Recognition of 5' triphosphate by RIG-I helicase requires short blunt double-stranded RNA as contained in panhandle of negative-strand virus.
Antiviral immunity is triggered by immunorecognition of viral nucleic acids. The cytosolic helicase RIG-I is a key sensor of viral infections and is activated by RNA containing a triphosphate at the 5' end. The exact structure of RNA activating RIG-I remains controversial. Here, we established a chemical approach for 5' triphosphate oligoribonucleotide synthesis and found that synthetic single-stranded 5' triphosphate oligoribonucleotides were unable to bind and activate RIG-I. Conversely, the addition of the synthetic complementary strand resulted in optimal binding and activation of RIG-I. Short double-strand conformation with base pairing of the nucleoside carrying the 5' triphosphate was required. RIG-I activation was impaired by a 3' overhang at the 5' triphosphate end. These results define the structure of RNA for full RIG-I activation and explain how RIG-I detects negative-strand RNA viruses that lack long double-stranded RNA but do contain blunt short double-stranded 5' triphosphate RNA in the panhandle region of their single-stranded genome.
Schlee
Martin
M
Institute of Clinical Chemistry and Pharmacology, University Hospital, University of Bonn, D-53127 Bonn, Germany.
Roth
Andreas
A
Hornung
Veit
V
Hagmann
Cristina Amparo
CA
Wimmenauer
Vera
V
Barchet
Winfried
W
Coch
Christoph
C
Janke
Markus
M
Mihailovic
Aleksandra
A
Wardle
Greg
G
Juranek
Stefan
S
Kato
Hiroki
H
Kawai
Taro
T
Poeck
Hendrik
H
Fitzgerald
Katherine A
KA
Takeuchi
Osamu
O
Akira
Shizuo
S
Tuschl
Thomas
T
Latz
Eicke
E
Ludwig
Janos
J
Hartmann
Gunther
G
D000818:Animals; D002478:Cells, Cultured; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000276:immunology*; D006801:Humans; D016898:Interferon-alpha / Q000096:biosynthesis / Q000276:immunology; D051379:Mice; D008817:Mice, Mutant Strains; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000276:immunology; D011122:Polyphosphates / Q000276:immunology* / Q000378:metabolism; D012328:RNA Viruses / Q000276:immunology*; D012330:RNA, Double-Stranded / Q000276:immunology* / Q000378:metabolism; D012367:RNA, Viral / Q000276:immunology* / Q000378:metabolism; D011971:Receptors, Immunologic
D016898:Interferon-alpha; D009843:Oligoribonucleotides; D011122:Polyphosphates; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D011971:Receptors, Immunologic; C452820:RIGI protein, human; C503356:Ddx58 protein, mouse; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; C005692:triphosphoric acid