scholarly journals 3′-Azido-3′-Deoxythymidine (AZT) and AZT-Resistant Reverse Transcriptase Can Increase the In Vivo Mutation Rate of Human Immunodeficiency Virus Type 1

2000 ◽  
Vol 74 (20) ◽  
pp. 9532-9539 ◽  
Author(s):  
Louis M. Mansky ◽  
Lisa C. Bernard
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Reverse Transcriptase ◽  
Mutation Rate ◽  
Human Immunodeficiency Virus Type ◽  
Antiretroviral Drugs ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT How antiretroviral drug resistance influences human immunodeficiency virus type 1 (HIV-1) evolution is not clear. This study tested the hypothesis that antiretroviral drugs such as 3′-azido-3′-deoxythymidine (AZT) can influence the in vivo mutation rate of HIV-1. It was observed that AZT can increase the rate of HIV-1 mutation by a factor of 7 in a single round of replication. In addition, (−)2′,3′-dideoxy-3′-thiacytidine (3TC) was also found to increase the mutation rate of HIV-1 by a factor of 3. It was also found that HIV-1 drug-resistant reverse transcriptase (RT) variants can influence the in vivo mutation rate. Replication of HIV-1 with AZT-resistant RTs increased the mutation rate by as much as a factor of 3, while replication of HIV-1 with a 3TC-resistant RT (M184V) had no significant effect on the mutation rate. It was observed that only high-level, AZT-resistant RT variants could influence the in vivo mutation rate (i.e., M41L/T215Y and M41L/D67N/K70R/T215Y). In total, these observations indicate that both antiretroviral drugs and drug resistance mutations can influence the in vivo mutation rate of HIV-1.

scholarly journals Increased Multinucleoside Drug Resistance and Decreased Replicative Capacity of a Human Immunodeficiency Virus Type 1 Variant with an 8-Amino-Acid Insert in the Reverse Transcriptase

2005 ◽  
Vol 79 (6) ◽  
pp. 3536-3543 ◽  
Author(s):  
Lia van der Hoek ◽  
Nicole Back ◽  
Maarten F. Jebbink ◽  
Anthony de Ronde ◽  
Margreet Bakker ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Amino Acid ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Antiretroviral Drugs ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Resistance to antiretroviral drugs is generally conferred by specific amino acid substitutions, rather than insertions or deletions, in reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1). The exception to these findings is the amino acid insertions found in the β3-β4 loop of the RT enzyme in response to treatment with nucleoside reverse transcriptase inhibitors. This insert consists most commonly of two amino acids, but we describe in detail the evolution of a variant with an 8-amino-acid (aa) insert in a patient treated with zidovudine (ZDV) and 2′-3′-dideoxycytidine (ddC). The 24-nucleotide insert is a partial duplication of local sequences but also contains a sequence segment of unknown origin. Extensive sequence analysis of longitudinal patient samples indicated that the HIV-1 population prior to the start of therapy contained not the wild-type amino acid 215T in RT but a mixture with 215D and 215C. Treatment with ZDV and subsequent ZDV-ddC combination therapy resulted in the evolution of an HIV-1 variant with a typical ZDV resistance genotype (41L, 44D, 67N, 69D, 210W, 215Y), which was slowly replaced by the insert-containing variant (41L, 44D, insert at position 69, 70R, 210W, 215Y). The latter variant demonstrated increased resistance to a wide range of drugs, indicating that the 8-aa insert augments nucleoside analogue resistance. The gain in drug resistance of the insert variant came at the expense of a reduction in replication capacity when assayed in the absence of drugs. We compared these data with the resistance and replication properties of 133 insert-containing sequences of different individuals present in the ViroLogic database and found that the size and actual sequence of the insert at position 69 influence the level of resistance to nucleoside analogues.

scholarly journals The Interaction of Vpr with Uracil DNA Glycosylase Modulates the Human Immunodeficiency Virus Type 1 In Vivo Mutation Rate

