Vpr and HIV-1 disease progression: R77Q mutation is associated with long-term control of HIV-1 infection in different groups of patients
Mologni, Danielaa; Citterio, Paolaa; Menzaghi, Barbaraa; Poma, Barbara Zanonea; Riva, Chiaraa; Broggini, Valentinaa; Sinicco, Alessandroc; Milazzo, Lauraa; Adorni, Fulviob; Rusconi, Stefanoa; Galli, Massimoa; Riva, Agostinoa; for the rHoPeS Group
From the aInstitute of Infectious and Tropical Diseases, University of Milan, L. Sacco Hospital, Milan
bInstitute of Biomedical Technologies–National Research Council, Milan
cClinica di Malattie Infettive, Amedeo di Savoia Hospital, Turin, Italy.
Received 28 April, 2005
Revised 1 July, 2005
Accepted 24 August, 2005
Correspondence to Dr Agostino Riva, Institute of Infectious and Tropical Diseases, University of Milan, L. Sacco Hospital, Via GB Grassi 74, 20157 Milan, Italy. E-mail: firstname.lastname@example.org
Background: Vpr (viral protein R) is a 96 amino acids soluble protein that is expressed late during viral replication. Recent studies have focused on the role of a mutation at position 77 that might be associated with the condition of long-term non-progression, but data are still controversial.
Patients and methods: Fifteen long-term non-progressors (LTNP), 19 therapy-naive HIV-1-infected patients with progressive disease (Pr), 23 HIV-1-infected patients receiving sub-optimal therapy with dual nucleoside [nucleoside reverse transcriptase inhibitor (NRTI)] therapy but efficiently controlling viral replication (STP) and 19 antiretroviral therapy multi-experienced patients with actively replicating virus (MEP) were analysed. HIV-RNA was extracted from plasma samples, the Vpr region was amplified, cloned and sequenced. The Pol gene was amplified, directly sequenced and analysed using Sequence Navigator software.
Results: A significantly higher prevalence of the R77Q mutation was evidenced both in LTNP (86.7%) and STP (73.9%) in comparison with Pr (42.1%) and MEP (42.1%), (P = 0.007). Comparing groups of patients with progressive disease (Pr + MEP) and groups with non-progressive disease (LTNP + STP) the probability of harbouring the R77Q mutation was significantly higher in non-progressors (odds ratio, 5.16; P = 0.001).
Conclusions: Our results support the hypothesis of the association of R77Q mutation in the Vpr gene with delayed progression of HIV-1 disease. R77Q does not seem to be linked to a particular viral strain but might be associated to immunologic selection. The R77Q mutation might reduce CD4+ T-cell depletion possibly affecting T-cell survival in vivo by altering the pro-apoptotic activity of Vpr.
HIV-1 infection is characterized by progressive depletion of CD4+ T lymphocytes and immune deficiency. The number of circulating CD4+ T lymphocytes is inversely correlated with the level of viral replication, and persistent high viral loads in plasma predict a rapid disease onset . On the other hand, patients with low or undetectable plasma viraemia exhibit a non-progressive infection .
The progression time from infection with HIV-1 to the development of AIDS is known to be extremely variable. Moreover, a small proportion of HIV-1-infected persons, called long-term non-progressors (LTNP), remain AIDS-free and clinically healthy with relatively normal immunologic function many years after HIV-1 infection .
CD4+ T-cell depletion is mediated by both direct cytopathic viral effects and by apoptosis of uninfected cells [3–6].
Several HIV-1 proteins interact with the cellular regulatory pathways and have a direct impact on the survival of both infected and uninfected cells. Apoptotic and anti-apoptotic effects in vitro have been described for viral proteins such as Env, Tat, Nef and Vpr .
Several factors have been implicated in the lack of disease progression, including genetic, immunologic and virologic characteristics. There is evidence that viral strains in some LTNP may be attenuated and also accessory genes are defective in certain LTNP [8,9].
HIV-1 viral protein R (Vpr) is a 96-amino-acid accessory protein that is expressed late during viral replication . Vpr has pleiotropic effects on viral replication and cellular proliferation, differentiation, cytokine production, nuclear factor κB-mediated transcription and apoptosis [11–14]. During the early phase of the HIV-1 life cycle, Vpr facilitates the nuclear transport of the HIV-1 pre-integration complex across the limiting nuclear pore [15–18]. Moreover, Vpr is able to prevent host cell proliferation by arresting cell division in the G2 phase of the cell cycle [19–23]. This arrest has been shown to increase viral expression in dividing T cells as well as in macrophages [21,24,25].
Vpr is abundant in virions [11,26,27], is detectable in the serum of HIV-1- infected patients, and correlates with the viral load , in addition it is found in the nuclear and membrane fractions  and it can cross the plasma membrane [30–32], and finally it can localize to mitochondria to kill cells by apoptosis [30,32–35].
