title: Subgenomic mRNA transcription in tobacco necrosis virus.
abstract: Tobacco necrosis virus-D (TNV-D), a positive-strand RNA Necrovirus in the family Tombusviridae, transcribes two subgenomic (sg) mRNAs during infections. We have investigated the strategy used by TNV-D in this process and uncovered evidence that it employs a premature termination (PT) mechanism for the transcription of its sg mRNAs. Structural and mutational analysis of the TNV-D genome identified local RNA structures upstream from transcriptional initiation sites that functioned in the plus-strand as attenuation structures and mediated the production of sg mRNA-sized minus-strands. Other evidence in support of a PT mechanism included the ability to uncouple minus-strand sg RNA production from plus-strand sg mRNA synthesis and the sequence similarities observed between the sg mRNA promoter and that for the viral genome. Accordingly, our results indicate that the necrovirus TNV-D, like several other genera in the family Tombusviridae, uses a PT mechanism for transcription of its sg mRNAs.
authors.affiliation: Department of Biology, York University, Toronto, Ontario, Canada.
authors.forename: Sadaf D
authors.initials: SD
authors.lastname: Jiwan
authors.forename: Baodong
authors.initials: B
authors.lastname: Wu
authors.forename: K Andrew
authors.initials: KA
authors.lastname: White
mesh_terms: D001483:Base Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012333:RNA, Messenger / Q000096:biosynthesis*; D012367:RNA, Viral / Q000096:biosynthesis*; D014026:Nicotiana / Q000821:virology*; D019183:Tombusviridae / Q000502:physiology*; D014158:Transcription, Genetic; D014779:Virus Replication
chemical_list: D012333:RNA, Messenger; D012367:RNA, Viral