scholarly journals A Riboswitch Regulates RNA Dimerization and Packaging in Human Immunodeficiency Virus Type 1 Virions

2004 ◽  
Vol 78 (19) ◽  
pp. 10814-10819 ◽  
Author(s):  
Marcel Ooms ◽  
Hendrik Huthoff ◽  
Rodney Russell ◽  
Chen Liang ◽  
Ben Berkhout

ABSTRACT The genome of retroviruses, including human immunodeficiency virus type 1 (HIV-1), consists of two identical RNA strands that are packaged as noncovalently linked dimers. The core packaging and dimerization signals are located in the downstream part of the untranslated leader of HIV-1 RNA—the Ψ and the dimerization initiation site (DIS) hairpins. The HIV-1 leader can adopt two alternative conformations that differ in the presentation of the DIS hairpin and consequently in their ability to dimerize in vitro. The branched multiple-hairpin (BMH) structure folds the poly(A) and DIS hairpins, but these domains are base paired in a long distance interaction (LDI) in the most stable LDI conformation. This LDI-BMH riboswitch regulates RNA dimerization in vitro. It was recently shown that the Ψ hairpin structure is also presented differently in the LDI and BMH structures. Several detailed in vivo studies have indicated that sequences throughout the leader RNA contribute to RNA packaging, but how these diverse mutations affect the packaging mechanism is not known. We reasoned that these effects may be due to a change in the LDI-BMH equilibrium, and we therefore reanalyzed the structural effects of a large set of leader RNA mutations that were presented in three previous studies (J. L. Clever, D. Mirandar, Jr., and T. G. Parslow, J. Virol. 76:12381-12387, 2002; C. Helga-Maria, M. L. Hammarskjold, and D. Rekosh, J. Virol. 73:4127-4135, 1999; R. S. Russell, J. Hu, V. Beriault, A. J. Mouland, M. Laughrea, L. Kleiman, M. A. Wainberg, and C. Liang, J. Virol. 77:84-96, 2003). This analysis revealed a strict correlation between the status of the LDI-BMH equilibrium and RNA packaging. Furthermore, a correlation is apparent between RNA dimerization and RNA packaging, and these processes may be coordinated by the same LDI-BMH riboswitch mechanism.

1998 ◽  
Vol 72 (5) ◽  
pp. 3991-3998 ◽  
Author(s):  
Daniel C. St. Louis ◽  
Deanna Gotte ◽  
Eric Sanders-Buell ◽  
David W. Ritchey ◽  
Mika O. Salminen ◽  
...  

ABSTRACT Recombinant forms of human immunodeficiency virus type 1 (HIV-1) have been shown to be of major importance in the global AIDS pandemic. Viral RNA dimer formation mediated by the dimerization initiation sequence (DIS) is believed to be essential for viral genomic RNA packaging and therefore for RNA recombination. Here, we demonstrate that HIV-1 recombination and replication are not restricted by variant DIS loop sequences. Three DIS loop forms found among HIV-1 isolates, DIS (CG), DIS (TA), and DIS (TG), when introduced into deletion mutants of HIV-1 recombined efficiently, and the progeny virions replicated with comparable kinetics. A fourth DIS loop form, containing an artificial AAAAAA sequence disrupting the putative DIS loop-loop interactions [DIS (A6)], supported efficient recombination with DIS loop variants; however, DIS (A6) progeny virions exhibited a modest replication disadvantage in mixed cultures. Our studies indicate that the nonhomologous DIS sequences found in different HIV-1 subtypes are not a primary obstacle to intersubtype recombination.


2002 ◽  
Vol 76 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
Barbara Müller ◽  
Tilo Patschinsky ◽  
Hans-Georg Kräusslich

