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RNase L releases a small RNA from HCV RNA that refolds into a potent PAMP.
Title | RNase L releases a small RNA from HCV RNA that refolds into a potent PAMP. |
Publication Type | Journal Article |
Year of Publication | 2010 |
Authors | Malathi, K, Saito, T, Crochet, N, Barton, DJ, Gale, M, Silverman, RH |
Journal | RNA |
Volume | 16 |
Issue | 11 |
Pagination | 2108-19 |
Date Published | 2010 Nov |
ISSN | 1469-9001 |
Keywords | Animals, Base Sequence, Cell Line, Tumor, DEAD-box RNA Helicases, Endoribonucleases, Hepacivirus, Humans, Immunity, Innate, Membrane Proteins, Mice, Nerve Tissue Proteins, Nucleic Acid Conformation, Protein Binding, RNA, Viral, Substrate Specificity, Virus Replication |
Abstract | Triggering and propagating an intracellular innate immune response is essential for control of viral infections. RNase L is a host endoribonuclease and a pivotal component of innate immunity that cleaves viral and cellular RNA within single-stranded loops releasing small structured RNAs with 5'-hydroxyl (5'-OH) and 3'-monophosphoryl (3'-p) groups. In 2007, we reported that RNase L cleaves self RNA to produce small RNAs that function as pathogen-associated molecular patterns (PAMPs). However, the precise sequence and structure of PAMP RNAs produced by RNase L is unknown. Here we used hepatitis C virus RNA as substrate to characterize RNase L mediated cleavage products [named suppressor of virus RNA (svRNA)] for their ability to activate RIG-I like receptors (RLR). The NS5B region of HCV RNA was cleaved by RNase L to release an svRNA that bound to RIG-I, displacing its repressor domain and stimulating its ATPase activity while signaling to the IFN-β gene in intact cells. All three of these RIG-I functions were dependent on the presence in svRNA of the 3'-p. Furthermore, svRNA suppressed HCV replication in vitro through a mechanism involving IFN production and triggered a RIG-I-dependent hepatic innate immune response in mice. RNase L and OAS (required for its activation) were both expressed in hepatocytes from HCV-infected patients, raising the possibility that the OAS/RNase L pathway might suppress HCV replication in vivo. It is proposed that RNase L mediated cleavage of HCV RNA generates svRNA that activates RIG-I, thus propagating innate immune signaling to the IFN-β gene. |
DOI | 10.1261/rna.2244210 |
Alternate Journal | RNA |
PubMed ID | 20833746 |