title: Characterization of Bunyamwera virus defective interfering particles.
abstract: In an attempt to isolate conditional lethal amber nonsense mutants of Bunyamwera virus, five variants were found which produced small plaques on BHK and mouse L cells. Characterization of these variants by Northern blotting showed that they synthesized defective (subgenomic) RNAs derived from the L RNA segment. No subgenomic M or S segment RNAs were detected. The defective L RNAs were shown to be packaged into virus particles, and four of five preparations caused interference with the multiplication of standard virus. When defective-containing preparations were mixed with standard virus and grown in doubly infected cells a reduction in titre of standard virus of up to 400-fold was observed. Hence these preparations most probably contained defective interfering (DI) particles. Novel DI-specific polypeptides were synthesized in DI virus-infected cells. These novel proteins could be precipitated by antisera raised against either the N or C terminus, or both, of the L protein. Nucleotide sequence analysis of cloned cDNA to prominent DI RNAs in three different defective virus preparations revealed that the DI RNA in each case had suffered a single internal deletion of the L segment while retaining the 5'- and 3'-terminal sequences. The extent of the deletion ranged between 72% and 77% of the L RNA segment. Our results suggest that these DI particles may have arisen during the attempted isolation of Bunyamwera virus amber mutants on mouse L cells, since defective/subgenomic RNAs derived from the L and M segments were readily generated in mouse L cells but not in BHK cells, following infection with wild-type virus.
authors.affiliation: Medical Research Council Virology Unit, University of Glasgow, U.K.
authors.forename: A H
authors.initials: AH
authors.lastname: Patel
authors.forename: R M
authors.initials: RM
authors.lastname: Elliott
mesh_terms: D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002042:Bunyamwera virus / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D002460:Cell Line; D015342:DNA Probes; D004279:DNA, Viral / Q000096:biosynthesis; D003673:Defective Viruses / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D007739:L Cells; D051379:Mice; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010455:Peptides / Q000032:analysis; D012367:RNA, Viral / Q000032:analysis* / Q000737:chemistry; D014764:Viral Proteins / Q000032:analysis*; D014779:Virus Replication
chemical_list: D015342:DNA Probes; D004279:DNA, Viral; D010455:Peptides; D012367:RNA, Viral; D014764:Viral Proteins