title: Alfalfa mosaic virus coat protein bridges RNA and RNA-dependent RNA polymerase in vitro.
abstract: Alfalfa mosaic virus (AMV) RNA replication requires the viral coat protein (CP). AMV CP is an integral component of the viral replicase; moreover, it binds to the viral RNA 3'-termini and induces the formation of multiple new base pairs that organize the RNA conformation. The results described here suggest that AMV coat protein binding defines template selection by organizing the 3'-terminal RNA conformation and by positioning the RNA-dependent RNA polymerase (RdRp) at the initiation site for minus strand synthesis. RNA-protein interactions were analyzed by using a modified Northwestern blotting protocol that included both viral coat protein and labeled RNA in the probe solution ("far-Northwestern blotting"). We observed that labeled RNA alone bound the replicase proteins poorly; however, complex formation was enhanced significantly in the presence of AMV CP. The RNA-replicase bridging function of the AMV CP may represent a mechanism for accurate de novo initiation in the absence of canonical 3' transfer RNA signals.
authors.affiliation: Harvard-MIT Division of Health Sciences and Technology and Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Vienna L
authors.initials: VL
authors.lastname: Reichert
authors.forename: Mehee
authors.initials: M
authors.lastname: Choi
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Petrillo
authors.forename: Lee
authors.initials: L
authors.lastname: Gehrke
mesh_terms: D017794:Alfalfa mosaic virus / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D001483:Base Sequence; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins; D046911:Macromolecular Substances; D012367:RNA, Viral; D011994:Recombinant Proteins; D012324:RNA-Dependent RNA Polymerase