ABSTRACT The Gag-derived protein p6 of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in the release of virions from the membranes of infected cells. It is presumed that p6 and functionally related proteins from other viruses act as adapters, recruiting cellular factors to the budding site. This interaction is mediated by so-called late domains within the viral proteins. Previous studies had suggested that virus release from the plasma membrane shares elements with the cellular endocytosis machinery. Since protein phosphorylation is known to be a regulatory mechanism in these processes, we have investigated the phosphorylation of HIV-1 structural proteins. Here we show that p6 is the major phosphoprotein of HIV-1 particles. After metabolic labeling of infected cells with [ortho- 32P]phosphate, we found that phosphorylated p6 from infected cells and from virus particles consisted of several forms, suggesting differential phosphorylation at multiple sites. Apparently, phosphorylation occurred shortly before or after the release of p6 from Gag and involved only a minor fraction of the total virion-associated p6 molecules. Phosphoamino acid analysis indicated phosphorylation at Ser and Thr, as well as a trace of Tyr phosphorylation, supporting the conclusion that multiple phosphorylation events do occur. In vitro experiments using purified virus revealed that endogenous or exogenously added p6 was efficiently phosphorylated by virion-associated cellular kinase(s). Inhibition experiments suggested that a cyclin-dependent kinase or a related kinase, most likely ERK2, was involved in p6 phosphorylation by virion-associated enzymes.


2003 ◽  
Vol 77 (1) ◽  
pp. 291-300 ◽  
Author(s):  
L. Musey ◽  
Y. Ding ◽  
J. Cao ◽  
J. Lee ◽  
C. Galloway ◽  
...  

ABSTRACT Induction of adaptive immunity to human immunodeficiency virus type 1 (HIV-1) at the mucosal site of transmission is poorly understood but crucial in devising strategies to control and prevent infection. To gain further understanding of HIV-1-specific T-cell mucosal immunity, we established HIV-1-specific CD8+ cytotoxic T-lymphocyte (CTL) cell lines and clones from the blood, cervix, rectum, and semen of 12 HIV-1-infected individuals and compared their specificities, cytolytic function, and T-cell receptor (TCR) clonotypes. Blood and mucosal CD8+ CTL had common HIV-1 epitope specificities and major histocompatibility complex restriction patterns. Moreover, both systemic and mucosal CTL lysed targets with similar efficiency, primarily through the perforin-dependent pathway in in vitro studies. Sequence analysis of the TCRβ VDJ region revealed in some cases identical HIV-1-specific CTL clones in different compartments in the same HIV-1-infected individual. These results clearly establish that a subset of blood and mucosal HIV-1-specific CTL can have a common origin and can traffic between anatomically distinct compartments. Thus, these effectors can provide immune surveillance at the mucosa, where rapid responses are needed to contain HIV-1 infection.


1998 ◽  
Vol 72 (11) ◽  
pp. 9337-9344 ◽  
Author(s):  
Yi-jun Zhang ◽  
Tatjana Dragic ◽  
Yunzhen Cao ◽  
Leondios Kostrikis ◽  
Douglas S. Kwon ◽  
...  

ABSTRACT We have tested a panel of pediatric and adult human immunodeficiency virus type 1 (HIV-1) primary isolates for the ability to employ the following proteins as coreceptors during viral entry: CCR1, CCR2b, CCR3, CCR4, CCR5, CCR8, CXCR4, Bonzo, BOB, GPR1, V28, US28, and APJ. Most non-syncytium-inducing isolates could utilize only CCR5. All syncytium-inducing viruses used CXCR4, some also employed V28, and one (DH123) used CCR8 and APJ as well. A longitudinal series of HIV-1 subtype B isolates from an infected infant and its mother utilized Bonzo efficiently, as well as CCR5. The maternal isolates, which were syncytium inducing, also used CXCR4, CCR8, V28, and APJ.


1998 ◽  
Vol 9 (5) ◽  
pp. 412-421 ◽  
Author(s):  
C Chamorro ◽  
M-J Camarasa ◽  
M-J Pérez-Pérez ◽  
E de Clercq ◽  
J Balzarini ◽  
...  

Novel derivatives of the potent human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitor TSAO-T have been designed, synthesized and tested for their in vitro antiretro-viral activity against HIV. These TSAO-T derivatives have been designed as potential bidentate inhibitors of HIV-1 RT, which combine in their structure the functionality of a non-nucleoside RT inhibitor (TSAO-T) and a bivalent ion-chelating moiety (a β-diketone moiety) linked through an appropriate spacer to the N-3 of thymine of TSAO-T . Some of the new compounds have an anti-HIV-1 activity comparable to that of the parent compound TSAO-T, but display a markedly increased antiviral selectivity. There was a clear relationship between antiviral activity and the length of the spacer group that links the TSAO molecule with the chelating moiety. A shorter spacer invariably resulted in increased antiviral potency. None of the TSAO-T derivatives were endowed with anti-HIV-2 activity.


