scholarly journals Individual Contributions of Mutant Protease and Reverse Transcriptase to Viral Infectivity, Replication, and Protein Maturation of Antiretroviral Drug-Resistant Human Immunodeficiency Virus Type 1

2001 ◽  
Vol 75 (7) ◽  
pp. 3291-3300 ◽  
Author(s):  
Gabriela Bleiber ◽  
Miguel Munoz ◽  
Angela Ciuffi ◽  
Pascal Meylan ◽  
Amalio Telenti
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Drug Resistant ◽  
Wild Type ◽  
Protein Maturation ◽  
Antiretroviral Drug ◽  
Immunodeficiency Virus ◽  
Individual Contributions ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease (PR) and reverse transcriptase (RT) inhibitors may display impaired infectivity and replication capacity. The individual contributions of mutated HIV-1 PR and RT to infectivity, replication, RT activity, and protein maturation (herein referred to as “fitness”) in recombinant viruses were investigated by separately cloning PR, RT, and PR-RT cassettes from drug-resistant mutant viral isolates into the wild-type NL4-3 background. Both mutant PR and RT contributed to measurable deficits in fitness of viral constructs. In peripheral blood mononuclear cells, replication rates (means ± standard deviations) of RT recombinants were 72.5% ± 27.3% and replication rates of PR recombinants were 60.5% ± 33.6% of the rates of NL4-3. PR mutant deficits were enhanced in CEM T cells, with relative replication rates of PR recombinants decreasing to 15.8% ± 23.5% of NL4-3 replication rates. Cloning of the cognate RT improved fitness of some PR mutant clones. For a multidrug-resistant virus transmitted through sexual contact, RT constructs displayed a marked infectivity and replication deficit and diminished packaging of Pol proteins (RT content in virions diminished by 56.3% ± 10.7%, and integrase content diminished by 23.3% ± 18.4%), a novel mechanism for a decreased-fitness phenotype. Despite the identified impairment of recombinant clones, fitness of two of the three drug-resistant isolates was comparable to that of wild-type, susceptible viruses, suggestive of extensive compensation by genomic regions away from PR and RT. Only limited reversion of mutated positions to wild-type amino acids was observed for the native isolates over 100 viral replication cycles in the absence of drug selective pressure. These data underscore the complex relationship between PR and RT adaptive changes and viral evolution in antiretroviral drug-resistant HIV-1.

scholarly journals High Potency of Indolyl Aryl Sulfone Nonnucleoside Inhibitors towards Drug-Resistant Human Immunodeficiency Virus Type 1 Reverse Transcriptase Mutants Is Due to Selective Targeting of Different Mechanistic Forms of the Enzyme

2005 ◽  
Vol 49 (11) ◽  
pp. 4546-4554 ◽  
Author(s):  
Reynel Cancio ◽  
Romano Silvestri ◽  
Rino Ragno ◽  
Marino Artico ◽  
Gabriella De Martino ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mechanism Of Action ◽  
Drug Resistant ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Indolyl aryl sulfone (IAS) nonnucleoside inhibitors have been shown to potently inhibit the growth of wild-type and drug-resistant human immunodeficiency virus type 1 (HIV-1), but their exact mechanism of action has not been elucidated yet. Here, we describe the mechanism of inhibition of HIV-1 reverse transcriptase (RT) by selected IAS derivatives. Our results showed that, depending on the substitutions introduced in the IAS common pharmacophore, these compounds can be made selective for different enzyme-substrate complexes. Moreover, we showed that the molecular basis for this selectivity was a different association rate of the drug to a particular enzymatic form along the reaction pathway. By comparing the activities of the different compounds against wild-type RT and the nonnucleoside reverse transcriptase inhibitor-resistant mutant Lys103Asn, it was possible to hypothesize, on the basis of their mechanism of action, a rationale for the design of drugs which could overcome the steric barrier imposed by the Lys103Asn mutation.

scholarly journals Competitive Fitness of Nevirapine-Resistant Human Immunodeficiency Virus Type 1 Mutants

2004 ◽  
Vol 78 (2) ◽  
pp. 603-611 ◽  
Author(s):  
Jennifer A. Collins ◽  
M. Gregory Thompson ◽  
Elijah Paintsil ◽  
Melisa Ricketts ◽  
Joanna Gedzior ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Drug Resistant ◽  
Wild Type ◽  
Competitive Fitness ◽  
Immunodeficiency Virus ◽  
Resistant Mutants ◽  
Nevirapine Resistance ◽  
Hiv 1

