The unusual structure of a novel RNA replicon in rice.
A linear, plasmid-like, double-stranded RNA (dsRNA) was isolated from rice, and its entire sequence of 13,952 nucleotides (nt) was determined. The dsRNA encodes a single, unusually long, open reading frame (13,716 nt, 4,572 amino acid residues), which includes an RNA helicase-like domain and an RNA-dependent RNA polymerase-like domain. A series of Northern hybridization and primer extension experiments revealed that the coding (sense) strand of the dsRNA contains a discontinuity (nick) at a position 1,211 nt (or 1,256 nt) from the 5' end. This discontinuity divides not only the coding strand of dsRNA molecule into a 1,211-nt fragment and a 12,741-nt fragment (or a 1,256-nt fragment and a 12,696-nt fragment) but also divides the long open reading frame into a 5' part of 1,045 nt (348 amino acid residues) and a 3' part of 12,671 nt (4,224 amino acid residues) or a 5' part of 1,090 nt (363 amino acid residues) and a 3' part of 12,626 nt (4,209 amino acid residues). It seems likely that almost all dsRNA molecules in rice plants contain such a discontinuity. This rice dsRNA appears to be a novel and unique RNA replicon.
Fukuhara
T
T
Laboratory of Molecular Cell Biology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Japan.
Moriyama
H
H
Nitta
T
T
D001483:Base Sequence; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides; D012275:Oryza / Q000235:genetics*; D012330:RNA, Double-Stranded / Q000737:chemistry / Q000235:genetics; D018749:RNA, Plant / Q000737:chemistry / Q000235:genetics*; D012093:Replicon / Q000235:genetics*
D009838:Oligodeoxyribonucleotides; D012330:RNA, Double-Stranded; D018749:RNA, Plant