Assembly properties of human immunodeficiency virus type 1 Gag-leucine zipper chimeras: implications for retrovirus assembly.
J Virol
; 83(5): 2216-25, 2009 Mar.
Article
em En
| MEDLINE
| ID: mdl-19073719
ABSTRACT
Expression of the retroviral Gag protein leads to formation of virus-like particles in mammalian cells. In vitro and in vivo experiments show that nucleic acid is also required for particle assembly. However, several studies have demonstrated that chimeric proteins in which the nucleocapsid domain of Gag is replaced by a leucine zipper motif can also assemble efficiently in mammalian cells. We have now analyzed assembly by chimeric proteins in which nucleocapsid of human immunodeficiency virus type 1 (HIV-1) Gag is replaced by either a dimerizing or a trimerizing zipper. Both proteins assemble well in human 293T cells; the released particles lack detectable RNA. The proteins can coassemble into particles together with full-length, wild-type Gag. We purified these proteins from bacterial lysates. These recombinant "Gag-Zipper" proteins are oligomeric in solution and do not assemble unless cofactors are added; either nucleic acid or inositol phosphates (IPs) can promote particle assembly. When mixed with one equivalent of IPs (which do not support assembly of wild-type Gag), the "dimerizing" Gag-Zipper protein misassembles into very small particles, while the "trimerizing" protein assembles correctly. However, addition of both IPs and nucleic acid leads to correct assembly of all three proteins; the "dimerizing" Gag-Zipper protein also assembles correctly if inositol hexakisphosphate is supplemented with other polyanions. We suggest that correct assembly requires both oligomeric association at the C terminus of Gag and neutralization of positive charges near its N terminus.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Zíper de Leucina
/
HIV-1
/
Montagem de Vírus
/
Produtos do Gene gag do Vírus da Imunodeficiência Humana
Limite:
Humans
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article