Rapid de novo generation of defective interfering RNA by cucumber necrosis virus mutants that do not express the 20-kDa nonstructural protein

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 88; no. 24; pp. 11153 - 11157
• Main Author: Rochon, D.M. (Agriculture Canada Research Station, Vancouver, BC, Canada)
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 15.12.1991; National Acad Sciences
• Subjects: ADN; ARN; Base Sequence; Biological and medical sciences; Capsid - genetics; CLONACION; CLONAGE; Complementary DNA; CONCOMBRE; cucumber necrosis virus; Defective Viruses - genetics; DNA, Viral - genetics; DNA, Viral - isolation & purification; EXPRESION GENICA; EXPRESSION DES GENES; Fundamental and applied biological sciences. Psychology; Gels; Genomics; Infections; Inoculum; Microbiology; Molecular Sequence Data; Molecular Weight; Mutagenesis, Site-Directed; MUTANT; MUTANTES; NECROVIRUS; Nucleic acids; NUCLEOTIDE; NUCLEOTIDOS; Oligodeoxyribonucleotides; PEPINO; Plant Viruses - genetics; Plants - genetics; RNA; RNA - genetics; RNA - isolation & purification; RNA Viruses - genetics; RNA, Viral - genetics; RNA, Viral - isolation & purification; Sequence Homology, Nucleic Acid; SINTOMAS; SYMPTOME; Symptoms; Transcriptional regulatory elements; Viral Core Proteins - genetics; Viral Nonstructural Proteins; Virology; Viruses; Virus; Tombusvirus; Attenuation; Replication; Mutation; RNA
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.88.24.11153

It is generally believed that serial passage at high multiplicity of infection (moi) is required for the generation of defective interfering (DI) particles. High levels of DI RNAs are found associated with persistent infections initiated with laboratory cultures of cucumber necrosis virus (CNV). Two synthetic CNV transcripts that were derived through site-directed mutagenesis of a highly infectious CNV cDNA clone and that do not express the CNV 20-kDa nonstructural protein were found to generate high levels of symptom-attenuating DI RNAs de novo without serial high-moi passage in transcript-inoculated plants. Such de novo generation of DI RNAs did not occur in infections initiated with wild-type transcript until at least eight serial high-moi passages. The observation that a CNV nonstructural protein mutant rapidly generates DI RNA de novo may provide insight into mechanisms that underly DI particle formation in RNA viruses in general.