title: Distinct role of Arabidopsis mitochondrial P-type pentatricopeptide repeat protein-modulating editing protein, PPME, in nad1 RNA editing.
abstract: The mitochondrion is an important power generator in most eukaryotic cells. To preserve its function, many essential nuclear-encoded factors play specific roles in mitochondrial RNA metabolic processes, including RNA editing. RNA editing consists of post-transcriptional deamination, which alters specific nucleotides in transcripts to mediate gene expression. In plant cells, many pentatricopeptide repeat proteins (PPRs) participate in diverse organellar RNA metabolic processes, but only PLS-type PPRs are involved in RNA editing. Here, we report a P-type PPR protein from Arabidopsis thaliana, P-type PPR-Modulating Editing (PPME), which has a distinct role in mitochondrial nad1 RNA editing via RNA binding activity. In the homozygous ppme mutant, cytosine (C)-to-uracil (U) conversions at both the nad1-898 and 937 sites were abolished, disrupting Arg(300)-to-Trp(300) and Pro(313)-to-Ser(313) amino acid changes in the mitochondrial NAD1 protein. NAD1 is a critical component of mitochondrial respiration complex I; its activity is severely reduced in the homozygous ppme mutant, resulting in significantly altered growth and development. Both abolished RNA editing and defective complex I activity were completely rescued by CaMV 35S promoter- and PPME native promoter-driven PPME genomic fragments tagged with GFP in a homozygous ppme background. Our experimental results demonstrate a distinct role of a P-type PPR protein, PPME, in RNA editing in plant organelles.
authors.affiliation: a Institute of Plant Biology, National Taiwan University , Taipei , Taiwan.|b Institute of Plant and Microbial Biology, Academia Sinica, Nankang , Taipei , Taiwan.
authors.forename: Kuan-Chieh
authors.initials: KC
authors.lastname: Leu
authors.affiliation: b Institute of Plant and Microbial Biology, Academia Sinica, Nankang , Taipei , Taiwan.
authors.forename: Ming-Hsiun
authors.initials: MH
authors.lastname: Hsieh
authors.affiliation: b Institute of Plant and Microbial Biology, Academia Sinica, Nankang , Taipei , Taiwan.
authors.forename: Huei-Jing
authors.initials: HJ
authors.lastname: Wang
authors.affiliation: a Institute of Plant Biology, National Taiwan University , Taipei , Taiwan.
authors.forename: Hsu-Liang
authors.initials: HL
authors.lastname: Hsieh
authors.affiliation: b Institute of Plant and Microbial Biology, Academia Sinica, Nankang , Taipei , Taiwan.|c Biotechnology Center, National Chung-Hsing University , Taichung , Taiwan.
authors.forename: Guang-Yuh
authors.initials: GY
authors.lastname: Jauh
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D042967:Electron Transport Complex I / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics*; D011485:Protein Binding; D017393:RNA Editing; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C538752:pentatricopeptide repeat protein, Arabidopsis; D009245:NADH Dehydrogenase; C000594053:Nad1 protein, Arabidopsis; D042967:Electron Transport Complex I
keywords: Arabidopsis; PPR; complex I activity; editing; mitochondria; nad1