Distinct functions and requirements for the Cys-His boxes of the human immunodeficiency virus type 1 nucleocapsid protein during RNA encapsidation and replication.
The process of retroviral RNA encapsidation involves interaction between trans-acting viral proteins and cis-acting RNA elements. The encapsidation signal on human immunodeficiency virus type 1 (HIV-1) RNA is a multipartite structure composed of functional stem-loop structures. The nucleocapsid (NC) domain of the Gag polyprotein precursor contains two copies of a Cys-His box motif that have been demonstrated to be important in RNA encapsidation. To further characterize the role of the Cys-His boxes of the HIV-1 NC protein in RNA encapsidation, the relative efficiency of RNA encapsidation for virus particles that contained mutations within the Cys-His boxes was measured. Mutations that disrupted the first Cys-His box of the NC protein resulted in virus particles that encapsidated genomic RNA less efficiently and subgenomic RNA more efficiently than did wild-type virus. Mutations within the second Cys-His box did not significantly affect RNA encapsidation. In addition, a full complement of wild-type NC protein in virus particles is not required for efficient RNA encapsidation or virus replication. Finally, both Cys-His boxes of the NC protein play additional roles in virus replication.
Schwartz
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MD
McArdle Laboratory for Cancer Research, University of Wisconsin Medical School, Madison 53706, USA.
Fiore
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D
Panganiban
A T
AT
D000595:Amino Acid Sequence; D002213:Capsid / Q000235:genetics / Q000378:metabolism*; D036022:Capsid Proteins; D002461:Cell Line, Transformed; D003545:Cysteine / Q000378:metabolism*; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism*; D016679:Genome, Viral; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006639:Histidine / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D012367:RNA, Viral / Q000378:metabolism*; D014764:Viral Proteins; D019065:Virus Assembly; D014779:Virus Replication; D054301:gag Gene Products, Human Immunodeficiency Virus
D036022:Capsid Proteins; D015683:Gene Products, gag; C071884:NCP7 protein, Human immunodeficiency virus 1; D012367:RNA, Viral; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; D006639:Histidine; D003545:Cysteine