scholarly journals Interaction of the human T-cell lymphotropic virus type 1 tax transactivator with transcription factor IIA.

1996 ◽  
Vol 16 (9) ◽  
pp. 4656-4664 ◽  
Author(s):  
K E Clemens ◽  
G Piras ◽  
M F Radonovich ◽  
K S Choi ◽  
J F Duvall ◽  
...  
Keyword(s):  
Transcription Factor ◽  
T Cell ◽  
T Lymphocytes ◽  
Virus Type ◽  
Expression Vectors ◽  
Human T Lymphocytes ◽  
Cell Extracts ◽  
Human T Cell

The Tax protein of human T-cell lymphotropic virus type 1 (HTLV-1) is a 40-kDa transcriptional activator which is critical for HTLV-1 gene regulation and virus-induced cellular transformation. Tax is localized to the DNA through its interaction with the site-specific activators cyclic AMP-responsive element-binding protein, NF-kappaB, and serum response factor. It has been suggested that the recruitment of Tax to the DNA positions Tax for interaction with the basal transcriptional machinery. On the basis of several independent assays, we now report a physical and functional interaction between Tax and the transcription factor, TFIIA. First, Tax was found to interact with the 35-kDa (alpha) subunit of TFIIA in the yeast two-hybrid interaction system. Importantly, two previously characterized mutants with point mutations in Tax, M32 (Y196A, K197S) and M41 (H287A, P288S), which were shown to be defective in Tax-activated transcription were unable to interact with TFIIA in this assay. Second, a glutathione-S-transferase (GST) affinity-binding assay showed that the interaction of holo-TFIIA with GST-Tax was 20-fold higher than that observed with either the GST-Tax M32 activation mutant or the GST control. Third, a coimmunoprecipitation assay showed that in HTLV-1-infected human T lymphocytes, Tax and TFIIA were associated. Finally, TFIIA facilitates Tax transactivation in vitro and in vivo. In vitro transcription studies showed reduced levels of Tax-activated transcription in cell extracts depleted of TFIIA. In addition, transfection of human T lymphocytes with TFIIA expression vectors enhanced Tax-activated transcription of an HTLV-1 long terminal repeat-chloramphenicol acetyltransferase reporter construct. Our study suggests that the interaction of Tax with the transcription factor TFIIA may play a role in Tax-mediated transcriptional activation.

scholarly journals In vitro infection of human macrophages with human T-cell leukemia virus type 1

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1598-1606 ◽  
Author(s):  
T de Revel ◽  
A Mabondzo ◽  
G Gras ◽  
B Delord ◽  
P Roques ◽  
...  
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human Macrophages ◽  
Human T Cell ◽  
T Cell Leukemia Virus

Abstract The tropism of the human T-cell leukemia virus type 1 (HTLV-1) for the cells of monocyte-macrophage lineage was evaluated by the coculture of blood monocyte-derived macrophages, with irradiated cells of HTLV-1 producing cell lines MT2 or C91/PL. The susceptibility to HTLV-1 was assessed by the detection of viral DNA using the polymerase chain reaction method. HTLV-1 gene expression in the cells was detected using in situ hybridization and by immunofluorescent staining of viral antigen. The presence of type C virus-like particles detected by electron microscopy and the ability to infect normal cord blood lymphocytes demonstrated that the infected macrophages produced infectious virus. These results indicate that human macrophages are susceptible in vitro to productive HTLV-1 infection, and thus might be involved in the pathogenesis of HTLV-1-related diseases.

scholarly journals Candidate Polyanionic Microbicides Inhibit Human T-Cell Lymphotropic Virus Type 1 Receptor Interactions, Cell-Free Infection, and Cell-Cell Spread

2008 ◽  
Vol 53 (2) ◽  
pp. 678-687 ◽  
Author(s):  
Daniela Romer ◽  
David W. Brighty ◽  
Cynthia L. Robson ◽  
Quentin J. Sattentau
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Inflammatory Diseases ◽  
Sexual Transmission ◽  
Spastic Paraparesis ◽  
Virus Spread ◽  
Human T Cell ◽  
Cell Cell

