scholarly journals Characterization of the human immunodeficiency virus type 1 enhancer-binding proteins from the human T-cell line Jurkat

1990 ◽  
Vol 265 (2) ◽  
pp. 547-554 ◽  
Author(s):  
M Korner ◽  
A H Bellan ◽  
A T Brini ◽  
W L Farrar
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Interleukin 2 ◽  
Exchange Chromatography ◽  
Jurkat Cells ◽  
Human T Cell ◽  
Immunodeficiency Virus ◽  
Hiv 1

The transcription of the human immunodeficiency virus type 1 (HIV-1) is under the control of cellular proteins that bind to the viral long terminal repeat (LTR). Among the protein-binding regions of the HIV-1 LTR is the transcription-enhancer region. We show that at least one inducible, C1, and one constitutive, C2, protein can bind to the HIV enhancer in Jurkat cells. The two proteins differ in their surface charge, since they are separable by anion-exchange chromatography. Bivalent cations such as Mg2+ and Zn2+ differentially affect their binding to oligonucleotides which contain the HIV-enhancer domain. Both C1 and C2 proteins also bind to a similar sequence found in the interleukin-2-receptor alpha-subunit enhancer. The inducible C1 protein was partially purified by three chromatographic steps and characterized by u.v. cross-linking as a 47 kDa protein.

scholarly journals Modulation of Sp1 Phosphorylation by Human Immunodeficiency Virus Type 1 Tat

1998 ◽  
Vol 72 (4) ◽  
pp. 2615-2629 ◽  
Author(s):  
Rene F. Chun ◽  
O. J. Semmes ◽  
Christine Neuveut ◽  
Kuan-Teh Jeang
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Kinase Inhibitor ◽  
Jurkat Cells ◽  
Physical Interaction ◽  
Dependent Manner ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT We previously reported (K. T. Jeang, R. Chun, N. H. Lin, A. Gatignol, C. G. Glabe, and H. Fan, J. Virol. 67:6224–6233, 1993) that human immunodeficiency virus type 1 (HIV-1) Tat and Sp1 form a protein-protein complex. Here, we have characterized the physical interaction and a functional consequence of Tat-Sp1 contact. Using in vitro protein chromatography, we mapped the region in Tat that contacts Sp1 to amino acids 30 to 55. We found that in cell-free reactions, Tat augmented double-stranded DNA-dependent protein kinase (DNA-PK)-mediated Sp1 phosphorylation in a contact-dependent manner. Tat mutants that do not bind Sp1 failed to influence phosphorylation of the latter. In complementary experiments, we also found that Tat forms protein-protein contacts with DNA-PK. We confirmed that in HeLa and Jurkat cells, Tat expression indeed increased the intracellular amount of phosphorylated Sp1 in a manner consistent with the results of cell-free assays. Furthermore, using two phosphatase inhibitors and a kinase inhibitor, we demonstrated a modulation of reporter gene expression as a consequence of changes in Sp1 phosphorylation. Taken together, these findings suggest that activity at the HIV-1 promoter is influenced by phosphorylation of Sp1 which is affected by Tat and DNA-PK.

scholarly journals Impairment of Human Immunodeficiency Virus Type 1 (HIV-1) Entry into Jurkat T Cells by Constitutive Expression of the HIV-1 Vpr Protein: Role of CD4 Down-Modulation

2000 ◽  
Vol 74 (21) ◽  
pp. 10207-10211 ◽  
Author(s):  
Lucia Conti ◽  
Barbara Varano ◽  
M. Cristina Gauzzi ◽  
Paola Matarrese ◽  
Maurizio Federico ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Constitutive Expression ◽  
Jurkat Cells ◽  
Cell Functions ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Jurkat T-cell clones, stably expressing the human immunodeficiency virus type 1 (HIV-1) Vpr protein, exhibited an impaired susceptibility to HIV-1 infection. A marked down-modulation of surface CD4 receptors was detected in Vpr-expressing clones with respect to control cells. Likewise, a reduced CD4 expression was also observed in parental Jurkat cells infected with wild-type but not with Vpr-mutant HIV-1. Notably, Vpr-expressing clones were fully susceptible to infection with a vesicular stomatitis virus G protein-pseudotyped HIV-1 virus, indicating that a block at the level of viral entry was responsible for the inhibition of viral replication. The effect exerted by Vpr on HIV replication and CD4 expression suggests that this protein can regulate both the establishment of a productive HIV-1 infection and CD4-mediated T-cell functions.

scholarly journals Evidence for Budding of Human Immunodeficiency Virus Type 1 Selectively from Glycolipid-Enriched Membrane Lipid Rafts

