Analysis of human immunodeficiency virus type 1 Gag dimerization-induced assembly.
The nucleocapsid (NC) domains of retrovirus precursor Gag (PrGag) proteins play an essential role in virus assembly. Evidence suggests that NC binding to viral RNA promotes dimerization of PrGag capsid (CA) domains, which triggers assembly of CA N-terminal domains (NTDs) into hexamer rings that are interconnected by CA C-terminal domains. To examine the influence of dimerization on human immunodeficiency virus type 1 (HIV-1) Gag protein assembly in vitro, we analyzed the assembly properties of Gag proteins in which NC domains were replaced with cysteine residues that could be linked via chemical treatment. In accordance with the model that Gag protein pairing triggers assembly, we found that cysteine cross-linking or oxidation reagents induced the assembly of virus-like particles. However, efficient assembly also was observed to be temperature dependent or required the tethering of NTDs. Our results suggest a multistep pathway for HIV-1 Gag protein assembly. In the first step, Gag protein pairing through NC-RNA interactions or C-terminal cysteine linkage fosters dimerization. Next, a conformational change converts assembly-restricted dimers or small oligomers into assembly-competent ones. At the final stage, final particle assembly occurs, possibly through a set of larger intermediates.
Alfadhli
Ayna
A
Vollum Institute and Department of Microbiology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97201, USA.
Dhenub
Tenzin Choesang
TC
Still
Amelia
A
Barklis
Eric
E
D004279:DNA, Viral / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D014771:Virion; D019065:Virus Assembly / Q000502:physiology*; D054301:gag Gene Products, Human Immunodeficiency Virus
D004279:DNA, Viral; D015683:Gene Products, gag; D054301:gag Gene Products, Human Immunodeficiency Virus; C083868:gag protein p1, Human immunodeficiency virus