Lum and colleagues demonstrated that 80% of LTNP present a point mutation in Vpr at position 77 that leads to the substitution of arginine (R) with glutamine (Q); this mutation is far less frequent among patients with progressive disease .
A recent report analysed proviral DNA extracted from peripheral blood mononuclear cells (PBMC) and showed that the Vpr R77Q mutation is equally present in LTNP (four of 11) and in a group of slow-progressors (three of seven) .
The aim of this study was to analyse the prevalence of the R77Q mutation in four groups of HIV-1-infected patients: LTNP; sub-optimal treated patients (STP); patients who were naive to antiretroviral treatment with progressive disease (Pr) and patients with viral rebound after treatment failure (MEP).
Patients and methods
We randomly selected and examined 19 antiretroviral therapy (ART)-naive HIV-1- infected individuals with progressive disease (Pr, progressors), 15 LTNP defined as patients with an infection dating more than 10 years, a CD4+ T-cell count nadir higher than 500/μl and a low or undetectable viral load, 19 patients with detectable viral load failing antiretroviral therapy (MEP) and finally 23 HIV-1+ sub-optimal-treated patients (STP) defined as patients who had a CD4 cell count greater than 300/μl and HIV-RNA < 10 000 copies/ml at time of blood sampling. STP patients had been on dual therapy for a long period of time for personal or compliance reasons or for liver related toxicity. Written informed consent was obtained from all the patients before blood drawing and laboratory analysis.
Viral RNA isolation and reverse transcription
HIV-1 RNA was extracted from 0.5–1.0 ml of blood plasma using the Nuclisens Extraction Kit (BioMérieux bv, Boxtel, The Netherlands). One-quarter of the isolated viral RNA was reverse transcribed using AMV reverse transcriptase (Finnzymes Oy, Espoo, Finland), VprI R primer (5′-ATGTAATGCAACCT-3′) for the Vpr gene and P8 primer (5′-TAAATCTGACTTGCCCAATTCAATTTT-3′) for the Pol gene. The reaction was first activated at 70°C for 10 min, then incubated at 42°C for 60 min and heat inactivated for 5 min at 95°C.
The Pol gene was amplified with a nested polymerase chain reaction (PCR): in the first step we used 10 μl of cDNA product with P7 (5′-AGACCAGAGCCAACAGCCCCA-3′) and P8 primers. The reaction conditions were one cycle at 95°C for 9 min; 35 cycles at 94°C for 30 s, at 62°C for 1 min and at 72°C for 2 min; and an extension cycle at 72°C for 6 min. Twenty microlitres of the first step product (1218 bp) were added to the second step mix to amplify two distinct Pol regions codifying HIV-1 reverse transcriptase. The first region was amplified using primers no. 3 (5′-TGTAAAACGACGGCCAGTGTATTAGTAGGACCTACACCT-3′) and SEQ1 (5′-CAGGAAACAGCTATGACCGCACGATATCTAATCCTGGTGTCTCA-3′), while the second region was amplified using primers PIA3 (5′-TGTAAAACGACGGCCAGTATTTTTCAGTTCCCTTAG-3′) and no. 4 (5′-CAGGAAACAGCTATGACCTCAGTCCAGCTGTCTTTTTCTGGC-3′). Reaction conditions were one cycle at 95°C for 9 min; 2 cycles at 98°C for 50 s, at 45°C for 50 s and at 72°C for 2 min; followed by 38 cycles at 94°C for 30 s, at 55°C for 50 s and at 72°C for 2 min; and an extension cycle at 72°C for 10 min. The secondary PCR products (511 bp for the first region and 418 bp for the second) were purified using the QIAquick PCR purification kit (QIAGEN, Toronto, Ontario, Canada) and directly sequenced with the PRISM Big Dye Terminator cycle sequencing kit and an ABI 3100 automatic sequencer (Applied Biosystems, Inc, Foster City, California, USA). Sequences were analysed using Sequence Navigator software (Applied Biosystems, Inc.).
The Vpr region was amplified with nested PCR: in the first step we used one-sixth of the cDNA product with VprI F (5′-GAGACTGGCATTTGGGTCA-3′) and VprI R primers. The reaction conditions were one cycle at 50°C for 30 min; one cycle at 95°C for 15 min; 30 cycles at 95°C for 1 min, at 50°C for 1 min and at 72°C for 1.5 min; and an extension cycle at 70°C for 7 min. Three microlitres of the first step product (800 bp) were added to the second step mix with primers VprII F (5′-GCAGGACATAACAAGGTAGGA-3′) and VprII R (5′-GAAGCGGAGACAGCGAC-3′). Reaction conditions were one cycle at 95°C for 15 min; 30 cycles at 95°C for 1 min, at 50°C for 1 min and at 72°C for 1.5 min; and an extension cycle at 70°C for 10 min. The secondary PCR product (547 bp) was purified using the QIAquick PCR Purification kit (QIAGEN) and cloned into the pGEM-T Easy vector (Promega, Madison, Wisconsin, USA). Blue-white screening identified recombinant clones and 10 clones per patient were sequenced as described above for Pol sequencing.
