title: Characterization of PA-N terminal domain of Influenza A polymerase reveals sequence specific RNA cleavage.
abstract: Influenza virus uses a unique cap-snatching mechanism characterized by hijacking and cleavage of host capped pre-mRNAs, resulting in short capped RNAs, which are used as primers for viral mRNA synthesis. The PA subunit of influenza polymerase carries the endonuclease activity that catalyzes the host mRNA cleavage reaction. Here, we show that PA is a sequence selective endonuclease with distinct preference to cleave at the 3' end of a guanine (G) base in RNA. The G specificity is exhibited by the native influenza polymerase complex associated with viral ribonucleoprotein particles and is conferred by an intrinsic G specificity of the isolated PA endonuclease domain PA-Nter. In addition, RNA cleavage site choice by the full polymerase is also guided by cap binding to the PB2 subunit, from which RNA cleavage preferentially occurs at the 12th nt downstream of the cap. However, if a G residue is present in the region of 10-13 nucleotides from the cap, cleavage preferentially occurs at G. This is the first biochemical evidence of influenza polymerase PA showing intrinsic sequence selective endonuclease activity.
authors.affiliation: Hoffmann-La Roche Inc., Virology Discovery, Nutley, NJ 07110, USA, Savira pharmaceuticals GmbH, Veterinaerplatz 1/IA, A-1210, Vienna, Austria, European Molecular Biology Laboratory, Grenoble Outstation, 6 rue Jules Horowitz, BP181, 38042 Grenoble Cedex 9, France, Unit of Virus Host Cell Interactions, University Grenoble Alpes-EMBL-CNRS, 6 rue Jules Horowitz, BP181, 38042 Grenoble Cedex 9, France and RiboScience LLC, 3901 Laguna Avenue, Palo Alto, CA 94306, USA.
authors.forename: Kausiki
authors.initials: K
authors.lastname: Datta
authors.forename: Andrea
authors.initials: A
authors.lastname: Wolkerstorfer
authors.forename: Oliver H J
authors.initials: OH
authors.lastname: Szolar
authors.forename: Stephen
authors.initials: S
authors.lastname: Cusack
authors.forename: Klaus
authors.initials: K
authors.lastname: Klumpp
mesh_terms: D001483:Base Sequence; D004722:Endoribonucleases / Q000737:chemistry / Q000378:metabolism*; D009980:Influenza A virus / Q000201:enzymology*; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry; D012315:RNA Caps / Q000378:metabolism; D059367:RNA Cleavage; D012324:RNA-Dependent RNA Polymerase / Q000737:chemistry / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D013379:Substrate Specificity; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: C061290:PA protein, influenza viruses; D012315:RNA Caps; D012261:Ribonucleoproteins; D014764:Viral Proteins; D012313:RNA; D012324:RNA-Dependent RNA Polymerase; D004722:Endoribonucleases