RESUMO
Recombinant human immunodeficiency virus type 1 (HIV-1) containing a CRF01_AE Gag, AE-Gag62, was significantly less susceptible to protease inhibitors (PIs) than the subtype B reference strain, NL4-3; therefore, the mechanism of how AE-Gag62 reduced viral drug susceptibility to PIs was studied in this report. The results showed that the lysine residue at amino acid position 165 (K165) of AE-Gag62 played a role in reducing the drug susceptibility of the recombinant virus to PIs. In addition, K165 potentially appears more frequently in CRF01_AE viruses than in the viruses of other major HIV-1 subtypes. Although K165 had no effect on the extent of recombinant protease-mediated in vitro Gag cleavage, it enhanced the incorporation of the Gag-Pol precursor protein, p160, into virions. Taken together, these results suggest that K165 of CRF01_AE Gag affects the regulation of virion assembly or maturation, and reduces viral drug susceptibility to PIs.
Assuntos
Fármacos Anti-HIV/farmacologia , Farmacorresistência Viral Múltipla/genética , HIV-1/efeitos dos fármacos , Lisina , Inibidores de Proteases/farmacologia , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismo , Sequência de Aminoácidos , Linhagem Celular , Regulação Viral da Expressão Gênica/fisiologia , HIV-1/genética , HIV-1/metabolismo , Humanos , Dados de Sequência Molecular , Proteínas Recombinantes , Produtos do Gene gag do Vírus da Imunodeficiência Humana/química , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genéticaRESUMO
BACKGROUND: Protease (PR) inhibitors (PIs) were designed against subtype B virus of human immunodeficiency virus type 1 (HIV-1), but believed to retain its activity against most of the other subtypes. CRF01_AE PR (AE-PR) contains background mutations that are presumed to alter the drug susceptibility of PR. In addition, amino acid variations found in HIV-1 Gag potentially affect the drug susceptibility or catalytic efficiency of PR. METHODS: We studied the impact of naturally occurring amino acid substitutions found in AE-PR and CRF01_AE Gag (AE-Gag) on the drug susceptibility of PR to 9 currently available PIs, using the pNL4-3-derived luciferase reporter virus containing AE-Gag and/or AE-PR genes derived from drug treatment-naïve, HIV-1-infected Thai patients. RESULTS: Sequencing analysis revealed that several mutations were detected in deduced amino acid sequences of AE-PR and AE-Gag genes, as compared to these genes of pNL4-3. Drug susceptibility tests revealed that AE-PR showed a variety of susceptibilities to 9 PIs compared with pNL4-3 PR. In addition, AE-Gag significantly reduced the drug susceptibility of AE-PR and pNL4-3 PR. CONCLUSION: Our results suggest that amino acid variations in AE-PR and AE-Gag play roles in determining the drug susceptibility of CRF01_AE viruses to PIs.
Assuntos
Inibidores da Protease de HIV/farmacologia , Protease de HIV/química , Protease de HIV/genética , HIV-1/metabolismo , Produtos do Gene gag do Vírus da Imunodeficiência Humana/química , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genética , Sequência de Aminoácidos , Farmacorresistência Viral/genética , Regulação Viral da Expressão Gênica/fisiologia , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , HIV-1/genética , Humanos , Dados de Sequência Molecular , Mutação , Tailândia/epidemiologiaRESUMO
Axin1, a regulator of Wnt signaling, was previously identified as playing a negative role in the late phase of human immunodeficiency virus type 1 (HIV-1) replication in HeLa-derived J111 cells. In this report, we studied the molecular mechanism of how Axin1 regulates HIV-1 replication. HIV-1 transactivator, Tat-dependent viral reporter gene expression was enhanced in J111 cells transfected with small interfering RNA (siRNA) against Axin1. In addition, viral transcription was upregulated in J111 cells transfected with siRNA against Axin1. In contrast, HIV-1 gene expression was not enhanced by transfecting HeLa cells with siRNA against Axin1. The expression levels of T cell factor-4 (TCF4) and beta-catenin were higher in J111 than HeLa cells. In addition, siRNAs against TCF4 and beta-catenin inhibited the Axin1 siRNA-dependent enhancement of HIV-1 gene expression in J111 cells. These results suggest that Axin1 plays a negative role in HIV-1 transcription through the Wnt signaling pathway in J111 cells under normal cell culture conditions.