Vpr Phylogenetic analysis
Cycle-sequencing dideoxychain termination chemistry with sequence-specific primers was used to obtain an approximately 290 bp sequence on an ABI 3100 automated sequencer.
The raw nucleic acid sequences were edited, assembled to generate the consensus sequences and trimmed to equivalent length (265 bp) using the Sequence Navigator program. The 78 sequences were aligned with 90 Vpr representative sequences available in the Los Alamos database (http://hiv-web.lan1.gov) using the CLUSTAL algorithm implemented in BioEdit version 5.0.9 (http://www.mbio.ncsu.edu/BioEdit/page2.html). From two to five strains were chosen as representative of each of the nine pure subtypes (A–D, F–H, J and K), the five sub-subtypes (A1, A2, A3, and F1 and F2) and the 16 known circulating recombinant forms (CRFs).
Subtype or CRF assignment was performed using the PHYLIP software package, version 3.57 (http://evolution.genetics.washington.edu/phylip.html) . Evolutionary distances were estimated using DNADIST with the Kimura two-parameter method and a transition/transversion ratio of 2.0. Phylogenetic relationships were inferred using neighbour-joining method. Reproducibility of branching patterns was evaluated with SEQBOOT (bootstrap method; 1000 replicates), and the consensus tree was generated with CONSENSE.
Comparisons between categorical (group, sex) variables were assessed by means of chi-squared and Fisher exact tests. Continuous variables (viral load and CD4 cell count) were analysed utilizing analyses of variance (ANOVA) models; in case of non-normal distribution of variables (HIV-RNA), Kruskal–Wallis non-parametric test was performed. Multivariate relative risks for potential predictors of presenting R77Q mutation were estimated using a logistic regression model; 95% confidence intervals (CI) for each estimated risk were calculated from standard errors. All tests were two-tailed and performed at the conventional level of statistical significance of 0.05.
The general characteristics of the patients enrolled in the study are summarized in Table 1. No statistically significant difference emerged among the studied groups with respect to sex. As expected, patients in the Pr group were younger (P = 0.032 by ANOVA) and had a shorter time of infection (P < 0.001). The LTNP had higher CD4+ T-cell count (P = 0.001). Subjects in the MEP group showed the highest HIV-RNA viraemia (P = 0.001).
Patients on sub-optimal therapy were on the following antiretroviral combinations: stavudine + lamivudine, stavudine + didanosine, zidovudine + lamivudine, zidovudine + didanosine, zidovudine + zalcitabine. These patients had been on a dual NRTI therapy for at least 6 years with a median time on therapy of 8.1 years.
MEP were patients failing highly active antiretroviral therapy (HAART) with detectable viral load and receiving several different combination of drugs; these patients were analysed as a control group of STP considering the similar pattern of genotypic resistance in the Pol region.
Drug-related genotypic mutation in RT HIV-1 RNA
Due to low levels of plasma viraemia, only 14 of 23 STP could be sequenced for RT HIV-1 regions. All the subjects exhibited a certain degree of genotypic resistance to NRTI.
Eleven of 14 subjects treated with zidovudine or stavudine presented a variable number of thymidine analogue mutations (TAMs). Moreover, all sequences obtained from patients treated with lamivudine showed the M184V mutation (12 of 14). Of note, the virus from a single patient remained completely wild type in the RT region. Neither K65R mutation nor 69 insertion nor Q151M complex emerged; furthermore no evidence of mutations conferring a multi-drug resistance profile towards the NRTI was present in this group of patients.
Genotypic changes were evidenced in 18 of 19 patients who failed antiretroviral therapy (MEP). All 18 patients presented amino acid substitutions that conferred resistance to one or more compounds. Sixteen of 18 patients had been treated with lamivudine and showed the M184I/V mutation. Seven subjects presented the TAM-1 profile; namely mutations at codons 41+210+215 (a troublesome NRTI resistance feature), and five subjects featured the TAM-2 profile; namely mutations at codons 67+70+219. Of note, no patient presented both profiles at the same time and no K65R mutation occurred. Q151M was evidenced in one subject together with mutations at codons 69 and 116. Eight of 18 subjects presented various degrees of non-nucleoside reverse transcriptase inhibitor resistance, the most frequent mutations being at codons 103, 181 and 190, thus confirming the persistence of these mutations over time.
