title: High-frequency leader sequence switching during coronavirus defective interfering RNA replication.
abstract: A system was developed that exploited defective interfering (DI) RNAs of coronavirus to study the role of free leader RNA in RNA replication. A cDNA copy of mouse hepatitis virus DI RNA was placed downstream of the T7 RNA polymerase promoter to generate DI RNAs capable of extremely efficient replication in the presence of a helper virus. We demonstrated that, in the DI RNA-transfected cells, the leader sequence of these DI RNAs was switched to that of the helper virus during one round of replication. This high-frequency leader sequence exchange was not observed if a nine-nucleotide stretch of sequence (UUUAUAAAC) at the junction between the leader and the remaining DI sequence was deleted. This observation suggests that a free leader RNA generated from the genomic RNA of mouse hepatitis virus may participate in the replication of DI RNA.
authors.affiliation: Department of Microbiology, University of Southern California, School of Medicine, Los Angeles 90033.
authors.forename: S
authors.initials: S
authors.lastname: Makino
authors.forename: M M
authors.initials: MM
authors.lastname: Lai
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D003332:Coronaviridae / Q000235:genetics*; D003673:Defective Viruses / Q000235:genetics*; D006378:Helper Viruses / Q000235:genetics; D008969:Molecular Sequence Data; D006517:Murine hepatitis virus / Q000235:genetics; D015345:Oligonucleotide Probes; D010957:Plasmids; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D012367:RNA, Viral / Q000096:biosynthesis / Q000235:genetics; D015183:Restriction Mapping; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D012367:RNA, Viral