coevolution Between the Mitochondrial and Nuclear Genomes

The mitochondrion is the only organelle in animal cells with its own genome (mtDNA). Nevertheless, most mitochondrial proteins are encoded by the nuclear genome and are then imported into the mitochondria. Because animal mtDNA has an order of magnitude higher mutation rate compared to the nuclear genome, tight mitochondrial-nuclear coevolution is required to maintain mitochondrial function. Here we discuss three levels of such coevolution: protein-protein interaction within the mitochondrial oxidative phosphorylation system; nuclear-encoded protein-mtDNA-encoded RNA interactions in the mitochondrial translation system; nuclear DNA-encoded protein-mtDNA binding site interactions as part of the mitochondrial transcription and replication machineries.