title: The cox2 locus of the primitive angiosperm plant Acorus calamus: molecular structure, transcript processing and RNA editing.
abstract: Acorus calamus, or sweet flag, is a semiaquatic plant of uncertain taxonomic position. Molecular phylogenetic analysis using plastid rbcL sequences have suggested that Acorus calamus might be the most ancient surviving representative of the ancestral monocotyledonous plants. In order to provide molecular and phylogenetic data for the mitochondrial genetic system of Acorus, we have determined the structure of a mitochondrial locus, the cytochrome oxidase subunit II gene cox2. The Acorus cox2 gene harbors an unusually small group II intron, the smallest plant mitochondrial intron known to date. The transcript undergoes C-to-U RNA editing at eight sites. One of these sites is likely to play a dual functional role in both intron splicing and protein function. The 3' end of the mature transcript folds into a characteristic stem-loop structure that is presumably required for mitochondrial mRNA stability. Phylogenetic analysis of the cox2 sequence data, as well as the unusual intron structure, all support an evolutionarily isolated position for Acorus calamus.
authors.affiliation: Institut für Biologie III, Universität Freiburg, Germany.
authors.forename: F J
authors.initials: FJ
authors.lastname: Albertazzi
authors.forename: J
authors.initials: J
authors.lastname: Kudla
authors.forename: R
authors.initials: R
authors.lastname: Bock
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D003576:Electron Transport Complex IV / Q000096:biosynthesis / Q000235:genetics*; D019143:Evolution, Molecular; D017343:Genes, Plant; D007438:Introns; D019684:Magnoliopsida / Q000201:enzymology / Q000235:genetics*; D008928:Mitochondria / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D018515:Plant Leaves; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D018517:Plant Roots; D011058:Pollen; D017393:RNA Editing; D018749:RNA, Plant / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D018749:RNA, Plant; C111957:cox2 protein, Glycine soja; D003576:Electron Transport Complex IV