title: trans-acting proteins involved in RNA encapsidation and viral assembly in human immunodeficiency virus type 1.
abstract: The human immunodeficiency virus type 1 gag gene product Pr55gag self-assembles when expressed on its own in a variety of eukaryotic systems. Assembly in T lymphocytes has not previously been studied, nor is it clear whether Pr55gag particles can package genomic RNA or if the Gag-Pol polyprotein is required. We have used a series of constructs that express Gag or Gag-Pol proteins with or without the viral protease in transient transfections in COS-1 cells and also expressed stably in CD4+ T cells to study this. Deletion of the p6 domain at the C terminus of protease-negative Pr55gag did not abolish particle release, while truncation of the nucleocapsid protein reduced it significantly, particularly in lymphocytes. Gag-Pol polyprotein was released from T cells in the absence of Pr55gag but did not encapsidate RNA. Pr55gag encapsidated human immunodeficiency virus type 1 RNA whether expressed in a protease-positive or protease-negative context. p6 was dispensable for RNA encapsidation. Marked differences in the level of RNA export were noted between the different cell lines.
authors.affiliation: Department of Medicine, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: J F
authors.initials: JF
authors.lastname: Kaye
authors.forename: A M
authors.initials: AM
authors.lastname: Lever
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D015683:Gene Products, gag / Q000235:genetics / Q000502:physiology*; D015684:Gene Products, pol / Q000235:genetics / Q000502:physiology; D015750:Genes, gag; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D011498:Protein Precursors / Q000235:genetics / Q000502:physiology*; D012367:RNA, Viral / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014771:Virion / Q000378:metabolism; D019065:Virus Assembly / Q000502:physiology*
chemical_list: D015683:Gene Products, gag; D015684:Gene Products, pol; D011498:Protein Precursors; D012367:RNA, Viral; D015534:Trans-Activators; C059767:p55 gag precursor protein, Human immunodeficiency virus 1