TY - JOUR
T1 - Single point mutations in the zinc finger motifs of the human immunodeficiency virus type 1 nucleocapsid alter RNA binding specificities of the Gag protein and enhance packaging and infectivity
AU - Mark-Danieli, Michal
AU - Laham, Nihay
AU - Kenan-Eichler, Michal
AU - Castiel, Asher
AU - Melamed, Daniel
AU - Landau, Meytal
AU - Bouvier, Nicole M.
AU - Evans, Matthew J.
AU - Bacharach, Eran
PY - 2005/6
Y1 - 2005/6
N2 - A specific interaction between the nucleocapsid (NC) domain of the Gag polyprotein and the RNA encapsidation signal (Ψ) is required for preferential incorporation of the retroviral genomic RNA into the assembled virion. Using the yeast three-hybrid system, we developed a genetic screen to detect human immunodeficiency virus type 1 (HIV-1) Gag mutants with altered RNA binding specificities. Specifically, we randomly mutated full-length HIV-1 Gag or its NC portion and screened the mutants for an increase in affinity for the Harvey murine sarcoma virus encapsidation signal. These screens identified several NC zinc finger mutants with altered RNA binding specificities. Furthermore, additional zinc finger mutants that also demonstrated this phenotype were made by site-directed mutagenesis. The majority of these mutants were able to produce normal virion-like particles; however, when tested in a single-cycle infection assay, some of the mutants demonstrated higher transduction efficiencies than that of wild-type Gag. In particular, the N17K mutant showed a seven- to ninefold increase in transduction, which correlated with enhanced vector RNA packaging. This mutant also packaged larger amounts of foreign RNA. Our results emphasize the importance of the NC zinc fingers, and not other Gag sequences, in achieving specificity in the genome encapsidation process. In addition, the described mutations may contribute to our understanding of HFV diversity resulting from recombination events between copackaged viral genomes and foreign RNA.
AB - A specific interaction between the nucleocapsid (NC) domain of the Gag polyprotein and the RNA encapsidation signal (Ψ) is required for preferential incorporation of the retroviral genomic RNA into the assembled virion. Using the yeast three-hybrid system, we developed a genetic screen to detect human immunodeficiency virus type 1 (HIV-1) Gag mutants with altered RNA binding specificities. Specifically, we randomly mutated full-length HIV-1 Gag or its NC portion and screened the mutants for an increase in affinity for the Harvey murine sarcoma virus encapsidation signal. These screens identified several NC zinc finger mutants with altered RNA binding specificities. Furthermore, additional zinc finger mutants that also demonstrated this phenotype were made by site-directed mutagenesis. The majority of these mutants were able to produce normal virion-like particles; however, when tested in a single-cycle infection assay, some of the mutants demonstrated higher transduction efficiencies than that of wild-type Gag. In particular, the N17K mutant showed a seven- to ninefold increase in transduction, which correlated with enhanced vector RNA packaging. This mutant also packaged larger amounts of foreign RNA. Our results emphasize the importance of the NC zinc fingers, and not other Gag sequences, in achieving specificity in the genome encapsidation process. In addition, the described mutations may contribute to our understanding of HFV diversity resulting from recombination events between copackaged viral genomes and foreign RNA.
UR - http://www.scopus.com/inward/record.url?scp=19944384581&partnerID=8YFLogxK
U2 - 10.1128/JVI.79.12.7756-7767.2005
DO - 10.1128/JVI.79.12.7756-7767.2005
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AN - SCOPUS:19944384581
SN - 0022-538X
VL - 79
SP - 7756
EP - 7767
JO - Journal of Virology
JF - Journal of Virology
IS - 12
ER -