Factors that might affect the allotopic replacement of a damaged mitochondrial DNA-encoded protein.

The human mitochondrion contains a small circular genome that codes for 13 proteins, 22 tRNAs, and 2 rRNAs. The proteins are all inner membrane bound components of complexes involved in the electron transport system and ATP formation. Mutations to any of the 13 proteins affect cellular behavior because energy production could be decreased. Investigators have attempted to find methods to correct these mutated proteins. One way is to express the mitochondrial gene in the nucleus (called allotopic expression). The newly synthesized protein would have to be imported into mitochondria and assembled into complexes. This paper reviews some of the successful attempts to achieve allotopic expression and discusses some issues that might affect the ability to have the proteins properly inserted into the inner membrane.