RRC ID 61218
Author Yoshida A, Kawabata R, Honda T, Sakai K, Ami Y, Sakaguchi T, Irie T.
Title A Single Amino Acid Substitution within the Paramyxovirus Sendai Virus Nucleoprotein Is a Critical Determinant for Production of Interferon-Beta-Inducing Copyback-Type Defective Interfering Genomes.
Journal J Virol
Abstract One of the first defenses against infecting pathogens is the innate immune system activated by cellular recognition of pathogen-associated molecular patterns (PAMPs). Although virus-derived RNA species, especially copyback (cb)-type defective interfering (DI) genomes, have been shown to serve as real PAMPs, which strongly induce interferon-beta (IFN-β) during mononegavirus infection, the mechanisms underlying DI generation remain unclear. Here, for the first time, we identified a single amino acid substitution causing production of cbDI genomes by successful isolation of two distinct types of viral clones with cbDI-producing and cbDI-nonproducing phenotypes from the stock Sendai virus (SeV) strain Cantell, which has been widely used in a number of studies on antiviral innate immunity as a representative IFN-β-inducing virus. IFN-β induction was totally dependent on the presence of a significant amount of cbDI genome-containing viral particles (DI particles) in the viral stock, but not on deficiency of the IFN-antagonistic viral accessory proteins C and V. Comparison of the isolates indicated that a single amino acid substitution found within the N protein of the cbDI-producing clone was enough to cause the emergence of DI genomes. The mutated N protein of the cbDI-producing clone resulted in a lower density of nucleocapsids than that of the DI-nonproducing clone, probably causing both production of the DI genomes and their formation of a stem-loop structure, which serves as an ideal ligand for RIG-I. These results suggested that the integrity of mononegaviral nucleocapsids might be a critical factor in avoiding the undesirable recognition of infection by host cells.IMPORTANCE The type I interferon (IFN) system is a pivotal defense against infecting RNA viruses that is activated by sensing viral RNA species. RIG-I is a major sensor for infection with most mononegaviruses, and copyback (cb)-type defective interfering (DI) genomes have been shown to serve as strong RIG-I ligands in real infections. However, the mechanism underlying production of cbDI genomes remains unclear, although DI genomes emerge as the result of an error during viral replication with high doses of viruses. Sendai virus has been extensively studied and is unique in that its interaction with innate immunity reveals opposing characteristics, such as high-level IFN-β induction and strong inhibition of type I IFN pathways. Our findings provide novel insights into the mechanism of production of mononegaviral cbDI genomes, as well as virus-host interactions during innate immunity.
Volume 92(5)
Published 2018-3-1
DOI 10.1128/JVI.02094-17
PII JVI.02094-17
PMID 29237838
PMC PMC5809723
MeSH Amino Acid Substitution / genetics Amino Acid Substitution / immunology* Animals Cell Line DEAD Box Protein 58 Defective Viruses / genetics* Defective Viruses / immunology Female Gene Expression Regulation Genome, Viral HeLa Cells Host-Parasite Interactions / genetics Host-Parasite Interactions / immunology Humans Immunity, Innate Interferon Regulatory Factor-3 / analysis Interferon Type I / immunology Interferon-beta / metabolism* Mice Mice, Inbred C57BL Mutation Nucleocapsid / metabolism Nucleoproteins / genetics Nucleoproteins / immunology* Paramyxoviridae Infections / immunology Paramyxoviridae Infections / virology Paramyxovirinae / genetics* Paramyxovirinae / immunology* Pathogen-Associated Molecular Pattern Molecules / immunology Pathogen-Associated Molecular Pattern Molecules / metabolism RNA, Viral / genetics Sendai virus / genetics* Sendai virus / immunology Virus Replication
IF 4.324
Human and Animal Cells 293T(RCB2202)