Analysis of near full-length genomic sequences of drug-resistant HIV-1 spreading among therapy-naïve individuals in Nagoya, Japan: amino acid mutations associated with viral replication activity.
ABSTRACT We analyzed a total of 12 near full-length genomes of drug-resistant HIV-1 spreading among therapy-naïve individuals in Nagoya, Japan. Genomes comprised seven protease inhibitor (PI)-resistant viruses possessing an M46I (n = 6) or L90M mutation (n = 1) and five non-nucleoside reverse transcriptase inhibitor-resistant viruses possessing a K103N mutation. All 12 viruses conserved both an H87Q mutation in the cyclophilin A-binding site of Gag p24 (capsid) and a T23N mutation in the cysteine-rich domain of Tat protein. PI-resistant viruses commonly possessed two cleavage site mutations in the p6(Pol)/protease of Pol polyprotein (F48L in p6(Pol)) and the anchor/core domains of Nef protein (L57V). These amino acid mutations represent candidates for enhancing replication activity of drug-resistant viruses and supporting expansion of such viruses in therapy-naïve individuals.
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ABSTRACT: Transmission of multiclass drug-resistant human immunodeficiency virus type 1 (HIV-1) may increase with wider use of antiretroviral therapy. To determine trends in prevalence of HIV-1 drug resistance among recently infected individuals in a geographic area with a high penetration of antiviral treatment. Consecutive case series of 225 patients referred to a San Francisco, Calif, hospital with recent HIV-1 infection from June 1996 through June 2001. Time trends in the prevalence of genotypic and phenotypic primary drug resistance. Mutations associated with resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs) steadily increased from 0% in 1996-1997 to 12 (13.2%) in 2000-2001 (P =.01). There was 1 mutation associated with protease inhibitor resistance in 1996-1997 (2.5%) and there were 7 (7.7%) in 2000-2001 (P =.25). Genotypic resistance to nucleoside reverse transcriptase inhibitors (NRTIs) initially decreased and then returned to prior levels (P =.007 for test of homogeneity). Genotypic resistance to 2 or more classes of drugs increased from 1 (2.5%) to 12 (13.2%) (P =.004), but only 1 infection (1.2%) in the latter period was resistant to all 3 classes of agents (P =.58). Primary phenotypic resistance decreased for NRTIs from 21% to 6.2% (P =.03) and increased for NNRTIs from 0 to 8 (9.9%) (P =.02). Phenotypic resistance increased for protease inhibitors from 2.6% to 6.2% (P =.32). Median time to virologic suppression (<500 copies/mL) during therapy was 12 weeks for patients with genotypic evidence of resistance compared with 5 weeks for patients with drug-sensitive infections (P =.02). The frequency of primary resistance to NNRTIs is increasing, although resistance to all available classes of antiretroviral therapy remains rare. Genotypic resistance testing in recently infected persons predicts time to viral suppression during therapy.JAMA The Journal of the American Medical Association 07/2002; 288(2):181-8. · 29.98 Impact Factor
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ABSTRACT: HIV-1 Gag protein interaction with cyclophilin A (CypA) is critical for viral fitness. Among the amino acid substitutions identified in Gag noncleavage sites in HIV-1 variants resistant to protease inhibitors, H219Q (Gatanaga, H., Suzuki, Y., Tsang, H., Yoshimura, K., Kavlick, M. F., Nagashima, K., Gorelick, R. J., Mardy, S., Tang, C., Summers, M. F., and Mitsuya, H. (2002) J. Biol. Chem. 277, 5952-5961) and H219P substitutions in the viral CypA binding loop confer the greatest replication advantage to HIV-1. These substitutions represent polymorphic amino acid residues. We found that the replication advantage conferred by these substitutions was far greater in CypA-rich MT-2 and H9 cells than in Jurkat cells and peripheral blood mononuclear cells (PBM), both of which contained less CypA. High intracellular CypA content in H9 and MT-2 cells, resulting in excessive CypA levels in virions, limited wild-type HIV-1 (HIV-1(WT)) replication and H219Q introduction into HIV-1 (HIV-1(H219Q)), reduced CypA incorporation of HIV-1, and potentiated viral replication. H219Q introduction also restored the otherwise compromised replication of HIV-1(P222A) in PBM, although the CypA content in HIV-1(H219Q/P222A) was comparable with that in HIV-1(P222A), suggesting that H219Q affected the conformation of the CypA-binding motif, rendering HIV-1 replicative in a low CypA environment. Structural modeling analyses revealed that although hydrogen bonds are lost with H219Q and H219P substitutions, no significant distortion of the CypA binding loop of Gag occurred. The loop conformation of HIV-1(P222A) was found highly distorted, although H219Q introduction to HIV-1 restored the conformation of the loop close to that of HIV-1 (P222A). The present data suggested that the effect of CypA on HIV-1 replicative (WT) ability is bimodal (both high and low CypA content limits HIV-1 replication), that the conformation of the CypA binding region of Gag is important for viral fitness, and that the function of CypA is to maintain the conformation.Journal of Biological Chemistry 02/2006; 281(2):1241-50. · 4.65 Impact Factor
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ABSTRACT: A natural amino acid substitution in the human immunodeficiency virus type 1 (HIV-1) transcriptional activator Tat increases its activity and compensates for deleterious mutations elsewhere in the Tat protein. Substitution of asparagine for threonine 23 increases Tat transactivation of the HIV-1 promoter and the binding of Tat to the cellular kinase positive transcription elongation factor b (P-TEFb). Of nine other position 23 mutations tested, only the serine substitution retained wild-type activity. Correspondingly, asparagine is the most frequent amino acid at this position in HIV-1 isolates, followed by threonine and serine. Asparagine is prevalent in Tat proteins of viruses in clades A, C, and D, which are major etiologic agents of AIDS. We suggest that selection for asparagine in position 23 confers an advantage to the virus, since it can compensate for deleterious mutations in Tat. It may also support the replication of otherwise less fit drug-resistant viruses and permit the emergence of virulent strains.Journal of Virology 09/2003; 77(15):8602-6. · 5.08 Impact Factor