Nucleocapsid protein effects on the specificity of retrovirus RNA encapsidation.
We have analyzed the roles of Gag protein nucleocapsid (NC) domains in the packaging or encapsidation of retroviral RNAs into virus particles. We found that mutation of both zinc finger motifs of the human immunodeficiency virus (HIV) NC domain reduced but did not eliminate encapsidation of the HIV viral RNA. However, the NC mutations also resulted in a three- to fourfold reduction in the specificity of RNA encapsidation, as determined by comparison of virus-associated genomic and spliced RNA levels. As a complementary approach, we replaced the NC domain of Moloney murine leukemia virus (M-MuLV) with that of HIV. Chimeric virus particles assembled efficiently, were of wild-type M-MuLV density, and cross-linked at NC cysteines. In encapsidation studies, wild-type M-MuLV precursor Gag (PrGag) proteins packaged M-MuLV transcripts more efficiently than HIV RNAs. In contrast, chimeric PrGag proteins possessing the HIV-1 NC domain in the context of the M-MuLV MA (matrix), p12, and CA (capsid) domains encapsidated HIV transcripts to a greater extent than M-MuLV transcripts. Our results support the notion that retroviral NC domains contribute toward both the efficiency and specificity of viral genomic RNA packaging.
Zhang
Y
Y
Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201-3098, USA.
Barklis
E
E
D000818:Animals; D001483:Base Sequence; D002213:Capsid / Q000302:isolation & purification / Q000378:metabolism*; D002460:Cell Line; D002522:Chlorocebus aethiops; D015683:Gene Products, gag / Q000378:metabolism*; D006678:HIV / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D007668:Kidney; D007700:Kinetics; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D012367:RNA, Viral / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012190:Retroviridae / Q000378:metabolism*; D013045:Species Specificity; D013379:Substrate Specificity; D014158:Transcription, Genetic; D014162:Transfection; D014758:Viral Core Proteins / Q000302:isolation & purification / Q000378:metabolism*; D016335:Zinc Fingers
D015683:Gene Products, gag; D009838:Oligodeoxyribonucleotides; D012367:RNA, Viral; D011994:Recombinant Proteins; D014758:Viral Core Proteins