Comparison of the frequency of the R77Q mutation in LTNP, Pr, STP and MEP
The sequence analysis of Vpr showed a significantly higher prevalence of the R77Q mutation both in LTNP (86.7%) and STP (73.9%) in comparison with Pr (42.1%) and MEP (42.1%). The differences were statistically significant among the different groups (P = 0.007, by ANOVA). Direct comparison of the Vpr sequence in 19 progressors and in 15 LTNP showed that eight progressors had glutamine (Q) in position 77 (42.1%), whereas eight patients had arginine (R) (42.1%) and three patients had histidine (H) (15.8%); on the contrary, 13 LTNP had glutamine (86.7%), one LTNP had arginine (6.65%) and one LTNP had histidine (6.65%). Statistical analysis revealed significant differences in the frequency of the R77Q mutation in LTNP compared with progressors (P < 0.05), whereas there was no statistical relevance in the presence of R77H mutation in these two groups of patients (P = 0.41) (Fig. 1).
We compared the Vpr sequence of 19 progressors with 23 STP. Our analysis showed that 17 two-ART drug-treated patients had glutamine (73.9%), four had arginine (17.4%) and two had histidine (8.7%). Statistical analysis revealed significant differences in the frequency of the R77Q mutation in STP compared with progressors (P < 0.05), although there was no statistical relevance in the presence of R77H mutation in these two groups of patients (P = 0.48) (Fig. 2).
Equation (Uncited)Image Tools
The prevalence of the mutation at position 77 in patients with a controlled infection despite sub-optimal therapy (STP) was also analysed in comparison with patients with treatment failure during HAART (MEP). In the second group glutamine was represented in eight (42.1%), arginine in 10 (52.6%) and histidine in one patient (5.3%). Statistical analysis revealed significant differences in the frequency of the R77Q mutation in STP in comparison with MEP (P < 0.05), whereas there was no statistical relevance in the presence of the R77H mutation in these two different groups of patients (P = 0.67) (Fig. 3).
No correlation was observed between particular RT mutations and Vpr 77 mutation either in STP or in MEP.
Moreover, when comparing groups of patients with progressive disease (Pr + MEP) and groups with non-progressive disease (LTNP + STP) the probability of harbouring the R77Q mutation was significantly higher in non-progressors (odds ratio, 5.16; 95% CI, 1.88–14.18; P = 0.001).
Equation (Uncited)Image Tools
Vpr Phylogenetic analysis
Phylogenetic analysis revealed that all but five sequences clustered into subtype B with bootstrap values higher than 80%. The non-B isolates were significantly related with reference strains of sub-subtypes A3, F1 and CRF02_AG in one, two and two cases, respectively.
Equation (Uncited)Image Tools
A unique group of HIV-1-infected individuals remain clinically healthy and do not experience a decline in CD4+ T-cell counts. A recent report has shown that a point mutation, involving the substitution from arginine to glutamine at position 77 in the Vpr gene, affects viral pathogenesis and is involved in the mechanism of long-term non-progression of HIV-1 infection. Similarly to our results, they found that 80% of LTNP had the mutation, whereas only 33% of progressors presented the R77Q .
On the contrary another study did not confirm a correlation between the frequency of the R77Q substitution and different measures of disease intensity .
We analysed the cohort of LTNP enrolled in the Resistant Host Prospective Study (rHoPeS) in Italy and our data support the relevance of the point mutation in preventing disease progression as 86.7% of LTNP bear the substitution compared with only 42.1% of progressors. Both our analysis and the study by Lum et al were performed on HIV-RNA, while the study failing to detect the relevance of the mutation in altering disease progression was done only on HIV-DNA from PBMC.
It is possible that the different results of the studies are related to the different technical approach. HIV-RNA reflects the viral strain currently proliferating and affecting CD4+ T-cell depletion, whereas integrated DNA is not the main replicating strain and represents the archived virus.
As demonstrated for antiretroviral therapy-induced mutations in the Pol gene, HIV mutations in PBMC may persist for a long time, possibly lifelong and re-emerge in the absence of selective pressure [40,41].
Different viral quasispecies variations in the Vpr gene may exist within a single person and it is possible that an epitope-specific immune response is able to maintain the replicating virus in a less cytopathic asset blocking the replication of more aggressive strains that may be archived in PBMC. Moreover other studies have related the C-terminus region of Vpr to disease progression [42,43].
We also analysed the frequency of the Vpr mutation in a peculiar group of patients that, despite dual NRTI therapy, are able to control HIV-1 replication and maintain a stable CD4+ T-cell count for a long period of time and compared them to patients failing antiretroviral therapy and showing a progressive depletion of CD4+ T cells (MEP).
STP patients display a high percentage of R77Q mutation similar to LTNP and significantly higher than progressors and MEP.
