title: The RNA editing pattern of cox2 mRNA is affected by point mutations in plant mitochondria.
abstract: The mitochondrial transcriptome from land plants undergoes hundreds of specific C-to-U changes by RNA editing. These events are important since most of them occur in the coding region of mRNAs. One challenging question is to understand the mechanism of recognition of a selected C residue (editing sites) on the transcript. It has been reported that a short region surrounding the target C forms the cis-recognition elements, but individual residues on it do not play similar roles for the different editing sites. Here, we studied the role of the -1 and +1 nucleotide in wheat cox2 editing site recognition using an in organello approach. We found that four different recognition patterns can be distinguished: (a) +1 dependency, (b) -1 dependency, (c) +1/-1 dependency, and (d) no dependency on nearest neighbor residues. A striking observation was that whereas a 23 nt cis region is necessary for editing, some mutants affect the editing efficiency of unmodified distant sites. As a rule, mutations or pre-edited variants of the transcript have an impact on the complete set of editing targets. When some Cs were changed into Us, the remaining editing sites presented a higher efficiency of C-to-U conversion than in wild type mRNA. Our data suggest that the complex response observed for cox2 mRNA may be a consequence of the fate of the transcript during mitochondrial gene expression.
authors.affiliation: Laboratoire de Microbiologie Cellulaire et Moléculaire et Pathogénicité, MCMP- UMR5234, Centre National de la Recherche Scientifique and Université Bordeaux Segalen. Bordeaux, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Castandet
authors.forename: Alejandro
authors.initials: A
authors.lastname: Araya
mesh_terms: D001483:Base Sequence; D003576:Electron Transport Complex IV / Q000235:genetics*; D008928:Mitochondria / Q000201:enzymology / Q000235:genetics*; D017354:Point Mutation / Q000235:genetics*; D017393:RNA Editing / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000166:cytology* / Q000201:enzymology / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; C117108:cytochrome C oxidase subunit II; D003576:Electron Transport Complex IV