2000 ◽  
Vol 74 (15) ◽  
pp. 7039-7047 ◽  
Author(s):  
Louis M. Mansky ◽  
Sandra Preveral ◽  
Luc Selig ◽  
Richard Benarous ◽  
Serge Benichou
Keyword(s):  
Human Immunodeficiency Virus ◽  
Mutation Rate ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Dna Glycosylase ◽  
Uracil Dna Glycosylase ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The Vpr protein of human immunodeficiency virus type 1 (HIV-1) influences the in vivo mutation rate of the virus. Since Vpr interacts with a cellular protein implicated in the DNA repair process, uracil DNA glycosylase (UNG), we have explored the contribution of this interaction to the mutation rate of HIV-1. Single-amino-acid variants of Vpr were characterized for their differential UNG-binding properties and used to trans complement vpr null mutant HIV-1. A striking correlation was established between the abilities of Vpr to interact with UNG and to influence the HIV-1 mutation rate. We demonstrate that Vpr incorporation into virus particles is required to influence the in vivo mutation rate and to mediate virion packaging of the nuclear form of UNG. The recruitment of UNG into virions indicates a mechanism for how Vpr can influence reverse transcription accuracy. Our data suggest that distinct mechanisms evolved in primate and nonprimate lentiviruses to reconcile uracil misincorporation into lentiviral DNA.

scholarly journals Screening for antiretroviral drug resistance among treatment-naive human immunodeficiency virus type 1-infected individuals in Lebanon

2014 ◽  
Vol 8 (03) ◽  
pp. 339-348
Author(s):  
Jacques M Mokhbat ◽  
Nada M. Melhem ◽  
Ziad El-Khatib ◽  
Pierre Zalloua
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Viral Load ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Newly Diagnosed ◽  
Reverse Transcriptase Inhibitors ◽  
Immunodeficiency Virus ◽  
Hiv 1

Introduction: Antiretroviral therapy (ART) has been successful at decreasing the morbidity and mortality associated with human immunodeficiency virus type 1 (HIV-1) infection. HIV-1 drug resistance (HIVDR) among ART-naive patients has been documented to compromise the success of initial therapy. This study was conducted to determine the prevalence of HIVDR mutations among newly diagnosed drug-naive HIV-infected individuals in Lebanon. Methodology: Plasma samples from 37 newly diagnosed participants at various stages of HIV-1 infection were used to determine HIV-1 RNA viral load, isolate viral RNA, and amplify DNA by RT-PCR. Purified PCR products were used to perform genotypic resistance tests. Results: The prevalence of resistance mutations to nucleoside reverse transcriptase inhibitors (NRTI), non-nucleoside reverse transcriptase inhibitors (NNRT), and protease inhibitors (PI) were 5.4%, 10.8%, and 8%, respectively. The major mutations detected in the study participants conferred resistance to NRTIs and NNRTIs recommended for HIV-1 treatment.  No significant relationship between HIV-1 viral load of participants and the mode of HIV-1 transmission or between the occurrence of HIVDR and the mode of transmission was found. Conclusions: To our knowledge, this is the first study on HIVDR mutations among newly diagnosed HIV-infected persons in Lebanon. The overall prevalence of HIVDR mutations detected in our study was 16%. Our results are important for evaluating the utility of the standard first-line regimens in use, determining the feasibility of HIVDR testing before the initiation of ART, as well as minimizing the emergence and transmission of HIVDR.

scholarly journals Coresistance to Zidovudine and Foscarnet Is Associated with Multiple Mutations in the Human Immunodeficiency Virus Type 1 Reverse Transcriptase

1998 ◽  
Vol 42 (11) ◽  
pp. 3038-3043 ◽  
Author(s):  
Gilda Tachedjian ◽  
Martyn French ◽  
John Mills
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Evolutionary Path ◽  
In Vivo Selection ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) isolates obtained from a patient with AIDS were assessed for coresistance to foscarnet and zidovudine. An HIV-1 strain (AP20) coresistant to foscarnet and zidovudine was isolated after 20 months of continuous combination therapy. The reverse transcriptase (RT) gene of AP20 had 41 substitutions which were different from the HXB2-D sequence and 9 that were different from the sequence of its foscarnet-sensitive, zidovudine-resistant progenitor virus (AP6). Six of these mutations were nonpolymorphic (T39A, V108I, K166R, K219R, K223Q, and L228R). Both strains had the conventional mutations mediating zidovudine resistance. In vivo selection may result in HIV-1 strains that are coresistant to foscarnet and zidovudine, but coresistance appears to require a complex evolutionary path and multiple RT mutations.

