Abstract
The structural basis for the distinction of viral RNA from abundant self RNA in the cytoplasm of virally infected cells is largely unknown. We demonstrated that the 5'-triphosphate end of RNA generated by viral polymerases is responsible for retinoic acid-inducible protein I (RIG-I)-mediated detection of RNA molecules. Detection of 5'-triphosphate RNA is abrogated by capping of the 5'-triphosphate end or by nucleoside modification of RNA, both occurring during posttranscriptional RNA processing in eukaryotes. Genomic RNA prepared from a negative-strand RNA virus and RNA prepared from virus-infected cells (but not from noninfected cells) triggered a potent interferon-alpha response in a phosphatase-sensitive manner. 5'-triphosphate RNA directly binds to RIG-I. Thus, uncapped 5'-triphosphate RNA (now termed 3pRNA) present in viruses known to be recognized by RIG-I, but absent in viruses known to be detected by MDA-5 such as the picornaviruses, serves as the molecular signature for the detection of viral infection by RIG-I.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Line
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Cells, Cultured
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Cytosol / metabolism
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Cytosol / virology
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DEAD Box Protein 58
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DEAD-box RNA Helicases / metabolism*
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DNA-Directed RNA Polymerases / metabolism
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Humans
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Interferon-alpha / biosynthesis
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Interferon-beta / biosynthesis
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Ligands
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Mice
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Monocytes / metabolism
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Oligoribonucleotides / metabolism
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Phosphates / metabolism
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Phosphorylation
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RNA / chemistry
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RNA / metabolism*
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RNA Caps / metabolism
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RNA, Double-Stranded / chemistry
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RNA, Double-Stranded / metabolism
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RNA, Viral / chemistry
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RNA, Viral / metabolism*
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Rabies virus / genetics
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Rabies virus / immunology
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Rabies virus / physiology
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Receptors, Immunologic
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Transcription, Genetic
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Transfection
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Viral Proteins / metabolism
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Virus Replication
Substances
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Interferon-alpha
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Ligands
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Oligoribonucleotides
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Phosphates
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RNA Caps
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RNA, Double-Stranded
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RNA, Viral
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Receptors, Immunologic
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Viral Proteins
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RNA
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Interferon-beta
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bacteriophage T7 RNA polymerase
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DNA-Directed RNA Polymerases
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RIGI protein, human
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DEAD Box Protein 58
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DEAD-box RNA Helicases