title: The African swine fever virus g5R protein possesses mRNA decapping activity.
abstract: The African Swine Fever Virus (ASFV) encodes a single Nudix enzyme in its genome, termed the g5R protein (g5Rp). Nudix phosphohydrolases cleave a variety of substrates, such as nucleotides and diphosphoinositol polyphosphates. Previously, ASFV g5Rp was shown to hydrolyze diphosphoinositol polyphosphates and GTP, but was unable to cleave methylated mRNA cap analogues. In vaccinia virus (VACV), a distant relative of ASFV, the D9 and D10 Nudix enzymes were shown to cleave the mRNA cap, but only when the cap was attached to an RNA body. Here, we show that recombinant ASFV g5Rp hydrolyzes the mRNA cap when tethered to an RNA moiety, liberating m(7)GDP as a product. Mutations in the Nudix motif abolished mRNA decapping activity, confirming that g5Rp was responsible for cap cleavage. The decapping activity of g5Rp was potently inhibited by excess uncapped RNA but not by methylated cap analogues, suggesting that substrate recognition occurs by RNA binding.
authors.affiliation: McDaniel College, 2 College Hill, Eaton Hall, Room 212, Westminster, MD 21157, USA. sparrish@mcdaniel.edu
authors.forename: Susan
authors.initials: S
authors.lastname: Parrish
authors.forename: Megan
authors.initials: M
authors.lastname: Hurchalla
authors.forename: Shin-Wu
authors.initials: SW
authors.lastname: Liu
authors.forename: Bernard
authors.initials: B
authors.lastname: Moss
mesh_terms: D000358:African Swine Fever Virus / Q000502:physiology*; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D011755:Pyrophosphatases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*; D000096964:Nudix Hydrolases
chemical_list: D004722:Endoribonucleases; D050505:Mutant Proteins; D011755:Pyrophosphatases; D012333:RNA, Messenger; D014764:Viral Proteins; D000096964:Nudix Hydrolases; C030052:mRNA decapping enzymes
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