title: Evolutionary conservation supports ancient origin for Nudt16, a nuclear-localized, RNA-binding, RNA-decapping enzyme.
abstract: Nudt16p is a nuclear RNA decapping protein initially identified in Xenopus (X29) and known to exist in mammals. Here, we identified putative orthologs in 57 different organisms ranging from humans to Cnidaria (anemone/coral). In vitro analysis demonstrated the insect ortholog can bind RNA and hydrolyze the m(7)G cap from the 5'-end of RNAs indicating the Nudt16 gene product is functionally conserved across metazoans. This study also identified a closely related paralogous protein, known as Syndesmos, which resulted from a gene duplication that occurred in the tetrapod lineage near the amniote divergence. While vertebrate Nudt16p is a nuclear RNA decapping protein, Syndesmos is associated with the cytoplasmic membrane in tetrapods. Syndesmos is inactive for RNA decapping but retains RNA-binding activity. This structure/function analysis demonstrates evolutionary conservation of the ancient Nudt16 protein suggesting the existence and maintenance of a nuclear RNA degradation pathway in metazoans.
authors.affiliation: Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Taylor
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Peculis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001717:Birds / Q000235:genetics; D002467:Cell Nucleus / Q000201:enzymology*; D017124:Conserved Sequence; D004722:Endoribonucleases / Q000737:chemistry / Q000145:classification* / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D006801:Humans; D008322:Mammals / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011755:Pyrophosphatases / Q000737:chemistry / Q000145:classification; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000145:classification* / Q000235:genetics; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014714:Vertebrates / Q000235:genetics
chemical_list: D016601:RNA-Binding Proteins; D004722:Endoribonucleases; C523314:Nudt16 protein, human; D011755:Pyrophosphatases