scholarly journals PSF Acts through the Human Immunodeficiency Virus Type 1 mRNA Instability Elements To Regulate Virus Expression

2003 ◽  
Vol 23 (18) ◽  
pp. 6618-6630 ◽  
Author(s):  
Andrei S. Zolotukhin ◽  
Daniel Michalowski ◽  
Jenifer Bear ◽  
Sergey V. Smulevitch ◽  
Abdulmaged M. Traish ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Nuclear Export ◽  
Regulatory Elements ◽  
Nucleocytoplasmic Transport ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV) gag/pol and env mRNAs contain cis-acting regulatory elements (INS) that impair stability, nucleocytoplasmic transport, and translation by unknown mechanisms. This downregulation can be counteracted by the viral Rev protein, resulting in efficient export and expression of these mRNAs. Here, we show that the INS region in HIV-1 gag mRNA is a high-affinity ligand of p54nrb/PSF, a heterodimeric transcription/splicing factor. Both subunits bound INS RNA in vitro with similar affinity and specificity. Using an INS-containing subgenomic gag mRNA, we show that it specifically associated with p54nrb in vivo and that PSF inhibited its expression, acting via INS. Studying the authentic HIV-1 mRNAs produced from an infectious molecular clone, we found that PSF affected specifically the INS-containing, Rev-dependent transcripts encoding Gag-Pol and Env. Both subunits contained nuclear export and nuclear retention signals, whereas p54nrb was continuously exported from the nucleus and associated with INS-containing mRNA in the cytoplasm, suggesting its additional role at late steps of mRNA metabolism. Thus, p54nrb and PSF have properties of key factors mediating INS function and likely define a novel mRNA regulatory pathway that is hijacked by HIV-1.

scholarly journals Concerted Action of Multiple cis-Acting Sequences Is Required for Rev Dependence of Late Human Immunodeficiency Virus Type 1 Gene Expression

2000 ◽  
Vol 74 (22) ◽  
pp. 10822-10826 ◽  
Author(s):  
Marcus Graf ◽  
Alexandra Bojak ◽  
Ludwig Deml ◽  
Kurt Bieler ◽  
Hans Wolf ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Nuclear Export ◽  
Regulatory Elements ◽  
Cis Acting ◽  
Immunodeficiency Virus ◽  
Responsive Element ◽  
Hiv 1

ABSTRACT Based on the human immunodeficiency virus type 1 (HIV-1)gag gene, subgenomic reporter constructs have been established allowing the contributions of differentcis-acting elements to the Rev dependency of late HIV-1 gene products to be determined. Modification of intragenic regulatory elements achieved by adapting the codon usage of the complete gene to highly expressed mammalian genes resulted in constitutive nuclear export allowing high levels of Gag expression independent from the Rev/Rev-responsive element system and irrespective of the absence or presence of the isolated major splice donor. Leptomycin B inhibitor studies revealed that the RNAs derived from the codon-optimizedgag gene lacking AU-rich inhibitory elements are directed to a distinct, CRM1-independent, nuclear export pathway.

scholarly journals Negative and Positive mRNA Splicing Elements Act Competitively To Regulate Human Immunodeficiency Virus Type 1 Vif Gene Expression

2008 ◽  
Vol 82 (8) ◽  
pp. 3921-3931 ◽  
Author(s):  
C. M. Exline ◽  
Z. Feng ◽  
C. M. Stoltzfus
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Regulatory Elements ◽  
Mrna Splicing ◽  
Viral Mrnas ◽  
Exon 2 ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Over 40 different human immunodeficiency virus type 1 (HIV-1) mRNAs are produced by alternative splicing of the primary HIV-1 RNA transcripts. In addition, approximately half of the viral RNA remains unspliced and is used as genomic RNA and as mRNA for the Gag and Pol gene products. Regulation of splicing at the HIV-1 3′ splice sites (3′ss) requires suboptimal polypyrimidine tracts, and positive or negative regulation occurs through the binding of cellular factors to cis-acting splicing regulatory elements. We have previously shown that splicing at HIV-1 3′ss A1, which produces single-spliced vif mRNA and promotes the inclusion of HIV exon 2 into both completely and incompletely spliced viral mRNAs, is increased by optimizing the 5′ splice site (5′ss) downstream of exon 2 (5′ss D2). Here we show that the mutations within 5′ss D2 that are predicted to lower or increase the affinity of the 5′ss for U1 snRNP result in reduced or increased Vif expression, respectively. Splicing at 5′ss D2 was not necessary for the effect of 5′ss D2 on Vif expression. In addition, we have found that mutations of the GGGG motif proximal to the 5′ss D2 increase exon 2 inclusion and Vif expression. Finally, we report the presence of a novel exonic splicing enhancer (ESE) element within the 5′-proximal region of exon 2 that facilitates both exon inclusion and Vif expression. This ESE binds specifically to the cellular SR protein SRp75. Our results suggest that the 5′ss D2, the proximal GGGG silencer, and the ESE act competitively to determine the level of vif mRNA splicing and Vif expression. We propose that these positive and negative splicing elements act together to allow the accumulation of vif mRNA and unspliced HIV-1 mRNA, compatible with optimal virus replication.