2002 ◽  
Vol 76 (3) ◽  
pp. 959-967 ◽  
Author(s):  
Jun-ichi Sakuragi ◽  
Aikichi Iwamoto ◽  
Tatsuo Shioda

ABSTRACT The dimer initiation site/dimer linkage sequence (DIS/DLS) region of the human immunodeficiency virus type 1 (HIV-1) RNA genome is thought to play important roles at various stages of the virus life cycle. Recently we showed that the DIS/DLS region affects RNA-RNA interaction in intact virus particles, by demonstrating that duplication of the region in viral RNA caused the production of virus particles containing partially monomeric RNAs. We have extended this finding and succeeded for the first time in creating mutant particles which contain only monomeric RNAs without modifying any viral proteins. In terms of RNA encapsidation ability, virion density, and protein processing, the mutant particles were comparable to wild-type particles. The level of production of viral DNA by the mutant virus construct in infected cells was also comparable to that of the constructs that produced exclusively dimeric RNA, indicating that monomeric viral RNA could be the template for strand transfer. These results indicated that the RNA dimerization of HIV-1 could be separated from viral RNA packaging and was not absolutely required for RNA packaging, virion maturation, and reverse transcription.


Blood ◽  
1998 ◽  
Vol 92 (6) ◽  
pp. 2084-2092 ◽  
Author(s):  
Egil Lien ◽  
Pål Aukrust ◽  
Anders Sundan ◽  
Fredrik Müller ◽  
Stig S. Frøland ◽  
...  

Abstract Soluble (s) CD14, a marker for monocyte/macrophage activation and a mediator of bacterial lipopolysaccharide (LPS) action, was elevated in serum from human immunodeficiency virus type 1 (HIV- 1)-infected individuals (n = 92) compared with seronegative controls. The highest levels were found in patients with advanced clinical and immunological disease. Patients with ongoing clinical events had significantly higher sCD14 levels than symptomatic HIV-1-infected individuals without clinical events, with especially elevated levels in patients infected with Mycobacterium avium complex (MAC). On longitudinal testing of patients (n = 26) with less than 100 × 106CD4 lymphocytes/L at baseline, we found that increasing sCD14 serum concentrations per time unit were associated with death, whereas no differences in CD4 cell number decrease were found between survivors and nonsurvivors. In vitro studies showed that HIV-1 glycoprotein 120 and purified protein derivative (PPD) from M avium (MAC-PPD) stimulated normal monocytes to release sCD14. Furthermore, MAC-PPD induced tumor necrosis factor (TNF) release from monocytes through interactions with CD14 and, importantly, the addition of sCD14 enhanced this MAC-PPD stimulatory effect. Our findings suggest that the CD14 molecule may be involved in the immunopathogenesis of HIV-1 infection, and it is conceivable that serial determination of sCD14 may give useful predictive information concerning disease progression and survival in HIV-1-infected patients. © 1998 by The American Society of Hematology.


2001 ◽  
Vol 75 (8) ◽  
pp. 3916-3924 ◽  
Author(s):  
Karen M. Duus ◽  
Eric D. Miller ◽  
Jonathan A. Smith ◽  
Grigoriy I. Kovalev ◽  
Lishan Su

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) is frequently attenuated after long-term culture in vitro. The attenuation process probably involves mutations of functions required for replication and pathogenicity in vivo. Analysis of attenuated HIV-1 for replication and pathogenicity in vivo will help to define these functions. In this study, we examined the pathogenicity of an attenuated HIV-1 isolate in a laboratory worker accidentally exposed to a laboratory-adapted HIV-1 isolate. Using heterochimeric SCID-hu Thy/Liv mice as an in vivo model, we previously defined HIV-1 env determinants (HXB/LW) that reverted to replicate in vivo (L. Su, H. Kaneshima, M. L. Bonyhadi, R. Lee, J. Auten, A. Wolf, B. Du, L. Rabin, B. H. Hahn, E. Terwilliger, and J. M. McCune, Virology 227:46–52, 1997). Here we further demonstrate that HIV-1 replication in vivo can be separated from its pathogenic activity, in that the HXB/LW virus replicated to high levels in SCID-hu Thy/Liv mice, with no significant thymocyte depletion. Restoration of the nef gene in the recombinant HXB/LW genome restored its pathogenic activity, with no significant effect on HIV-1 replication in the thymus. Our results suggest that in vitro-attenuated HIV-1 lacks determinants for pathogenicity as well as for replication in vivo. Our data indicate that (i) the replication defect can be recovered in vivo by mutations in the envgene, without an associated pathogenic phenotype, and (ii)nef can function in the HXB/LW clone as a pathogenic factor that does not enhance HIV-1 replication in the thymus. Furthermore, the HXB/LW virus may be used to study mechanisms of HIV-1nef-mediated pathogenesis in vivo.