ABSTRACT Determining the fitness of drug-resistant human immunodeficiency virus type 1 (HIV-1) strains is necessary for the development of population-based studies of resistance patterns. For this purpose, we have developed a reproducible, systematic assay to determine the competitive fitness of HIV-1 drug-resistant mutants. To demonstrate the applicability of this assay, we tested the fitness of the five most common nevirapine-resistant mutants (103N, 106A, 181C, 188C, and 190A), with mutations in HIV-1 reverse transcriptase (RT), singly and in combination (for a total of 31 variants) in a defined HIV-1 background. For these experiments, the 27 RT variants that produced viable virus were cocultured with wild-type virus without nevirapine. The ratios of the viral species were determined over time by utilization of a quantitative real-time RT-PCR-based assay. These experiments revealed that all of the viable variants were less fit than the wild type and demonstrated that the order of relative fitness of the single mutants tested was as follows: 103N > 181C > 190A > 188C > 106A. This order correlated with the commonality of these mutants as a result of nevirapine monotherapy. These investigations also revealed that, on average, the double mutants were less fit than the single mutants and the triple mutants were less fit than the double mutants. However, the fitness of the single and double mutants was often not predictive of the fitness of the derivative triple mutants, suggesting the presence of complex interactions between the closely aligned residues that confer nevirapine resistance. This complexity was also evident from the observation that all three of the replication-competent quadruple mutants were fitter than most of the triple mutants, and in some cases, even the double mutants. Our data suggest that, in many cases, viral fitness is the determining factor in the evolution of nevirapine-resistant mutants in vivo, that interactions between the residues that confer nevirapine resistance are complex, and that these interactions substantially affect reverse transcriptase structure and/or function.

scholarly journals The Thiocarboxanilide Nonnucleoside Inhibitor UC781 Restores Antiviral Activity of 3′-Azido-3′-Deoxythymidine (AZT) against AZT-Resistant Human Immunodeficiency Virus Type 1

1999 ◽  
Vol 43 (2) ◽  
pp. 259-263 ◽  
Author(s):  
Gadi Borkow ◽  
Dominique Arion ◽  
Mark A. Wainberg ◽  
Michael A. Parniak
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Wild Type Virus ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT N-[4-Chloro-3-(3-methyl-2-butenyloxy)phenyl]-2-methyl-3-furancarbothioamide (UC781) is an exceptionally potent nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. We found that a 1:1 molar combination of UC781 and 3′-azido-3′-deoxythymidine (AZT) showed high-level synergy in inhibiting the replication of AZT-resistant virus, implying that UC781 can restore antiviral activity to AZT against AZT-resistant HIV-1. Neither the nevirapine plus AZT nor the 2′,5′-bis-O-(t-butyldimethylsilyl)-3′-spiro-5"-(4"-amino-1",2"-oxathiole-2",2"-dioxide plus AZT combinations had this effect. Studies with purified HIV-1 reverse transcriptase (from a wild type and an AZT-resistant mutant) showed that UC781 was a potent inhibitor of the pyrophosphorolytic cleavage of nucleotides from the 3′ end of the DNA polymerization primer, a process that we have proposed to be critical for the phenotypic expression of AZT resistance. Combinations of UC781 plus AZT did not act in synergy to inhibit the replication of either wild-type virus or UC781-resistant HIV-1. Importantly, the time to the development of viral resistance to combinations of UC781 plus AZT is significantly delayed compared to the time to the development of resistance to either drug alone.

scholarly journals Identification of novel thiocarboxanilide derivatives that suppress a variety of drug-resistant mutant human immunodeficiency virus type 1 strains at a potency similar to that for wild-type virus.

1996 ◽  
Vol 40 (6) ◽  
pp. 1454-1466 ◽  
Author(s):  
J Balzarini ◽  
W G Brouwer ◽  
D C Dao ◽  
E M Osika ◽  
E De Clercq
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Effective Concentration ◽  
Mutant Virus ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Virus Strains ◽  
Hiv 1

A large variety of carboxanilide and thiocarboxanilide derivatives in which the original oxathiin or aliphatic moieties present in the prototype compounds UC84 and UC38 were replaced by an (un) substituted furanyl, thienyl, phenyl, or pyrrole entity have been evaluated for activity against wild-type human immunodeficiency virus type 1 strain IIIB [HIV-1 (IIIB)] and a series of mutant virus strains derived thereof. The mutant viruses contained either the Leu-100-->Ile, Lys-103-->Asn, Val-106-->Ala, Glu-138-->Lys, Tyr-181-->Cys, or Tyr-188-->Leu mutation in their reverse transcriptase. Several 3-(2-methylfuranyl)- and 3-(2-methylthienyl)-thiocarboxanilide ester, (thio)ether, and oxime ether derivatives showed exquisitely potent antiviral activity against wild-type HIV-1 (50% effective concentration, 0.009 to 0.021 microM). The pentenylethers of the 2-methylfuranyl and 2-methylthienyl derivatives (i.e., 313, N-[4-chloro-3-(3-methyl-2-butenyloxy)phenyl]- 2-methyl-3-furancarbothioamide or UC-781, and 314, N-[4-chloro-3-(3-methyl-2-butenyloxy)phenyl] -2-methyl-3-thiophenecarbothioamide or UC-82) proved virtually equally inhibitory for wild-type and the Ile-100, Ala-106, and Lys-138 mutant virus strains (50% effective concentration, 0.015 to 0.021 microM). Their inhibitory effect against the Asn-103 and Cys-181 reverse transcriptase mutant virus strains was decreased only four- to sevenfold compared with wildtype virus. UC-781 and UC-82 should be considered potential candidate drugs for the treatment of HIV-1-infected individuals.

