5′-triphosphate guanosine RNAs recruit GTP-binding proteins to suppress RIG-I/IFN type I signaling. Wolczyk et al.

Published: 26 February 2026| Version 1 | DOI: 10.17632/hx3s69gc4y.1
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Description

The interferon (IFN) response is crucial for antiviral activity, but excessive or prolonged activation can drive hyperinflammation and cytokine storm, contributing to tissue damage and autoimmune disorders. The cytoplasmic pattern recognition receptor RIG-I detects viral double-stranded RNAs (dsRNAs) and endogenous polymerase III transcripts carrying a 5′-triphosphate (5′-ppp) or 5′-diphosphate (5′-pp) moiety, triggering phosphorylation of IRF3 and IFN immune response. While many viral RNAs initiate with 5′-ppp-adenosine (5′-pppA) and most endogenous Pol III transcripts in higher eukaryotes start with 5′-ppp-guanosine (5′-pppG), no apparent reason for this bias has been identified so far. Here we demonstrate that dsRNAs initiating with 5′-pppA trigger stronger RIG-I/IFN response than those starting with 5′-pppG, despite stimulating RIG-I in vitro to the same extent. Using RNA pull-down coupled with mass spectrometry, we show that several highly abundant GTP-binding proteins interact preferentially with 5′-pppG RNAs. Finally, supplementation with guanosine, which rapidly increases intracellular concentrations of GTP, decreases the difference in immunogenicity between 5′-pppG and 5′-pppA RNAs. Our findings suggest that 5′-pppG RNAs may enable certain RNA viruses and Pol III transcripts to limit detection by innate immune receptors. These results offer new insights into the sequence-dependent activation of the RIG-I/IFN pathway and have important implications for understanding evolutionary pressures on RNA sequences, RNA-driven autoimmunity, viral immunogenicity and the rational design of RNA therapeutics. Project financed under DIOSCURI, a programme initiated by the Max Planck Society, jointly managed with the National Science Centre in Poland, and mutually funded by Polish Ministry of Science and Higher Education and German Federal Ministry of Education and Research [2019/02/H/NZ1/00002 to G.M.]

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Molecular Biology, Cell Signaling, RNA, Innate Immunity, RNA-Binding Protein, Double-Stranded RNA

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