The C-terminal region of Vpr induces apoptosis by binding to the adenine nucleotide translocator (ANT) component of the mitochondrial permeability transition pore complex . Mitochondrial membrane permeabilization (MMP) is a key event of apoptotic cell death [45–51]. The MMP-inducing activity of Vpr resides in its COOH-terminal moiety (Vpr 52-96), within an α-helical motif of 12 amino acids (Vpr 71–82) containing several critical arginine (R) residues (R73, R77, R80) strongly conserved among different pathogenic HIV-1 isolates [32–34]. These residues participate in the physical interaction with the first loop of ANT exposed to the mitochondrial intermembrane space. This complex forms a composite ion channel, which dissipates the ΔΨm and thus favors MMP and subsequent apoptosis . The interaction of Vpr with ANT is abrogated by the R77Q mutation and such mutation impairs Vpr capability to induce apoptosis of T lymphocytes .
Among patients in sub-optimal therapy not only patients with viraemia < 50 copies/ml but also patients with persistent low levels of viral replication do not experience CD4+ T-cell depletion confirming a potential role for the Vpr R77Q mutation in impeding CD4+ T-cell apoptosis.
It is noteworthy that the large majority of patients with dual NRTI therapy also present the mutation M184V that has been associated to reduction of viral fitness [52–54]. Thus the co-existence with the R77Q mutation in the Vpr gene might further contribute to allow a long-term control of HIV-1 infection in STP. This is not the case in MEP, further suggesting the potential contribution of a specific immune response to Vpr.
A recent report observed a significantly higher prevalence of the R77Q mutation in subtype A than in subtype B viruses (84 versus 32%) ; our data based mainly on subtype B in all the different groups of patients confirm a similar frequency in patients with progressive disease (42.1%), but a much higher frequency in LTNP (86.7%).
The standard of care of HIV-1 treatment consists of continuous HAART, the criteria for initiation of therapy are not univocal, therefore the identification of a laboratory parameter such as the R77Q Vpr point mutation able to predict disease progression might help addressing such issues in conjunction with CD4+ T-cell count and HIV-RNA.
Clinicians are currently facing the problem of drug toxicity, lack of adherence to therapy and the requests of patients to interrupt therapy. Therefore, treatment interruptions are entering clinical practice, but clear criteria for interruption, monitoring and re-introduction of therapy are not available. Treatment interruptions expose patients to the risk of brisk CD4+ T-cell decline and disease progression, but allow reduction in drug toxicities and preservation of future treatment options. Monitoring the R77Q Vpr mutation might constitute a parameter to stop therapy and decide re-initiation of treatment; clinical trials to evaluate the clinical predictive role of such mutation are to be considered.
We are grateful to Bianca Ghisi for excellent editorial assistance, to all the patients participating in the study and to the staff at the Institute of Infectious Diseases and Tropical Medicine, ‘L. Sacco’ Hospital, who cared for the patients.
Sponsorship: This study was supported in part by E.L.V.I.S. (Evaluation of Long Term Non-Progressors Viro-Immunological Italian Studies) with the grants 40F39, 30C32 and 30D34 from the Istituto Superiore di Sanità, Italy.
1. Mellors JW, Munoz A, Giorgi JV, Margolick JB, Tassoni CJ, Gupta P, et al
. Plasma viral load and CD4+ lymphocytes as prognostic markers of HIV-1 infection. Ann Intern Med 1997; 126:946–954.
2. Buchbinder S, Vittinghoff E. HIV-infected long-term nonprogressors: epidemiology, mechanisms of delayed progression, and clinical and research implications. Microbes Infect 1999; 13:1113–1120.
3. Cao J, Park IW, Cooper A, Sodroski J. Molecular determinants of acute single-cell lysis by human immunodeficiency virus type 1. J Virol 1996; 70:1340–1354.
4. LaBonte JA, Patel T, Hofmann W, Sodroski J. Importance of membrane fusion mediated by human immunodeficiency virus envelope glycoproteins for lysis of primary CD4-positive T cells. J Virol 2000; 74:10690–10698.
5. Lifson JD, Feinberg MD, Reynes GR, Rabin L, Banapour B, Chakrabarti BS, et al
. Induction of CD4-dependent cell fusion by the HTLV-III/LAV envelope glycoprotein. Nature 1986; 323:725–728.
6. Roshal M, Zhu Y, Planelles V. Apoptosis in AIDS. Apoptosis 2001; 6:103–116.
7. Xu XN, Laffert B, Screaton GR, Kraft M, Wolf D, Kolanus W, et al
. Induction of Fas ligand expression by HIV involves the interaction of Nef with the T cell receptor zeta chain. J Exp Med 1999; 189:1489–1496.
8. Connor RI, Sheridan KE, Lai C, Zhang L, Ho DD. Characterization of the functional properties of env genes from long-term survivors of human immunodeficiency virus type 1 infection. J Virol 1996; 70:5306–5311.
9. Michael NL, Chang G, d'Arcy LA, Ehrenberg PK, Mariani R, Busch MP, et al
. Defective accessory genes in a human immunodeficiency virus type 1-infected long-term survivor lacking recoverable virus. J Virol 1995; 69:4228–4236.