scholarly journals Intracellular Substrates for the Primer-Unblocking Reaction by Human Immunodeficiency Virus Type 1 Reverse Transcriptase: Detection and Quantitation in Extracts from Quiescent- and Activated-Lymphocyte Subpopulations

2005 ◽  
Vol 49 (5) ◽  
pp. 1761-1769 ◽  
Author(s):  
Anthony J. Smith ◽  
Peter R. Meyer ◽  
Deshratn Asthana ◽  
Margarita R. Ashman ◽  
Walter A. Scott
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Wild Type ◽  
Cell Extracts ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Treatment of human immunodeficiency virus type 1 (HIV-1)-infected patients with 3′-azido-3′-deoxythymidine (AZT) selects for mutant forms of viral reverse transcriptase (RT) with increased ability to remove chain-terminating nucleotides from blocked DNA chains. We tested various cell extracts for the presence of endogenous acceptor substrates for this reaction. Cell extracts incubated with HIV-1 RT and [32P]ddAMP-terminated DNA primer/template gave rise to 32P-labeled adenosine 2′,3′-dideoxyadenosine 5′,5′′′−P1,P4-tetraphosphate (Ap4ddA), ddATP, Gp4ddA, and Ap3ddA, corresponding to the transfer of [32P]ddAMP to ATP, PPi, GTP, and ADP, respectively. Incubation with [32P]AZT monophosphate (AZTMP)-terminated primer/template gave rise to the analogous 32P-labeled AZT derivatives. Based on the rates of formation of the specific excision products, ATP and PPi levels were determined: ATP was present at 1.3 to 2.2 mM in H9 cells, macrophages, and unstimulated CD4+ or CD8+ T cells, while PPi was present at 7 to 15 μM. Under these conditions, the ATP-dependent reaction predominated, and excision by the AZT-resistant mutant RT was more efficient than wild type RT. Activated CD4+ or CD8+ T cells contained 1.4 to 2.7 mM ATP and 55 to 79 μM PPi. These cellular PPi concentrations are lower than previously reported; nonetheless, the PPi-dependent reaction predominated in extracts from activated T cells, and excision by mutant and wild-type RT occurred with similar efficiency. While PPi-dependent excision may contribute to AZT resistance in vivo, it is likely that selection of AZT-resistant mutants occurs primarily in an environment where the ATP-dependent reaction predominates.

scholarly journals Molecular Mechanisms of Tenofovir Resistance Conferred by Human Immunodeficiency Virus Type 1 Reverse Transcriptase Containing a Diserine Insertion after Residue 69 and Multiple Thymidine Analog-Associated Mutations

2004 ◽  
Vol 48 (3) ◽  
pp. 992-1003 ◽  
Author(s):  
Kirsten L. White ◽  
James M. Chen ◽  
Nicolas A. Margot ◽  
Terri Wrin ◽  
Christos J. Petropoulos ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Insertion Mutation ◽  
Wild Type ◽  
Resistance Mutations ◽  
Thymidine Analog ◽  
Immunodeficiency Virus ◽  
High Level ◽  
Hiv 1

ABSTRACT Two amino acids inserted between residues 69 and 70 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) are rare mutations that may develop in viruses containing multiple thymidine analog (zidovudine [AZT], stavudine)-associated mutations and that confer high-level resistance to all currently approved chain-terminating nucleoside and nucleotide RT inhibitors (NRTIs). The two known mechanisms of resistance to NRTIs are decreased incorporation and increased excision. The mechanism used by RT insertion mutants has not been described for tenofovir (TFV), a recently approved agent in this class. A patient-derived HIV-1 strain (strain FS-SSS) that contained an insertion mutation in a background of additional resistance mutations M41L, L74V, L210W, and T215Y was obtained. A second virus (strain FS) was derived from FS-SSS. In strain FS the insertion and T69S were reverted but the other resistance mutations were retained. The FS virus showed strong resistance to AZT but low-level changes in susceptibilities to other NRTIs and TFV. The FS-SSS virus showed reduced susceptibilities to all NRTIs including TFV. Steady-state kinetics demonstrated that the relative binding or incorporation of TFV was slightly decreased for FS-SSS RT compared to those for wild-type RT. However, significant ATP-mediated excision of TFV was detected for both mutant RT enzymes and followed the order FS-SSS RT > FS RT > wild-type RT. The presence of physiological concentrations of the +1 nucleotide inhibited TFV excision by the wild-type RT and slightly inhibited excision by the FS RT, whereas the level of excision by the FS-SSS RT remained high. Computer modeling suggests that the increased mobility of the β3-β4 loop may contribute to the high-level and broad NRTI resistance caused by the T69 insertion mutation.

