Human Immunodeficiency Virus Type 2 Reverse Transcriptase Activity in Model Systems That Mimic Steps in Reverse Transcription

Post, Klara; Guo, Jianhui; Howard, Kathryn J.; Powell, Michael D.; Miller, Jennifer T.; Hizi, Amnon; Grice, Stuart F. J. Le; Levin, Joseph

doi:10.1128/jvi.77.13.7623-7634.2003

Cited by 14 publications

(17 citation statements)

References 72 publications

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“…RT from 98CN009 was the least efficient enzyme in the panel for all three activities. Consistent with previous reports (14,27,49,56), the DNA polymerase and RNase H activities of RT from the HIV-2 strain EHO-287 were significantly less than those of most of the HIV-1 RTs.…”

Section: Methodssupporting

confidence: 80%

“…Six of the clones in the panel (94CY017.41, 92UG021, RU570, US, TAN1B, and EHO-287) represent the first cloning, expression, and purification of active RT enzymes from viral isolates of the corresponding clades. Where enzymatic activities of these isolates or close relatives have been reported separately (functional comparisons involving RTs [14,27,49,55]), our results are consistent with previous observations. Although one or two individual clones from within a given clade cannot represent the full range of enzymatic activities or drug sensitivities across the entire clade, the recombinant RT panel described here provides a useful cross section of natural lentiviral genetic diversity.…”

Section: Figsupporting

confidence: 83%

“…(Pan troglodytes troglodytes) and the 89% amino acid identity between RTs from HIV-2 group A and sooty mangabey SIV illustrate the more proximal relationships between the two HIV types and the SIV taxa from which they originated. The HIV-1 enzymes are, in general, slightly more active than their HIV-2 counterparts (14,27,49,56), which has been proposed to contribute to the greater virulence of the HIV-1 strains than of the HIV-2 strains (19,44). Many of the same factors that drive rapid viral evolution and diversification of the M group (7,8,17,40,43) have also contributed to the rapid appearance of drug resistance mutations in the RT and protease (PR) genes.…”

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confidence: 99%

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Cross-Clade Inhibition of Recombinant Human Immunodeficiency Virus Type 1 (HIV-1), HIV-2, and Simian Immunodeficiency Virus SIVcpz Reverse Transcriptases by RNA Pseudoknot Aptamers

Held

Kissel

Thacker

et al. 2007

J Virol

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Reverse transcriptase (RT) remains a primary target in therapies directed at human immunodeficiency virus type 1 (HIV-1). RNA aptamers that bind RT from HIV-1 subtype B have been shown to protect human cells from infection and to reduce viral infectivity, but little is known about the sensitivity of the inhibition to amino sequence variations of the RT target. Therefore, we assembled a panel of 10 recombinant RTs from phylogenetically diverse lentiviral isolates (including strains of HIV-1, simian immunodeficiency virus SIVcpz, and HIV-2). After validating the panel by measuring enzymatic activities and inhibition by small-molecule drugs, dose-response curves for each enzyme were established for four pseudoknot RNA aptamers representing two structural subfamilies. All four aptamers potently inhibited RTs from multiple HIV-1 subtypes. For aptamers carrying family 1 pseudoknots, natural resistance was essentially all-or-none and correlated with the identity of the amino acid at position 277. In contrast, natural resistance to aptamers carrying the family 2 pseudoknots was much more heterogeneous, both in degree (gradation of 50% inhibitory concentrations) and in distribution across clades. Site-directed and subunit-specific mutagenesis identified a common R/K polymorphism within the p66 subunit as a primary determinant of resistance to family 1, but not family 2, pseudoknot aptamers. RNA structural diversity therefore translates into a nonoverlapping spectrum of mutations that confer resistance, likely due to differences in atomic-level contacts with RT.The reverse transcriptases (RTs) of the human and simian immunodeficiency viruses (HIVs and SIVs, respectively) are encoded by the viral pol gene and are expressed from viral mRNA as part of the multifunctional Gag-Pol polyprotein. Mature RT is the product of proteolytic processing of the polyprotein, first into an asymmetric homodimer and then into the mature heterodimer (21). Due to its central role in HIV type 1 (HIV-1) replication and the early clinical availability of anti-RT compounds, RT has long been an established therapeutic target. Of the 22 anti-HIV compounds currently approved by the U.S. Food and Drug Administration, 15 target the viral RT (60). The nucleoside analogue RT inhibitors (NRTIs) are deoxynucleoside triphosphate analogues that result in chain termination when incorporated by RT into a growing DNA strand. The nonnucleoside RT inhibitors (NNRTIs) bind RT near the active site and disrupt enzymatic activity by allosteric inhibition (38, 59). The search for new anti-RT compounds is fueled by cytotoxicity and clinically selected resistance-resulting from drug exclusion or from postincorporation excision (45)-which are persistent problems for both classes of RT inhibitors.Nucleic acid aptamers, ribozymes, antisense RNA, and small interfering RNA exhibit potent antiviral effects and are under development as potential gene therapy adjuvants to smallmolecule therapeutics (25,34), and several of these have recently entered into clinical trials (1,39,4...