2000 ◽  
Vol 74 (7) ◽  
pp. 3264-3272 ◽  
Author(s):  
Dzung H. Nguyen ◽  
James E. K. Hildreth
Keyword(s):  
Human Immunodeficiency Virus ◽  
Lipid Rafts ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Matrix Protein ◽  
Viral Envelope ◽  
Jurkat Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT A number of recent studies have demonstrated the significance of detergent-insoluble, glycolipid-enriched membrane domains or lipid rafts, especially in regard to activation and signaling in T lymphocytes. These domains can be viewed as floating rafts composed of sphingolipids and cholesterol which sequester glycosylphosphatidylinositol (GPI)-linked proteins, such as Thy-1 and CD59. CD45, a 200-kDa transmembrane phosphatase protein, is excluded from these domains. We have found that human immunodeficiency virus type 1 (HIV-1) particles produced by infected T-cell lines acquire the GPI-linked proteins Thy-1 and CD59, as well as the ganglioside GM1, which is known to partition preferentially into lipid rafts. In contrast, despite its high expression on the cell surface, CD45 was poorly incorporated into virus particles. Confocal fluorescence microscopy revealed that HIV-1 proteins colocalized with Thy-1, CD59, GM1, and a lipid raft-specific fluorescent lipid, DiIC16(3), in uropods of infected Jurkat cells. CD45 did not colocalize with HIV-1 proteins and was excluded from uropods. Dot immunoassay of Triton X-100-extracted membrane fractions revealed that HIV-1 p17 matrix protein and gp41 were present in the detergent-resistant fractions and that [3H]myristic acid-labeled HIV Gag showed a nine-to-one enrichment in lipid rafts. We propose a model for the budding of HIV virions through lipid rafts whereby host cell cholesterol, sphingolipids, and GPI-linked proteins within these domains are incorporated into the viral envelope, perhaps as a result of preferential sorting of HIV Gag to lipid rafts.

scholarly journals Long-Term Restriction by APOBEC3F Selects Human Immunodeficiency Virus Type 1 Variants with Restored Vif Function

2010 ◽  
Vol 84 (19) ◽  
pp. 10209-10219 ◽  
Author(s):  
John S. Albin ◽  
Guylaine Haché ◽  
Judd F. Hultquist ◽  
William L. Brown ◽  
Reuben S. Harris
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Term Selection ◽  
Human T Cell ◽  
Immunodeficiency Virus ◽  
T Cell Lines ◽  
Hiv 1

ABSTRACT Tandem stop mutations K26X and H27X in human immunodeficiency virus type 1 (HIV-1) vif compromise virus replication in human T-cell lines that stably express APOBEC3F (A3F) or APOBEC3G (A3G). We previously reported that partial resistance to A3G could develop in these Vif-deficient viruses through a nucleotide A200-to-T/C transversion and a vpr null mutation, but these isolates were still susceptible to restriction by A3F. Here, long-term selection experiments were done to determine how these A3G-selected isolates might evolve to spread in the presence of A3F. We found that A3F, like A3G, is capable of potent, long-term restriction that eventually selects for heritable resistance. In all 7 instances, the selected isolates had restored Vif function to cope with A3F activity. In two isolates, Vif Q26-Q27 and Y26-Q27, the resistance phenotype recapitulated in molecular clones, but when the selected vif alleles were analyzed in the context of an otherwise wild-type viral background, a different outcome emerged. Although HIV-1 clones with Vif Q26-Q27 or Y26-Q27 were fully capable of overcoming A3F, they were now susceptible to restriction by A3G. Concordant with prior studies, a lysine at position 26 proved essential for A3G neutralization. These data combine to indicate that A3F and A3G exert at least partly distinct selective pressures and that Vif function may be essential for the virus to replicate in the presence of A3F.

scholarly journals Potent and Specific Inhibition of Human Immunodeficiency Virus Type 1 Replication by RNA Interference

2002 ◽  
Vol 76 (18) ◽  
pp. 9225-9231 ◽  
Author(s):  
Glen A. Coburn ◽  
Bryan R. Cullen
Keyword(s):  
Human Immunodeficiency Virus ◽  
Rna Interference ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Human Cells ◽  
Mrna Targets ◽  
Human T Cell ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Synthetic small interfering RNAs (siRNAs) have been shown to induce the degradation of specific mRNA targets in human cells by inducing RNA interference (RNAi). Here, we demonstrate that siRNA duplexes targeted against the essential Tat and Rev regulatory proteins encoded by human immunodeficiency virus type 1 (HIV-1) can specifically block Tat and Rev expression and function. More importantly, we show that these same siRNAs can effectively inhibit HIV-1 gene expression and replication in cell cultures, including those of human T-cell lines and primary lymphocytes. These observations demonstrate that RNAi can effectively block virus replication in human cells and raise the possibility that RNAi could provide an important innate protective response, particularly against viruses that express double-stranded RNAs as part of their replication cycle.

scholarly journals The Orphan Seven-Transmembrane Receptor Apj Supports the Entry of Primary T-Cell-Line-Tropic and Dualtropic Human Immunodeficiency Virus Type 1