2000 ◽  
Vol 74 (17) ◽  
pp. 7699-7707 ◽  
Author(s):  
Tim Beaumont ◽  
Silvia Broersen ◽  
Ad van Nuenen ◽  
Han G. Huisman ◽  
Ana-Maria de Roda Husman ◽  
...  

ABSTRACT Development of disease is extremely rare in chimpanzees when inoculated with either T-cell-line-adapted neutralization-sensitive or primary human immunodeficiency virus type 1 (HIV-1), at first excluding a role for HIV-1 neutralization sensitivity in the clinical course of infection. Interestingly, we observed that short-term in vivo and in vitro passage of primary HIV-1 isolates through chimpanzee peripheral blood mononuclear cells (PBMC) resulted in a neutralization-sensitive phenotype. Furthermore, an HIV-1 variant reisolated from a chimpanzee 10 years after experimental infection was still sensitive to neutralization by soluble CD4, the CD4 binding site recognizing antibody IgG1b12 and autologous chimpanzee serum samples, but had become relatively resistant to neutralization by polyclonal human sera and neutralizing monoclonal antibodies. The initial adaptation of HIV-1 to replicate in chimpanzee PBMC seemed to coincide with a selection for viruses with low replicative kinetics. Neither coreceptor usage nor the expression level of CD4, CCR5, or CXCR4 on chimpanzee PBMC compared to human cells could explain the phenotypic changes observed in these chimpanzee-passaged viruses. Our data suggest that the increased neutralization sensitivity of HIV-1 after replication in chimpanzee cells may in part contribute to the long-term asymptomatic HIV-1 infection in experimentally infected chimpanzees.


2011 ◽  
Vol 55 (12) ◽  
pp. 5723-5731 ◽  
Author(s):  
Inge Dierynck ◽  
Herwig Van Marck ◽  
Marcia Van Ginderen ◽  
Tim H. M. Jonckers ◽  
Madhavi N. L. Nalam ◽  
...  

ABSTRACTTMC310911 is a novel human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) structurally closely related to darunavir (DRV) but with improved virological characteristics. TMC310911 has potent activity against wild-type (WT) HIV-1 (median 50% effective concentration [EC50], 14 nM) and a wide spectrum of recombinant HIV-1 clinical isolates, including multiple-PI-resistant strains with decreased susceptibility to currently approved PIs (fold change [FC] in EC50, >10). For a panel of 2,011 recombinant clinical isolates with decreased susceptibility to at least one of the currently approved PIs, the FC in TMC310911 EC50was ≤4 for 82% of isolates and ≤10 for 96% of isolates. The FC in TMC310911 EC50was ≤4 and ≤10 for 72% and 94% of isolates with decreased susceptibility to DRV, respectively.In vitroresistance selection (IVRS) experiments with WT virus and TMC310911 selected for mutations R41G or R41E, but selection of resistant virus required a longer time than IVRS performed with WT virus and DRV. IVRS performed with r13025, a multiple-PI-resistant recombinant clinical isolate, and TMC310911 selected for mutations L10F, I47V, and L90M (FC in TMC310911 EC50= 16). IVRS performed with r13025 in the presence of DRV required less time and resulted in more PI resistance-associated mutations (V32I, I50V, G73S, L76V, and V82I; FC in DRV EC50= 258). The activity against a comprehensive panel of PI-resistant mutants and the limitedin vitroselection of resistant viruses under drug pressure suggest that TMC310911 represents a potential drug candidate for the management of HIV-1 infection for a broad range of patients, including those with multiple PI resistance.


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