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Section: Methodssupporting

confidence: 80%

Section: Figsupporting

confidence: 83%

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confidence: 99%

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Cross-Clade Inhibition of Recombinant Human Immunodeficiency Virus Type 1 (HIV-1), HIV-2, and Simian Immunodeficiency Virus SIVcpz Reverse Transcriptases by RNA Pseudoknot Aptamers

Held

Kissel

Thacker

et al. 2007

J Virol

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“…In another case, F214L occurred at least 2 months after the Q151M mutation. At position 227 in the primer grip region [Post et al, 2003], a tyrosine was observed in 91% of sequences from HIV-2-treated patients and in 50% of sequences from untreated patients (P < 0.05). Note, however, that amino acid substitution F227Y was selected in only one patient during the longitudinal analysis.…”

Section: Identification Of Suspected Nrti-resistance Mutationsmentioning

confidence: 98%

Polymorphism and drug-selected mutations in the reverse transcriptase gene of HIV-2 from patients living in southeastern France

Colson¹,

Henry²,

Tivoli³

et al. 2005

J. Med. Virol.

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Few data are available about the susceptibility and the genotypic resistance pattern of human immunodeficiency virus type 2 (HIV-2) to nucleoside reverse transcriptase inhibitors (NRTIs). The HIV-2 reverse transcriptase (RT) gene from 25 HIV-2-infected patients followed-up in Marseilles and the surrounding area was analyzed. The aims of this study were to characterize the polymorphism of HIV-2 RT in the absence of drug, to determine whether it naturally harbors codons associated with drug-resistance in HIV-1, and to identify mutations emerging under NRTI-selective pressure. Fourteen patients had never undergone antiretroviral therapy and 11 received NRTI. Seventy sequences were analyzed. In untreated patients, 12 spots of high natural polymorphism (at positions 10, 11, 20, 43, 104, 121, 135, 162, 176, 180, 200, and 227) were observed; 4 of them were specific of HIV-2 (10, 176, 180, 227). Moreover, results showed four positions that could be associated with natural resistance to NRTI (75I, 118I, 219E, and perhaps 215S), in addition to those described previously for non-nucleoside reverse transcriptase inhibitors (NNRTIs) (181I, 188L, 190A). In HIV-2-infected patients receiving NRTI-containing therapies, specific genotypic patterns were observed with a high frequency of mutation Q151M (in 45% of patients) often associated with 70R, 115F, 214L, and/or 223R, which might compose an HIV-2 multi-NRTI resistance complex. Four newly or rarely described NRTI-selected mutations were observed: I5V, K35R, F214L, and K223R. As in HIV-1, substitution M184V was found in 3TC-treated patients. In conclusion, these findings highlight the need for specific guidelines for determining genotypic resistance and treatment of HIV-2.

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“…The frequency of RT switching from one RNA template to the other RNA depends on the balance between polymerase and RNase H activities, as proposed by the dynamic copy choice model (34). The RNase H activity of HIV-2 was also shown to be much lower than that of HIV-1 in vitro (56), although a more recent study indicated that they are comparable (48). If HIV-1 and HIV-2 differ in the balance of polymerase and RNase H activities in RT, then the RT molecules of these two viruses may switch templates at different frequencies and alter the observed recombination rates.…”

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confidence: 95%

High Frequency of Genetic Recombination Is a Common Feature of Primate Lentivirus Replication

Chen

Powell

2006

J Virol

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Recent studies indicate that human immunodeficiency virus type 1 (HIV-1) recombines at exceedingly high rates, approximately 1 order of magnitude more frequently than simple gammaretroviruses such as murine leukemia virus and spleen necrosis virus. We hypothesize that this high frequency of genetic recombination is a common feature of primate lentiviruses. Alternatively, it is possible that HIV-1 is unique among primate lentiviruses in possessing high recombination rates. Among other primate lentiviruses, only the molecular mechanisms of HIV-2 replication have been extensively studied. There are reported differences between the replication mechanisms of HIV-1 and those of HIV-2, such as preferences for RNA packaging in cis and properties of reverse transcriptase and RNase H activities. These biological disparities could lead to differences in recombination rates between the two viruses. Currently, HIV-1 is the only primate lentivirus in which recombination rates have been measured. To test our hypothesis, we established recombination systems to measure the recombination rates of two other primate lentiviruses, HIV-2 and simian immunodeficiency virus from African green monkeys (SIVagm), in one round of viral replication. We determined that, for markers separated by 588, 288, and 90 bp, HIV-2 recombined at rates of 7.4%, 5.5%, and 2.4%, respectively, whereas SIVagm recombined at rates of 7.8%, 5.6%, and 2.7%, respectively. These high recombination rates are within the same range as the previously measured HIV-1 recombination rates. Taken together, our results indicate that HIV-1, HIV-2, and SIVagm all possess high recombination frequencies; hence, the high recombination potential is most likely a common feature of primate lentivirus replication.

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Human Immunodeficiency Virus Type 2 Reverse Transcriptase Activity in Model Systems That Mimic Steps in Reverse Transcription

Cited by 14 publications

References 72 publications

Cross-Clade Inhibition of Recombinant Human Immunodeficiency Virus Type 1 (HIV-1), HIV-2, and Simian Immunodeficiency Virus SIVcpz Reverse Transcriptases by RNA Pseudoknot Aptamers

Cross-Clade Inhibition of Recombinant Human Immunodeficiency Virus Type 1 (HIV-1), HIV-2, and Simian Immunodeficiency Virus SIVcpz Reverse Transcriptases by RNA Pseudoknot Aptamers

Polymorphism and drug-selected mutations in the reverse transcriptase gene of HIV-2 from patients living in southeastern France

High Frequency of Genetic Recombination Is a Common Feature of Primate Lentivirus Replication

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