| Literature DB >> 9547276 |
K Akashi1, M Takenaka, S Yamaoka, Y Suyama, H Fukuzawa, K Ohyama.
Abstract
The liverwort Marchantia polymorpha mitochondrial DNA encodes almost all tRNAs required for mitochondrial translation except for the isoleucine (AUU, AUC) and threonine (ACA, ACG) codons, while the missing tRNAs are supplied in part by the nucleus and imported in mitochondria. In this paper, we report a finding of two radically different nuclear tRNAVal(AAC) genes and import of the corresponding tRNA isoacceptors in M.polymorpha mitochondria. This finding is surprising since the mtDNA encodes the gene for tRNAVal(UAC), which alone was considered sufficient for translating all four valine codons GUN by the U/N wobble mechanism. The present results suggest for the first time that the import of ncDNA-encoded tRNAs may result in decoding overlaps in plant mitochondria. The coexistence of nuclear DNA-encoded tRNAVal(AAC) and mitochondrial DNA-encoded tRNAVal(UAC) in liverwort mitochondria and the significance for the decoding mechanism as well as evolution of tRNA import are discussed.Entities:
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Year: 1998 PMID： 9547276 PMCID： PMC147542 DOI： 10.1093/nar/26.9.2168
Source DB: PubMed Journal: Nucleic Acids Res ISSN： 0305-1048 Impact factor: 16.971