title: An unexpected role for RNA in the recognition of DNA by the innate immune system.
abstract: A central function of our innate immune system is to sense microbial pathogens through the presence of their nucleic acid genomes or their transcriptional or replicative activity. In mammals, a receptor-based system is mainly responsible for the detection of these "non self" nucleic acids. Tremendous progress has been made in the past years in identifying the host constituents that are required for this intricate task. With regard to the sensing of RNA genome based pathogens by our innate immune system, a picture is emerging that includes certain families of the toll-like receptor family (TLR3, TLR7, TLR8) and the RIG-I like helicases (RIG-I, MDA5 and LGP2). Genetic loss of function studies implicate that the absence of these pathways can lead to a complete lack of recognition of certain RNA viruses. At the same time, intracellular DNA can also trigger potent innate immune responses, yet the players in this field are less clear. We and another group have recently identified a role for RNA polymerase III in the conversion of AT-rich DNA into an RNA ligand that is sensed by the RIG-I pathway. In this review article, we will discuss the mechanisms and implications of this novel pathway.
authors.affiliation: Institute for Clinical Chemistry and Pharmacology, Unit for Clinical Biochemistry, University Hospital, University of Bonn, Bonn, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Bauernfeind
authors.forename: Andrea
authors.initials: A
authors.lastname: Ablasser
authors.forename: Sarah
authors.initials: S
authors.lastname: Kim
authors.forename: Eva
authors.initials: E
authors.lastname: Bartok
authors.forename: Veit
authors.initials: V
authors.lastname: Hornung
mesh_terms: D000818:Animals; D004247:DNA / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D012313:RNA / Q000235:genetics / Q000276:immunology*; D020365:RNA Helicases / Q000378:metabolism; D014158:Transcription, Genetic; D014780:Viruses / Q000276:immunology
chemical_list: D012313:RNA; D004247:DNA; D020365:RNA Helicases