Why are many mRNAs translated to the vicinity of mitochondria: a role in protein complex assembly?
The longstanding question of the presence of mitochondria-bound polysomes has been recently revisited using new approaches. Genome-wide analyses provided evidence that many genes are actually translated on mitochondria-bound polysomes and GFP-labeling techniques have shown that, in vivo, the 3'UTR sequence of these genes contains signals which can target hybrid RNA molecules to the proximity of mitochondria. Evolutionary conservation of some of these signals will be presented. Interestingly, class I mRNA which are translated on free polysomes and class II mRNA which are translated on mitochondria-bound polysomes have, mostly, eukaryotic and prokaryotic origins respectively. Using ATP2, a typical prokaryotic-derived gene, as a model for class II mRNA, we showed that its 3'UTR sequence is essential both for a correct addressing of mRNA to mitochondria proximity and to a proper production of functional ATP synthases. These different observations suggest that prokaryotic-derived genes are, like the contemporary mitochondrial genes, translated near mitochondrial membranes. In both cases this locus specific translation process might be connected to a correct complex assembly program and the cases of ATP synthase and cytochrome c oxidase complexes will be considered in this respect.
Laboratoire de Génétique Moléculaire CNRS, UMR 8541, Ecole Normale Supérieure, 46 rue d'Ulm. 75230 Paris Cedex 05, France.
A
A
Margeot
M
M
Garcia
W
W
Wang
E
E
Tetaud
J P
JP
di Rago
C
C
Jacq
D020413:3' Untranslated Regions / Q000737:chemistry / Q000235:genetics; D001483:Base Sequence; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics*; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000502:physiology
D020413:3' Untranslated Regions; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D003576:Electron Transport Complex IV; D006180:Proton-Translocating ATPases; C471230:ATP2 protein, S cerevisiae