scholarly journals Theoretical Design of a Gene Therapy To Prevent AIDS but Not Human Immunodeficiency Virus Type 1 Infection

2003 ◽  
Vol 77 (18) ◽  
pp. 10028-10036 ◽  
Author(s):  
Leor S. Weinberger ◽  
David V. Schaffer ◽  
Adam P. Arkin
Keyword(s):  
Gene Therapy ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Antiretroviral Drugs ◽  
Set Point ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Recent reports confirm that, due to the presence of long-lived, latently infected cell populations, eradication of human immunodeficiency virus type 1 (HIV-1) from infected patients by using antiretroviral drugs will be exceedingly difficult. An alternative to virus eradication may be to use gene therapy to induce a pseudo-latent state in virus-producing cells, thus transforming HIV-1 into a lifelong, but manageable, virus. Conditionally replicating HIV-1 (crHIV-1) gene therapy vectors provide an avenue for subduing HIV-1 expression in infected cells (by creating a parasite, crHIV-1, of the parasite HIV-1), potentially reducing the HIV-1 set point and delaying AIDS onset. Development of crHIV-1 vectors has proceeded in vitro, but the requirements for a crHIV-1 vector to proliferate and persist in vivo have not been explored. We expand a widely accepted mathematical model of HIV-1 in vivo dynamics to include a crHIV-1 gene therapy virus and derive a simple criterion for designing crHIV-1 viruses that will persist in vivo. The model introduces only two new parameters—HIV-1 inhibition and crHIV-1 production—and both can be experimentally engineered and controlled. Analysis demonstrates that crHIV-1 gene therapy can indefinitely reduce HIV-1 set point to levels comparable to those achieved with highly active antiretroviral therapy, provided crHIV-1 production is more efficient than HIV-1. Paradoxically, highly efficient therapeutic inhibition of HIV-1 was found to be disadvantageous. Thus, the field may benefit by shifting the search for more potent antiviral genes toward engineering optimized therapy viruses that package ultraefficiently while downregulating viral production moderately.

scholarly journals Exploitation of the Low Fidelity of Human Immunodeficiency Virus Type 1 (HIV-1) Reverse Transcriptase and the Nucleotide Composition Bias in the HIV-1 Genome To Alter the Drug Resistance Development of HIV

2001 ◽  
Vol 75 (13) ◽  
pp. 5772-5777 ◽  
Author(s):  
Jan Balzarini ◽  
Maria-José Camarasa ◽  
Maria-Jesus Pérez-Pérez ◽  
Ana San-Félix ◽  
Sonsoles Velázquez ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Resistance Development ◽  
Nucleotide Bias ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The RNA genome of the lentivirus human immunodeficiency virus type 1 (HIV-1) is significantly richer in adenine nucleotides than the statistically equal distribution of the four different nucleotides that is expected. This compositional bias may be due to the guanine-to-adenine (G→A) nucleotide hypermutation of the HIV genome, which has been explained by dCTP pool imbalances during reverse transcription. The adenine nucleotide bias together with the poor fidelity of HIV-1 reverse transcriptase markedly enhances the genetic variation of HIV and may be responsible for the rapid emergence of drug-resistant HIV-1 strains. We have now attempted to counteract the normal mutational pattern of HIV-1 in response to anti-HIV-1 drugs by altering the endogenous deoxynucleoside triphosphate pool ratios with antimetabolites in virus-infected cell cultures. We showed that administration of these antimetabolic compounds resulted in an altered drug resistance pattern due to the reversal of the predominant mutational flow of HIV (G→A) to an adenine-to-guanine (A→G) nucleotide pattern in the intact HIV-1-infected lymphocyte cultures. Forcing the virus to change its inherent nucleotide bias may lead to better control of viral drug resistance development.

