mRNAs encoding mitochondrial proteins are enriched in the vicinity of mitochondria, presumably to facilitate protein transport. A possible mechanism for enrichment may involve interaction of the translocase of the mitochondrial outer membrane (TOM) complex with the precursor protein while it is translated, thereby leading to association of polysomal mRNAs with mitochondria. To test this hypothesis, we isolated mitochondrial fractions from yeast cells lacking the major import receptor, Tom20 and compared their mRNA repertoire to that of wild type cells by DNA microarrays. Most mRNAs encoding mitochondrial proteins were less associated with mitochondria, yet the extent of decrease varied among genes. Analysis of several mRNAs revealed that optimal association of Tom20-targets necessitates translating ribosomes and features within the encoded mitochondrial targeting signal. Recently, Puf3p was implicated in mRNAs' mitochondrial association through interaction with untranslated regions. We therefore constructed a tom20Delta puf3Delta double knockout strain, which demonstrated growth defects under conditions where fully functional mitochondria are required. Mislocalization effects for few tested mRNAs appeared stronger in the double knockout than in tom20Delta. Taken together, our data reveals a large-scale mRNA association mode that involves interaction of Tom20p with the translated mitochondrial targeting sequence and may be assisted by Puf3p.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|