scholarly journals The Late-Domain-Containing Protein p6 Is the Predominant Phosphoprotein of Human Immunodeficiency Virus Type 1 Particles

2002 ◽  
Vol 76 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
Barbara Müller ◽  
Tilo Patschinsky ◽  
Hans-Georg Kräusslich
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Metabolic Labeling ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
A Minor ◽  
Hiv 1

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.

scholarly journals Ontogeny and Specificities of Mucosal and Blood Human Immunodeficiency Virus Type 1-Specific CD8+ Cytotoxic T Lymphocytes

2003 ◽  
Vol 77 (1) ◽  
pp. 291-300 ◽  
Author(s):  
L. Musey ◽  
Y. Ding ◽  
J. Cao ◽  
J. Lee ◽  
C. Galloway ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cytotoxic T Lymphocyte ◽  
Infected Individual ◽  
Immunodeficiency Virus ◽  
Hiv 1

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.

scholarly journals Use of Coreceptors Other Than CCR5 by Non-Syncytium-Inducing Adult and Pediatric Isolates of Human Immunodeficiency Virus Type 1 Is Rare In Vitro

1998 ◽  
Vol 72 (11) ◽  
pp. 9337-9344 ◽  
Author(s):  
Yi-jun Zhang ◽  
Tatjana Dragic ◽  
Yunzhen Cao ◽  
Leondios Kostrikis ◽  
Douglas S. Kwon ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Entry ◽  
Infected Infant ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

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.

An Approach towards the Synthesis of Potential Metal-Chelating TSAO-T Derivatives as Bidentate Inhibitors of Human Immunodeficiency virus Type 1 Reverse Transcriptase

1998 ◽  
Vol 9 (5) ◽  
pp. 412-421 ◽  
Author(s):  
C Chamorro ◽  
M-J Camarasa ◽  
M-J Pérez-Pérez ◽  
E de Clercq ◽  
J Balzarini ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Reverse Transcriptase ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Parent Compound ◽  
Immunodeficiency Virus ◽  
Anti Hiv ◽  
Hiv 1

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.

Elevated Levels of Serum-Soluble CD14 in Human Immunodeficiency Virus Type 1 (HIV-1) Infection: Correlation to Disease Progression and Clinical Events

Blood ◽  
1998 ◽  
Vol 92 (6) ◽  
pp. 2084-2092 ◽  
Author(s):  
Egil Lien ◽  
Pål Aukrust ◽  
Anders Sundan ◽  
Fredrik Müller ◽  
Stig S. Frøland ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Disease Progression ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cell Number ◽  
Clinical Events ◽  
Immunodeficiency Virus ◽  
Hiv 1

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.

scholarly journals Separation of Human Immunodeficiency Virus Type 1 Replication from nef-Mediated Pathogenesis in the Human Thymus

2001 ◽  
Vol 75 (8) ◽  
pp. 3916-3924 ◽  
Author(s):  
Karen M. Duus ◽  
Eric D. Miller ◽  
Jonathan A. Smith ◽  
Grigoriy I. Kovalev ◽  
Lishan Su
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
In Vivo Model ◽  
Immunodeficiency Virus ◽  
Pathogenic Activity ◽  
Hiv 1

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.

scholarly journals Increased Neutralization Sensitivity and Reduced Replicative Capacity of Human Immunodeficiency Virus Type 1 after Short-Term In Vivo or In Vitro Passage through Chimpanzees

2000 ◽  
Vol 74 (17) ◽  
pp. 7699-7707 ◽  
Author(s):  
Tim Beaumont ◽  
Silvia Broersen ◽  
Ad van Nuenen ◽  
Han G. Huisman ◽  
Ana-Maria de Roda Husman ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Short Term ◽  
Neutralization Sensitivity ◽  
Immunodeficiency Virus ◽  
Hiv 1

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.

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