10. Morellet N, Bouaziz S, Petitjean P, Roques BP. NMR structure of the HIV-1 regulatory protein VPR. J Mol Biol 2003; 327:215–227.
11. Emerman M, Malim MH. HIV-1 regulatory/accessory genes: keys to unraveling viral and host cell biology. Science 1998; 280:1880–1884.
12. Frankel AD, Young JAT. HIV-1: fifteen proteins and an RNA. Annu Rev Biochem 1998; 67:1–25.
13. Bukrinsky M, Adzhubei A. Viral protein R of HIV-1. Rev Med Virol 1999; 9:39–49.
14. Stewart SA, Poon B, Song JY, Chen ISY. Human immunodeficiency virus type 1 vpr induces apoptosis through caspase activation. J Virol 2000; 74:3105–3111.
15. Connor RI, Chen BK, Choe S, Landau NR. Vpr is required for efficient replication of human immunodeficiency virus type-1 in mononuclear phagocytes. Virology 1995; 206:935–944.
16. Heinzinger NK, Bukinsky MI, Haggerty SA, Ragland AM, Kewalramani V, Lee MA, et al
. The Vpr protein of human immunodeficiency virus type 1 influences nuclear localization of viral nucleic acids in nondividing host cells. Proc Natl Acad Sci USA 1994; 91:7311–7315.
17. Popov S, Rexach M, Zybarth G, Reiling N, Lee MA, Ratner L, et al
. Viral protein R regulates nuclear import of the HIV-1 pre-integration complex. EMBO J 1998; 17:909–917.
18. Bukrinsky MI, Sharova N, Dempsey MP, Stanwick TL, Bukrinskaya AG, Haggerty S, et al
. Active nuclear import of human immunodeficiency virus type 1 preintegration complexes. Proc Natl Acad Sci USA 1992; 89:6580–6584.
19. Goh WC, Rogel ME, Kinsey CM, Michael SF, Fultz PN, Nowak MA, et al
. HIV-1 Vpr increases viral expression by manipulation of the cell cycle: a mechanism for selection of Vpr in vivo. Nature Med 1998; 4:65–71.
20. He J, Choe S, Walker R, Di Marzio P, Morgan DO, Landau NR. Human immunodeficiency virus type 1 viral protein R Vpr arrests cells in the G2 phase of the cell cycle by inhibiting p34cdc2 activity. J Virol 1995; 69:6705–6711.
21. Jowett JB, Planelles V, Poon B, Shah NP, Chen ML, Chen IS. The human immunodeficiency virus type 1 vpr gene arrests infected T cells in the G2 + M phase of the cell cycle. J Virol 1995; 69:6304–6313.
22. Re F, Braaten D, Franke EK, Luban J. Human immunodeficiency virus type 1 Vpr arrests the cell cycle in G2 by inhibiting the activation of p34cdc2-cyclin B. J Virol 1995; 69:6859–6864.
23. Rogel ME, Wu LI, Emerman M. The human immunodeficiency virus type 1 vpr gene prevents cell proliferation during chronic infection. J Virol 1995; 69:882–888.
24. Fouchier RA, Malim MH. Nuclear import of human immunodeficiency virus type-1 preintegration complexes. Advan Virus Res 1999; 52:275–299.
25. Subbramanian RA, Kessous-Elbaz A, Lodge R, Forget J, Yao XJ, Bergeron D, et al
. Human immunodeficiency virus type 1 Vpr is a positive regulator of viral transcription and infectivity in primary human macrophages. J Exptl Med 1998; 187:1103–1111.
26. Cullen BR. HIV-1 auxiliary proteins: making connections in a dying cell. Cell 1998; 93:685–692.
27. Singh SP, Lai D, Cartas M, Serio D, Murali R, Kalyanaraman VS, et al
. Epitope-tagging approach to determine the stoichiometry of the structural and nonstructural proteins in the virus particles: amount of Vpr in relation to Gag in HIV-1. Virology 2000; 268:364–371.
28. Levy DN, Refaeli Y, MacGregor BR, Weiner DB. Serum Vpr regulates productive infection and latency of human immunodeficiency virus type 1. Proc Natl Acad Sci USA 1994; 91:10873–10877.
29. Lu YL, Spearman P, Ratner L. Human immunodeficiency virus type 1 viral protein R localization in infected cells and virions. J Virol 1993; 67:6542–6550.
30. Arunagiri C, Macreadie I, Hewhish D, Azadi A. A C-terminal domain of HIV-1 accessory protein Vpr is involved in penetration, mitochondrial dysfunction and apoptosis of human CD4+ lymphocytes. Apoptosis 1997; 2:69–76.
