title: A heterologous, high-affinity RNA ligand for human immunodeficiency virus Gag protein has RNA packaging activity.
abstract: Retroviral RNA encapsidation depends on the specific binding of Gag proteins to packaging (psi) signals in genomic RNA. We investigated whether an in vitro-selected, high-affinity RNA ligand for the nucleocapsid (NC) portion of the Gag protein from human immunodeficiency virus type 1 (HIV-1) could mediate packaging into HIV-1 virions. We find that this ligand can functionally substitute for one of the Gag-binding elements (termed SL3) in the HIV-1 psi locus to support packaging and viral infectivity in cis. By contrast, this ligand, which fails to dimerize spontaneously in vitro, is unable to replace a different psi element (termed SL1) which is required for both Gag binding and dimerization of the HIV-1 genome. A single point mutation within the ligand that eliminates high-affinity in vitro Gag binding also abolishes its packaging activity at the SL3 position. These results demonstrate that specific binding of Gag or NC protein is a critical determinant of genomic RNA packaging.
authors.affiliation: Departments of Pathology, University of California, San Francisco, California 94143-0506, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Clever
authors.forename: R A
authors.initials: RA
authors.lastname: Taplitz
authors.forename: M A
authors.initials: MA
authors.lastname: Lochrie
authors.forename: B
authors.initials: B
authors.lastname: Polisky
authors.forename: T G
authors.initials: TG
authors.lastname: Parslow
mesh_terms: D001483:Base Sequence; D015683:Gene Products, gag / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D009690:Nucleic Acid Conformation; D017433:Protein Structure, Secondary; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D019065:Virus Assembly
chemical_list: D015683:Gene Products, gag; D008024:Ligands; D012367:RNA, Viral; D016601:RNA-Binding Proteins