scholarly journals Suppression of Viremia and Evolution of Human Immunodeficiency Virus Type 1 Drug Resistance in a Macaque Model for Antiretroviral Therapy

2007 ◽  
Vol 81 (22) ◽  
pp. 12145-12155 ◽  
Author(s):  
Zandrea Ambrose ◽  
Sarah Palmer ◽  
Valerie F. Boltz ◽  
Mary Kearney ◽  
Kay Larsen ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Antiretroviral Therapy ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Immunodeficiency Virus ◽  
The Impact ◽  
Hiv 1

ABSTRACT Antiretroviral therapy (ART) in human immunodeficiency virus type 1 (HIV-1)-infected patients does not clear the infection and can select for drug resistance over time. Not only is drug-resistant HIV-1 a concern for infected individuals on continual therapy, but it is an emerging problem in resource-limited settings where, in efforts to stem mother-to-child-transmission of HIV-1, transient nonnucleoside reverse transcriptase inhibitor (NNRTI) therapy given during labor can select for NNRTI resistance in both mother and child. Questions of HIV-1 persistence and drug resistance are highly amenable to exploration within animals models, where therapy manipulation is less constrained. We examined a pigtail macaque infection model responsive to anti-HIV-1 therapy to study the development of resistance. Pigtail macaques were infected with a pathogenic simian immunodeficiency virus encoding HIV-1 reverse transcriptase (RT-SHIV) to examine the impact of prior exposure to a NNRTI on subsequent ART comprised of a NNRTI and two nucleoside RT inhibitors. K103N resistance-conferring mutations in RT rapidly accumulated in 2/3 infected animals after NNRTI monotherapy and contributed to virologic failure during ART in 1/3 animals. By contrast, ART effectively suppressed RT-SHIV in 5/6 animals. These data indicate that suboptimal therapy facilitates HIV-1 drug resistance and suggest that this model can be used to investigate persisting viral reservoirs.

scholarly journals Resistance to Nucleoside Analog Reverse Transcriptase Inhibitors Mediated by Human Immunodeficiency Virus Type 1 p6 Protein

2001 ◽  
Vol 75 (20) ◽  
pp. 9644-9653 ◽  
Author(s):  
Solange Peters ◽  
Miguel Muñoz ◽  
Sabine Yerly ◽  
Victor Sanchez-Merino ◽  
Cecilio Lopez-Galindez ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Drug Resistance ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Nucleoside Analog ◽  
Viral Protease ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Resistance of human immunodeficiency virus type 1 (HIV-1) to antiretroviral agents results from target gene mutation within thepol gene, which encodes the viral protease, reverse transcriptase (RT), and integrase. We speculated that mutations in genes other that the drug target could lead to drug resistance. For this purpose, the p1-p6 gag -p6 pol region of HIV-1, placed immediately upstream ofpol, was analyzed. This region has the potential to alter Pol through frameshift regulation (p1), through improved packaging of viral enzymes (p6Gag), or by changes in activation of the viral protease (p6Pol). Duplication of the proline-rich p6Gag PTAP motif, necessary for late viral cycle activities, was identified in plasma virus from 47 of 222 (21.2%) patients treated with nucleoside analog RT inhibitor (NRTI) antiretroviral therapy but was identified very rarely from drug-naı̈ve individuals. Molecular clones carrying a 3-amino-acid duplication, APPAPP (transframe duplication SPTSPT in p6Pol), displayed a delay in protein maturation; however, they packaged a 34% excess of RT and exhibited a marked competitive growth advantage in the presence of NRTIs. This phenotype is reminiscent of the inoculum effect described in bacteriology, where a larger input, or a greater infectivity of an organism with a wild-type antimicrobial target, leads to escape from drug pressure and a higher MIC in vitro. Though the mechanism by which the PTAP region participates in viral maturation is not known, duplication of this proline-rich motif could improve assembly and packaging at membrane locations, resulting in the observed phenotype of increased infectivity and drug resistance.

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