ABSTRACT The human T-cell lymphotropic virus type 1 (HTLV-1) is the cause of adult T-cell leukemia and inflammatory diseases including HTLV-1-associated myelopathy/tropical spastic paraparesis. HTLV-1 can be transmitted through sexual contact, mother-to-child transmission, and exposure to contaminated blood. Microbicides are agents that interfere with microbial infectivity at mucous membranes, and candidates are under development for use against sexually transmitted viruses such as human immunodeficiency virus type 1. We previously demonstrated that cell surface polyanionic heparan sulfate proteoglycans bind the HTLV-1 envelope glycoprotein surface subunit gp46, facilitating cell-cell and cell-free virus spread in vitro. We now show, using assays for Env-receptor binding inhibition, Env-induced cell-cell fusion, cell-cell virus spread, and pseudotype HTLV-1 infectivity, that the soluble polyanions PRO 2000 and dextran sulfate are potent inhibitors of HTLV-1 spread in vitro, with PRO 2000 being the more promising candidate. The results of these studies suggest that candidate topical microbicides may be of use in reducing HTLV-1 sexual transmission.

scholarly journals Effect of Lamivudine on Transmission of Human T-Cell Lymphotropic Virus Type 1 to Adult Peripheral Blood Mononuclear Cells In Vitro

2002 ◽  
Vol 46 (9) ◽  
pp. 3080-3083 ◽  
Author(s):  
Emanuela Balestrieri ◽  
Giancarlo Forte ◽  
Claudia Matteucci ◽  
Antonio Mastino ◽  
Beatrice Macchi
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Peripheral Blood Mononuclear ◽  
Human T Cell ◽  
Blood Mononuclear Cells

ABSTRACT The effects of lamivudine (3TC) on in vitro infection of peripheral blood mononuclear cells (PBMC) from healthy donors with human T-cell lymphotropic virus type 1 (HTLV-1) were investigated. Direct measures of viral replication (viral DNA, RNA, and protein) all gave similar, very high 50% inhibitory concentrations in comparison with those previously reported for zidovudine. Nevertheless, 3TC inhibited HTLV-1-driven long-term growth of infected PBMC in vitro at concentrations (6.25 μM) which had poor or no direct antiviral effects, suggesting that another mechanism may be playing a role.

scholarly journals Molecular Interactions Involved in the Transactivation of the Human T-Cell Leukemia Virus Type 1 Promoter Mediated by Tax and CREB-2 (ATF-4)

2000 ◽  
Vol 20 (10) ◽  
pp. 3470-3481 ◽  
Author(s):  
Frederic Gachon ◽  
Sabine Thebault ◽  
Annick Peleraux ◽  
Christian Devaux ◽  
Jean-Michel Mesnard
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Leukemia Virus ◽  
Viral Transcription ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Leukemia Virus

ABSTRACT The human T-cell leukemia virus type 1 (HTLV-1) Tax protein activates viral transcription through three 21-bp repeats located in the U3 region of the HTLV-1 long terminal repeat and called Tax-responsive elements (TxREs). Each TxRE contains nucleotide sequences corresponding to imperfect cyclic AMP response elements (CRE). In this study, we demonstrate that the bZIP transcriptional factor CREB-2 is able to bind in vitro to the TxREs and that CREB-2 binding to each of the 21-bp motifs is enhanced by Tax. We also demonstrate that Tax can weakly interact with CREB-2 bound to a cellular palindromic CRE motif such as that found in the somatostatin promoter. Mutagenesis of Tax and CREB-2 demonstrates that both N- and C-terminal domains of Tax and the C-terminal region of CREB-2 are required for direct interaction between the two proteins. In addition, the Tax mutant M47, defective for HTLV-1 activation, is unable to form in vitro a ternary complex with CREB-2 and TxRE. In agreement with recent results suggesting that Tax can recruit the coactivator CREB-binding protein (CBP) on the HTLV-1 promoter, we provide evidence that Tax, CREB-2, and CBP are capable of cooperating to stimulate viral transcription. Taken together, our data highlight the major role played by CREB-2 in Tax-mediated transactivation.