scholarly journals Persistence of Wild-Type Virus and Lack of Temporal Structure in the Latent Reservoir for Human Immunodeficiency Virus Type 1 in Pediatric Patients with Extensive Antiretroviral Exposure

2002 ◽  
Vol 76 (18) ◽  
pp. 9481-9492 ◽  
Author(s):  
Christian T. Ruff ◽  
Stuart C. Ray ◽  
Patricia Kwon ◽  
Rebekah Zinn ◽  
Amanda Pendleton ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Temporal Structure ◽  
Latent Reservoir ◽  
Drug Resistant ◽  
Wild Type ◽  
Time Points ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Although highly active antiretroviral therapy (HAART) for human immunodeficiency virus type 1 (HIV-1) infection can reduce levels of HIV-1 RNA in plasma to below the limit of detection, replication-competent forms of the virus persist in all infected individuals. One form of persistence involves a stable reservoir of latent but potentially infectious virus that resides in resting memory CD4+ T cells. The mechanisms involved in maintaining this latent reservoir are incompletely understood. In the present study, we examined the dynamic characteristics of this reservoir in a cohort of children who developed drug-resistant HIV-1 as a result of extensive exposure to inadequately suppressive one- or two-drug regimens prior to the advent of HAART. We have previously shown that drug-resistant viruses selected by nonsuppressive pre-HAART regimens can enter and persist in this reservoir. We have extended these findings here by demonstrating that archival wild-type HIV-1 persists in this reservoir despite the fact that in these patients drug-resistant mutants have been favored by the selective conditions for many years. Phylogenetic analysis of replication-competent viruses persisting in resting CD4+ T cells revealed a striking lack of temporal structure in the sense that isolates obtained at later time points did not show greater sequence divergence than isolates from earlier time points. The persistence of drug-sensitive virus and the lack of temporal structure in the latent reservoir provide genetic evidence for the idea that HIV-1 can persist in a latent form free of selective pressure from antiretroviral drugs in long-lived resting memory CD4+ T cells. Although there may be other mechanisms for viral persistence, this stable pool of latently infected cells is of significant concern because of its potential to serve as a lasting source of replication-competent viruses, including the infecting wild-type form and all drug-resistant variants that have arisen subsequently.

scholarly journals Combination of Drugs and Drug-Resistant Reverse Transcriptase Results in a Multiplicative Increase of Human Immunodeficiency Virus Type 1 Mutant Frequencies

2002 ◽  
Vol 76 (18) ◽  
pp. 9253-9259 ◽  
Author(s):  
Louis M. Mansky ◽  
Dennis K. Pearl ◽  
Lisa C. Gajary
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Reverse Transcriptase ◽  
Drug Resistant ◽  
Resistance Mutations ◽  
Drug Resistance Mutations ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Mutant Frequency

ABSTRACT Replication of drug-resistant human immunodeficiency virus type 1 (HIV-1) in the presence of drug can lead to the failure of antiretroviral drug treatment. Drug failure is associated with the accumulation of drug resistance mutations. Previous studies have shown that 3′-azido-3′-deoxythymidine (AZT), (−)2′,3′-dideoxy-3′-thiacytidine (3TC), and AZT-resistant HIV-1 reverse transcriptase (RT) can increase the virus in vivo mutation rate. In this study, the combined effects of drug-resistant RT and antiretroviral drugs on the HIV-1 mutant frequency were determined. In most cases, a multiplicative effect was observed with AZT-resistant or AZT/3TC dually resistant RT and several drugs (i.e., AZT, 3TC, hydroxyurea, and thymidine) and led to increases in the odds of recovering virus mutants to over 20 times that of the HIV-1 mutant frequency in the absence of drug or drug-resistance mutations. This observation indicates that HIV-1 can mutate at a significantly higher rate when drug-resistant virus replicates in the presence of drug. These increased mutant frequencies could have important implications for HIV-1 population dynamics and drug therapy regimens.

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