RNA delivery into mitochondria

Mitochondria, though containing their own genome, import the vast majority of their macromolecular components from the cytoplasm. If the mechanisms of pre-protein import are well understood, the import of nuclear-coded RNAs i nto mitochondria was investigated to a much lesser extent. This targeting, if not universal, is widely spread among species. The origin and the mechan isms of RNA import seem to differ from one system to another and striking d ifferences are observed even in closely related species. We describe data c oncerning the Various experimental systems of studying RNA import with emph asis on the model of the yeast Saccharomyces cerevisiae, which was studied in our laboratory. We compare various requirements of RNA import into mitoc hondria in different species and demonstrate that this pathway can be trans ferred from yeast to human cells, in which tRNAs normally are not imported. We speculate on the possibility to use RNA import for biomedical purposes. (C) 2001 Elsevier Science B.V. All rights reserved.