title: Host miRNA degradation by Herpesvirus saimiri small nuclear RNA requires an unstructured interacting region.
abstract: Herpesvirus saimiri, an oncogenic herpesvirus, during latency produces seven small nuclear RNAs, called the Herpesvirus saimiri U RNAs (HSUR1-7). HSUR1 mediates degradation of the host microRNA, miR-27, via a process that requires imperfect base-pairing. The decreased levels of miR-27 lead to prolonged T-cell activation and likely contribute to oncogenesis. To gain insight into HSUR1-mediated degradation of miR-27, we probed the in vivo secondary structure of HSUR1 and coupled this with bioinformatic structural analyses. The results suggest that HSUR1 adopts a conformation different than previously believed and that the region complementary to miR-27 lacks stable structure. To determine whether HSUR1 structural flexibility is important for its ability to mediate miR-27 degradation, we performed structurally informative mutagenic analyses of HSUR1. HSUR1 mutants in which the miR-27 binding site sequence is preserved, but sequestered in predicted helices, lose their ability to decrease miR-27 levels. These results indicate that the HSUR1 miR27-binding region must be available in a conformationally flexible segment for noncoding RNA function.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
authors.forename: Paulina
authors.initials: P
authors.lastname: Pawlica
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
authors.forename: Walter N
authors.initials: WN
authors.lastname: Moss
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
authors.forename: Joan A
authors.initials: JA
authors.lastname: Steitz
mesh_terms: D000818:Animals; D002144:Callithrix; D005814:Genes, Viral; D006567:Herpesvirus 2, Saimiriine / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000378:metabolism*; D012342:RNA, Small Nuclear / Q000378:metabolism*
chemical_list: D035683:MicroRNAs; D012342:RNA, Small Nuclear
keywords: HSUR1; in vivo chemical mapping; miRNA degradation element