Sequestration by IFIT1 Impairs Translation of 2′O-unmethylated Capped RNA

PLoS Pathogens

Christian H. Eberl¹  Christian Benda²  Philipp Hubel³  Cathleen Holze³  Matthias Habjan³  Livia Lacerda³  Angelika Mann³  Volker Thiel⁴  Cristina Gil-Cruz⁴  Eveline Kindler⁴  John Ziebuhr⁵  Andreas Pichlmair⁶ 

[1] Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried/Munich, Germany;Department of Structural Cell Biology, Max-Planck Institute of Biochemistry, Martinsried/Munich, Germany;Innate Immunity Laboratory, Max-Planck Institute of Biochemistry, Martinsried/Munich, Germany;Institute of Immunobiology, Kantonspital St. Gallen, St. Gallen, Switzerland;Institute of Medical Virology, Justus Liebig University, Giessen, Germany;Vetsuisse Faculty, University of Zürich, Zürich, Switzerland

关键词: Methylation;    RNA synthesis;    RNA viruses;    Small interfering RNAs;    RNA-binding proteins;    Affinity purification;    Protein translation;    Messenger RNA;   

DOI  :  10.1371/journal.ppat.1003663

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Viruses that generate capped RNA lacking 2′O methylation on the first ribose are severely affected by the antiviral activity of Type I interferons. We used proteome-wide affinity purification coupled to mass spectrometry to identify human and mouse proteins specifically binding to capped RNA with different methylation states. This analysis, complemented with functional validation experiments, revealed that IFIT1 is the sole interferon-induced protein displaying higher affinity for unmethylated than for methylated capped RNA. IFIT1 tethers a species-specific protein complex consisting of other IFITs to RNA. Pulsed stable isotope labelling with amino acids in cell culture coupled to mass spectrometry as well as in vitro competition assays indicate that IFIT1 sequesters 2′O-unmethylated capped RNA and thereby impairs binding of eukaryotic translation initiation factors to 2′O-unmethylated RNA template, which results in inhibition of translation. The specificity of IFIT1 for 2′O-unmethylated RNA serves as potent antiviral mechanism against viruses lacking 2′O-methyltransferase activity and at the same time allows unperturbed progression of the antiviral program in infected cells.

【 授权许可】

CC BY