1998 ◽  
Vol 72 (7) ◽  
pp. 6113-6118 ◽  
Author(s):  
Hyeryun Choe ◽  
Michael Farzan ◽  
Miriam Konkel ◽  
Kathleen Martin ◽  
Ying Sun ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Cell Line ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Interleukin 2 ◽  
Target Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) enters target cells by sequential binding to CD4 and specific seven-transmembrane-segment (7TMS) coreceptors. Viruses use the chemokine receptor CCR5 as a coreceptor in the early, asymptomatic stages of HIV-1 infection but can adapt to the use of other receptors such as CXCR4 and CCR3 as the infection proceeds. Here we identify one such coreceptor, Apj, which supported the efficient entry of several primary T-cell-line tropic (T-tropic) and dualtropic HIV-1 isolates and the simian immunodeficiency virus SIVmac316. Another 7TMS protein, CCR9, supported the less efficient entry of one primary T-tropic isolate. mRNAs for both receptors were present in phytohemagglutinin- and interleukin-2-activated peripheral blood mononuclear cells. Apj and CCR9 share with other coreceptors for HIV-1 and SIV an N-terminal region rich in aromatic and acidic residues. These results highlight properties common to 7TMS proteins that can function as HIV-1 coreceptors, and they may contribute to an understanding of viral evolution in infected individuals.

scholarly journals TFII-I Regulates Induction of Chromosomally Integrated Human Immunodeficiency Virus Type 1 Long Terminal Repeat in Cooperation with USF

2005 ◽  
Vol 79 (7) ◽  
pp. 4396-4406 ◽  
Author(s):  
Jiguo Chen ◽  
Tom Malcolm ◽  
Mario C. Estable ◽  
Robert G. Roeder ◽  
Ivan Sadowski
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
T Cell Activation ◽  
Cell Activation ◽  
Jurkat Cells ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) replication is coupled to T-cell activation through its dependence on host cell transcription factors. Despite the enormous sequence variability of these factors, several cis elements for host factors are highly conserved within the 5′ long terminal repeats (LTRs) of viruses from AIDS patients; among these is the RBEIII upstream element for the Ras response element binding factor 2 (RBF-2). Here we show that RBF-2 is comprised of a USF1/USF2 heterodimer and TFII-I, which bind cooperatively to RBEIII. Recombinant USF1/USF2 binds to the RBEIII core sequence 160-fold less efficiently than it binds to an E box element, but the interaction with RBEIII is stimulated by TFII-I. Chromosomally integrated HIV-1 LTRs bearing an RBEIII mutation have slightly elevated basal transcription in unstimulated Jurkat cells but are unresponsive to cross-linking of the T-cell receptor or stimulation with phorbol myristate acetate (PMA) and ionomycin. Induction is inhibited by dominant interfering USF and TFII-I but not by the dominant negative I-κB protein. USF1, USF2, and TFII-I bind to the integrated wild-type LTR in unstimulated cells and become phosphorylated during the induction of transcription upon stimulation with PMA. These results demonstrate that USF1/USF2 and TFII-I interact cooperatively at the upstream RBEIII element and are necessary for the induction of latent HIV-1 in response to T-cell activation signals.

scholarly journals Human Immunodeficiency Virus Type 1 Replication Is Modulated by Host Cyclophilin A Expression Levels

1998 ◽  
Vol 72 (8) ◽  
pp. 6430-6436 ◽  
Author(s):  
Lei Yin ◽  
Douglas Braaten ◽  
Jeremy Luban
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cyclophilin A ◽  
Jurkat Cells ◽  
Expression Levels ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) Gag and the cellular protein cyclophilin A form an essential complex in the virion core: virions produced by proviruses encoding Gag mutants with decreased cyclophilin A affinity exhibit attenuated infectivity, as do virions produced in the presence of the competitive inhibitor cyclosporine. The A224E Gag mutant has no effect on cyclophilin A affinity but renders HIV-1 replication cyclosporine resistant in Jurkat T cells. In contrast, A224E mutant virus is dead in H9 T cells, although replication is rescued by cyclosporine or by expression in cis of a Gag mutant that decreases cyclophilin A-affinity. The observation that disruption of the Gag-cyclophilin A interaction rescues A224E mutant replication in H9 cells prompted experiments which revealed that, relative to Jurkat cells, H9 cells express greater quantities of cyclophilin A. The resulting larger quantity of cyclophilin A shown to be packaged into virions produced by H9 cells is presumably disruptive to the A224E mutant virion core. Further evidence that increased cyclophilin A expression in H9 cells is of functional relevance was provided by the finding that Gag mutants with decreased cyclophilin A affinity are dead in Jurkat cells but capable of replication in H9 cells. Similarly, cyclosporine concentrations which inhibit wild-type HIV-1 replication in Jurkat cells stimulate HIV-1 replication in H9 cells. These results suggest that HIV-1 virion infectivity imposes narrow constraints upon cyclophilin A stoichiometry in virions and that infectivity is finely tuned by host cyclophilin A expression levels.

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