title: Double-stranded RNA in rice: a novel RNA replicon in plants.
abstract: The entire sequence of 13952 nucleotides of a plasmid-like, double-stranded RNA (dsRNA) from rice was assembled from more than 50 independent cDNA clones. The 5' non-coding region of the coding (sense) strand spans over 166 nucleotides, followed by one long open reading frame (ORF) of 13716 nucleotides that encodes a large putative polyprotein of 4572 amino acid residues, and by a 70-nucleotide 3' non-coding region. This ORF is apparently the longest reported to date in the plant kingdom. Amino acid sequence comparisons revealed that the large putative polyprotein includes an RNA helicase-like domain and an RNA-dependent RNA polymerase (replicase)-like domain. Comparisons of the amino acid sequences of these two domains and of the entire genetic organization of the rice dsRNA with those found in potyviruses and the CHV1-713 dsRNA of chestnut blight fungus suggest that the rice dsRNA is located evolutionarily between potyviruses and the CHV1-713 dsRNA. This plasmid-like dsRNA in rice seems to constitute a novel RNA replicon in plants.
authors.affiliation: Laboratory of Molecular Cell Biology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Moriyama
authors.forename: T
authors.initials: T
authors.lastname: Nitta
authors.forename: T
authors.initials: T
authors.lastname: Fukuhara
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012275:Oryza / Q000235:genetics*; D012330:RNA, Double-Stranded; D018749:RNA, Plant / Q000737:chemistry / Q000235:genetics*; D012367:RNA, Viral / Q000737:chemistry; D012093:Replicon / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D012330:RNA, Double-Stranded; D018749:RNA, Plant; D012367:RNA, Viral; D014764:Viral Proteins