31. Kichler A, Pages JC, Leborgne C, Druillenec S, Lenoir C, Coulaud D, et al
. Efficient DNA transfection mediated by the C-terminal domain of human immunodeficiency virus type 1 viral protein R. J Virol 2000; 74:5424–5431.
32. Jacotot E, Ravagnan L, Loeffler M, Ferri KF, Vieira HLA, Zamzami N, et al
. The HIV-1 viral protein R induces apoptosis via a direct effect on the mitochondrial permeability transition pore. J Exp Med 2000; 191:33–45.
33. Macreadie IG, Castelli LA, Hewish DR, Kirkpatrick A, Ward AC, Azad AA. A domain of human immunodeficiency virus type 1 Vpr containing repeated H S/F RIG amino acid motifs causes cell growth arrest and structural defects. Proc Natl Acad Sci USA 1995; 92:2770–2774.
34. Macreadie IG, Thorburn DR, Kirby DM, Castelli LA, Derozario NL, Azad AA. HIV-1 protein Vpr causes gross mitochondrial dysfunction in the yeast Saccharomyces cerevisiae
. FEBS Lett 1997; 410:145–149.
35. Muthumani K, Montaner LJ, Ayyavoo V, Weine DB. Vpr-GFP virion particle identifies HIV-infected targets and preserves HIV-1Vpr function in macrophages and T-cells. DNA Cell Biol 2000; 19:179–188.
36. Lum JJ, Cohen OJ, Nie Z, Weaver JG, Gomez T, Yao XJ, et al
. Vpr R77Q is associated with long-term nonprogressive HIV infection and impaired induction of apoptosis. J Clin Invest 2003; 111:1547–1554.
37. Rodés B, Toro C, Paxinos E, Poveda E, Martinez-Padial M, Benito JM, et al
. Differences in disease progression in a cohort of long-term non-progressors after more than 16 years of HIV-1 infection. AIDS 2004; 18:1109–1116.
38. Felsenstein J. PHYLIP: Phylogeny Inference Package
, version 3.52. Seattle, WA: University of Washington; 1996.
39. Cavert W, Webb CH, Balfour HH Jr. Alterations in the C-terminal region of the HIV-1 accessory gene vpr do not confer clinical advantage to subjects receiving nucleoside antiretroviral therapy. J Infect Dis 2004; 189:2181–2184.
40. Ghosn J, Viard JP, Katlama C, de Almeida M, Tubiana R, Letourneur F, et al
. Evidence of genotypic resistance diversity of archived and circulating viral strains in blood and semen of pre-treated HIV-infected men. AIDS 2004; 18:447–457.
41. Delaugerre C, Morand-Joubert L, Chaix ML, Picard O, Marcelin AG, Schneider V, et al
. Persistence of multidrug-resistant HIV-1 without antiretroviral treatment 2 years after sexual transmission. Antivir Ther 2004; 9:415–421.
42. Wang B, Ge YC, Palasanthiran P, Xiang SH, Ziegler J, Dwyer DE, et al
. Gene defects clustered at the C-terminus of the vpr gene of HIV-1 in long-term nonprogressing mother and child pair: in vivo evolution of vpr quasispecies in blood and plasma. Virology 1996; 223:224–232.
43. Somasundaran M, Sharkey M, Brichacek B, Luzuriaga K, Emerman M, Sullivan JL, et al
. Evidence for a cytopathogenicity determinant in HIV-1 Vpr. Proc Natl Acad Sci USA 2002; 99:9503–9508.
44. Jacotot E, Ferri KF, El Hamel C, Brenner C, Druillennec S, Hoebeke J, et al
. Control of mitochondrial membrane permeabilization by adenine nucleotide translocator interacting with HIV-1 viral protein R and Bcl-2. J Exp Med 2001; 193:509–520.
45. Kroemer G, Zamzami N, Susin SA. Mitochondrial control of apoptosis. Immunol Today 1997; 18:44–51.
46. Green DR, Reed JC. Mitochondria and apoptosis. Science 1998; 281:1309–1312.
47. Lemasters JJ, Nieminen AL, Qjan T, Trost LC, Elmore SP, Nishimura Y, et al
. The mitochondrial permeability transition in cell death: a common mechanism in necrosis, apoptosis and autophagy. Biochim Biophys Acta 1998; 1366:177–196.
48. Wallace DC. Mitochondrial diseases in man and mouse. Science 1999; 283:1482–1488.
49. Vander Heiden MG, Thompson CB. Bcl-2 proteins: regulators of apoptosis or of mitochondrial homeostasis? Nat Cell Biol 1999; 1:E209–E216.
50. Gross A, McDonnell JM, Korsmeyer SJ. BCL-2 family members and the mitochondria in apoptosis. Genes Dev 1999; 13:1899–1911.
