Diversity and evolution of mitochondrial translation apparatus

Abstract

The evolution of mitochondria proceeded independently in different eukaryotic lines, reflected in the diversity of mitochondrial genomes and mechanisms of their expression observed in different eukaryotic species. Mitochondria lost most of the genes of their bacterial ancestor, partially transferred them to the nucleus or completely eliminated. However, the mitochondria of almost all eukaryotic cells retain relatively small genomes, as well as their replication, transcription, and translation apparatuses. Dependence on the nuclear genome, features of mitochondrial transcripts, and the necessity to synthesize highly hydrophobic membrane proteins led to a number of significant changes in translation apparatus derived from the bacterial ancestor. It retained the basic structure necessary for protein synthesis but became more specialized and labile. In this review, we consider what changes take place during the initiation of mitochondrial translation, and how the evolution of mitochondria affected the functions of the main factors initiating protein biosynthesis in these organelles.