In vitro infection of human macrophages with human T-cell leukemia virus type 1

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1598-1606
Author(s):  
T de Revel ◽  
A Mabondzo ◽  
G Gras ◽  
B Delord ◽  
P Roques ◽  
...  
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human Macrophages ◽  
Human T Cell ◽  
T Cell Leukemia Virus

The tropism of the human T-cell leukemia virus type 1 (HTLV-1) for the cells of monocyte-macrophage lineage was evaluated by the coculture of blood monocyte-derived macrophages, with irradiated cells of HTLV-1 producing cell lines MT2 or C91/PL. The susceptibility to HTLV-1 was assessed by the detection of viral DNA using the polymerase chain reaction method. HTLV-1 gene expression in the cells was detected using in situ hybridization and by immunofluorescent staining of viral antigen. The presence of type C virus-like particles detected by electron microscopy and the ability to infect normal cord blood lymphocytes demonstrated that the infected macrophages produced infectious virus. These results indicate that human macrophages are susceptible in vitro to productive HTLV-1 infection, and thus might be involved in the pathogenesis of HTLV-1-related diseases.

Selective Ablation of Human T-Cell Lymphotropic Virus Type 1 p12I Reduces Viral Infectivity In Vivo

Blood ◽  
1998 ◽  
Vol 91 (12) ◽  
pp. 4701-4707 ◽  
Author(s):  
Nathaniel D. Collins ◽  
Garret C. Newbound ◽  
Björn Albrecht ◽  
Jennifer L. Beard ◽  
Lee Ratner ◽  
...  
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Rabbit Model ◽  
Etiologic Agent ◽  
Peripheral Blood Mononuclear ◽  
Antigen Production ◽  
Human T Cell

Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia and HTLV-1-associated myelopathy. Novel, yet conserved RNA transcripts encoded from open reading frames (ORFs) I and II of the viral pX region are expressed both in vitro and in infected individuals. The ORF I mRNA encodes the protein p12I, which has been shown to localize to cellular endomembranes, cooperate with bovine papillomavirus E5 in transformation, as well as bind to the IL-2 receptor β and γ chains and the H+ vacuolar ATPase. It is unknown what role p12I plays in the viral life cycle. Using an infectious molecular clone of HTLV-1 (ACH) and a derivative clone, ACH.p12I, which fails to produce the p12Imessage, we investigated the importance of p12I in infected primary cells and in a rabbit model of the infection. ACH.p12I was infectious in vitro as shown by viral passage in culture and no qualitative or quantitative differences were noted between ACH and ACH.p12I in posttransfection viral antigen production. However, in contrast to ACH, ACH.p12I failed to establish persistent infection in vivo as indicated by reduced anti-HTLV-1 antibody responses, failure to demonstrate viral p19 antigen production in peripheral blood mononuclear cell (PBMC) cultures, and only transient detection of provirus by polymerase chain reaction in PBMC from ACH.p12I-inoculated rabbits. These results are the first to show the essential role of HTLV-1 p12I in the establishment of persistent viral infection in vivo and suggest potential new targets in antiviral strategies to prevent HTLV-1 infection.

scholarly journals Immortalization of CD4+ and CD8+ T Lymphocytes by Human T-Cell Leukemia Virus Type 1 Tax Mutants Expressed in a Functional Molecular Clone

1999 ◽  
Vol 73 (6) ◽  
pp. 4856-4865 ◽  
Author(s):  
Michael D. Robek ◽  
Lee Ratner
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
Virus Type ◽  
Leukemia Virus ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Molecular Clone ◽  
Human T Cell ◽  
T Cell Leukemia Virus

ABSTRACT The human T-cell leukemia virus type 1 (HTLV-1) transcriptionaltrans-activator Tax has been demonstrated to have transforming activity in multiple cell culture and transgenic-mouse models. In addition to activating transcription from the viral long terminal repeat (LTR) through the cyclic AMP response element binding protein/activating transcription factor (CREB/ATF) family of transcription factors, Tax activates the expression of multiple cellular promoters through the NF-κB pathway of transcriptional activation. The Tax mutants M22 and M47 have previously been demonstrated to selectively abrogate the ability of Tax to activate transcription through the NF-κB or CREB/ATF pathway, respectively. These mutations were introduced in the tax gene of the ACH functional molecular clone of HTLV-1, and virus produced from the mutant ACH clones was examined for the ability to replicate and immortalize primary human lymphocytes. While virus derived from the clone containing the M47 mutation retained the ability to immortalize T lymphocytes, the M22 mutant lost the ability to immortalize infected cells. These results indicate that activation of the CREB/ATF pathway by Tax is dispensable for the immortalization of T cells by HTLV-1, whereas activation of the NF-κB pathway may be critical.

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