51. Kroemer G, Reed JC. Mitochondrial control of cell death. Nat Med 2000; 6:513–519.
52. Wainberg MA, Drosopoulos WC, Salomon H, Hsu M, Borkow G, Parniak M, et al
. Enhanced fidelity of 3TC-selected mutant HIV-1 reverse transcriptase. Science 1996; 271:1282–1285.
53. Wei X, Liang C, Gotte M, Wainberg MA. The M184V mutation in HIV-1 reverse transcriptase reduces the restoration of wild-type replication by attenuated viruses. AIDS 2002; 16:2391–2398.
54. Wei X, Liang C, Gotte M, Wainberg MA. Negative effect of the M184V mutation in HIV-1 reverse transcriptase on initiation of viral DNA synthesis. Virology 2003; 311:202–212.
55. Fischer A, Lejczak C, Lambert C, Roman F, Servais J, Karita E, et al
. Is the Vpr R77Q mutation associated with long-term non-progression of HIV infection? AIDS 2004; 18:1346–1347.
The Resistant Host Prospective Study (rHoPeS) participants are: F. Adorni, B. Allegranza, G.P. Cadeo, G.P. Carosi, M.C. Colombo, E. Concia, G. Cristini, G. Di Perri, M. Galli, E. Gianelli, L. Meroni, G. Migliorino, G. Monolo, S. Pasquinucci, E. Raise, C. Riva, S. Santambrogio, M. Sciandra, A. Sinicco, M.G. Suardi, F. Suter, R. Tambini, M. Violin, A. Valenza.
This article has been cited 18 time(s).
VirologyElevated hypermutation levels in HIV-1 natural viral suppressorsVirology
Journal of Medical VirologyMutations in the nef and vif genes associated with progression to AIDS in elite controller and slow-progressor PatientsJournal of Medical Virology
AIDS Research and Human RetrovirusesMolecular characterization of the HIV type 1 vpr gene in infected chinese former blood/plasma donors at different stages of diseasesAIDS Research and Human Retroviruses
Plos OneCharacterization of the Molecular Determinants of Primary HIV-1 Vpr Proteins: Impact of the Q65R and R77Q Substitutions on Vpr FunctionsPlos One
Current Hiv Research
Structure-Function Relationship of Vpr: Biological Implications
Current Hiv Research, 7(2):
AIDS Research and Human RetrovirusesViral Genetic Determinants of Nonprogressive HIV Type 1 Subtype C Infection in Antiretroviral Drug-Naive ChildrenAIDS Research and Human Retroviruses
Biochemical and Biophysical Research CommunicationsCell-based chemical genetic screen identifies damnacanthal as an inhibitor of HIV-1 Vpr induced cell deathBiochemical and Biophysical Research Communications
AIDS Research and Human RetrovirusesGenetic and biological characterization of recombinant HIV type 1 with Env derived from long-term nonprogressor (LTNP) virusesAIDS Research and Human Retroviruses
Journal of VirologyProtein Kinase A Phosphorylation Activates Vpr-Induced Cell Cycle Arrest during Human Immunodeficiency Virus Type 1 InfectionJournal of Virology
AIDS Research and Human RetrovirusesGenetic changes associated with distinct patterns of HIV type 1 persistence in chronically infected cell linesAIDS Research and Human Retroviruses
AIDS Research and Human RetrovirusesVpr in plasma of HIV type 1-positive patients is correlated with the HIV type 1 RNA titersAIDS Research and Human Retroviruses
Plos OneThe Immunosuppressive Properties of the HIV Vpr Protein Are Linked to a Single Highly Conserved Residue, R90Plos One
Journal of VirologyGenetic characterization of human immunodeficiency virus type 1 in elite controllers: Lack of gross genetic defects or common amino acid changesJournal of Virology
Current Hiv Research
The presence of antibodies recognizing a peptide derived from the second conserved region of HIV-1 gp120 correlates with non-progressive HIV infection
Current Hiv Research, 5(5):
Journal of Immunology
Tat-Induced FOXO3a Is a Key Mediator of Apoptosis in HIV-1-Infected Human CD4(+) T Lymphocytes
Journal of Immunology, 181():
Early restoration of mucosal CD4 memory CCR5 T cells in the gut of SIV-infected rhesus predicts long term non-progression
long-term non-progressors; vpr; disease progression; antiretroviral therapy; resistance genotyping; HIV phylogenesis
© 2006 Lippincott Williams & Wilkins, Inc.
What does "Remember me" mean?
By checking this box, you'll stay logged in until you logout. You'll get easier access to your articles, collections,
media, and all your other content, even if you close your browser or shut down your
To protect your most sensitive data and activities (like changing your password),
we'll ask you to re-enter your password when you access these services.
What if I'm on a computer that I share with others?
If you're using a public computer or you share this computer with others, we recommend
that you uncheck the "Remember me" box.
Highlight selected keywords in the article text.
Data is temporarily unavailable. Please try again soon.