scholarly journals Regulation of Human Polyomavirus JC Virus Gene Transcription by AP-1 in Glial Cells

2003 ◽  
Vol 77 (1) ◽  
pp. 665-672 ◽  
Author(s):  
Beata Sadowska ◽  
Robert Barrucco ◽  
Kamel Khalili ◽  
Mahmut Safak
Keyword(s):  
Glial Cells ◽  
Gene Transcription ◽  
Dna Sequences ◽  
Jc Virus ◽  
Family Members ◽  
Ectopic Expression ◽  
Human Polyomavirus ◽  
Viral Gene ◽  
Infection Cycle ◽  
Binding Studies

ABSTRACT The activating transcription factor 1 (AP-1) family of proteins consists of a large number of inducible factors that are implicated in many biological processes, including cellular and viral gene expression, cell proliferation, differentiation, and tumorigenesis. Here, we investigated the role of the AP-1 family members c-Jun and c-Fos in transcriptional regulation of the JC virus (JCV) promoter in glial cells. DNA binding studies demonstrated the specific association of c-Jun with its DNA sequences corresponding to the AP-1 site within the JCV promoter. Functional analysis of the promoter showed that ectopic expression of c-Jun and c-Fos results in an additive activation of the JCV early and late promoters. Further functional assays indicated that the JCV AP-1 binding site is sufficient to confer responsiveness to both c-Jun/c-Fos- and UV-induced activation when transposed to a heterologous promoter. Analysis of c-Jun expression during the viral infection cycle by Western blotting revealed that c-Jun is posttranslationally modified by phosphorylation and its protein level is substantially increased at the late phases of infection cycle. Altogether, our findings indicate that AP-1 family members may play a role in the pathogenesis of JCV-induced disease in the human brain by modulating JCV gene transcription.

scholarly journals Functional Interaction between JC Virus Late Regulatory Agnoprotein and Cellular Y-Box Binding Transcription Factor, YB-1

2002 ◽  
Vol 76 (8) ◽  
pp. 3828-3838 ◽  
Author(s):  
Mahmut Safak ◽  
Beata Sadowska ◽  
Robert Barrucco ◽  
Kamel Khalili
Keyword(s):  
Transcription Factor ◽  
Glial Cells ◽  
Gene Transcription ◽  
Jc Virus ◽  
Lytic Cycle ◽  
Human Polyomavirus ◽  
Regulatory Function ◽  
Infection Cycle ◽  
Functional Interaction ◽  
Amino Terminal

ABSTRACT Human polyomavirus JC virus (JCV) is a causative agent of progressive multifocal leukoencephalopathy which results from lytic infection of glial cells. Although significant progress has been made in understanding the regulation of JCV gene transcription, the mechanism(s) underlying the viral lytic cycle remains largely unknown. We recently reported that the JCV late auxiliary Agnoprotein may have a regulatory role in JCV gene transcription and replication. Here, we investigated its regulatory function in viral gene transcription through its physical and functional interaction with YB-1, a cellular transcription factor which contributes to JCV gene expression in glial cells. Time course studies revealed that Agnoprotein is first detected at day 3 postinfection and that its level increased during the late stage of the infection cycle. Agnoprotein is mainly localized to the cytoplasmic compartment of the infected cell, with high concentrations found in the perinuclear region. While the position of Agnoprotein throughout the infection cycle remained relatively unaltered, the subcellular distribution of YB-1 between the cytoplasm and nucleus changed. Results from coimmunoprecipitation and glutathione S-transferase pull-down experiments revealed that Agnoprotein physically interacts with YB-1 and that the amino-terminal region of Agnoprotein, between residues 1 and 36, is critical for this association. Further investigation of this interaction by functional assays demonstrated that Agnoprotein negatively regulates YB-1-mediated gene transcription and that the region corresponding to residues 1 to 36 of Agnoprotein is important for the observed regulatory event. Taken together, these data demonstrate that the interaction of the viral late regulatory Agnoprotein and cellular Y-box binding factor YB-1 modulates transcriptional activity of JCV promoters.

scholarly journals NFAT4 Is Required for JC Virus Infection of Glial Cells

2006 ◽  
Vol 80 (24) ◽  
pp. 12079-12085 ◽  
Author(s):  
Kate Manley ◽  
Bethany A. O'Hara ◽  
Gretchen V. Gee ◽  
Carl P. Simkevich ◽  
John M. Sedivy ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Glial Cells ◽  
Demyelinating Disease ◽  
Jc Virus ◽  
Human Polyomavirus ◽  
Luciferase Reporter ◽  
Viral Gene ◽  
Activated T Cells ◽  
Immunosuppressed Patients ◽  
Reporter Assays

ABSTRACT The human polyomavirus JC virus (JCV) infects 70% of the population worldwide. In immunosuppressed patients, JCV infection can lead to progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease of the central nervous system (CNS). The majority of PML cases occur in the setting of human immunodeficiency virus (HIV) infection, and it has been suggested that the link between HIV and the development of PML is in part related to the production of numerous cytokines in the CNS during HIV infection. To examine the link between the expression of inflammatory cytokines and JCV infection, we tested an anti-inflammatory compound, cyclosporine A (CsA), for its ability to block JCV infection of glial cells. We found that CsA inhibited JCV infection by preventing the activation of the transcription factor nuclear factor of activated T cells 4 (NFAT4). Luciferase reporter assays and chromatin immunoprecipitation assays revealed that NFAT4 directly bound the JCV promoter during infection and was important for the activation of both early and late transcription. In addition, the expression of the JCV early viral gene products increased NFAT activity to further aid viral transcription. The necessity of NFAT for JCV infection suggests that calcium signaling and the activation of NFAT in glial cells are required for JCV infection of the CNS.

scholarly journals Pathogenesis and molecular biology of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain.

1992 ◽  
Vol 5 (1) ◽  
pp. 49-73 ◽  
Author(s):  
E O Major ◽  
K Amemiya ◽  
C S Tornatore ◽  
S A Houff ◽  
J R Berger
Keyword(s):  
B Cells ◽  
Virus Infection ◽  
Molecular Biology ◽  
Progressive Multifocal Leukoencephalopathy ◽  
Dna Sequences ◽  
Jc Virus ◽  
Nucleoside Analogs ◽  
Sufficient Evidence ◽  
Viral Gene ◽  
The Brain

Studies of the pathogenesis and molecular biology of JC virus infection over the last two decades have significantly changed our understanding of progressive multifocal leukoencephalopathy, which can be described as a subacute viral infection of neuroglial cells that probably follows reactivation of latent infection rather than being the consequence of prolonged JC virus replication in the brain. There is now sufficient evidence to suggest that JC virus latency occurs in kidney and B cells. However, JC virus isolates from brain or kidney differ in the regulatory regions of their viral genomes which are controlled by host cell factors for viral gene expression and replication. DNA sequences of noncoding regions of the viral genome display a certain heterogeneity among isolates from brain and kidney. These data suggest that an archetypal strain of JC virus exists whose sequence is altered during replication in different cell types. The JC virus regulatory region likely plays a significant role in establishing viral latency and must be acted upon for reactivation of the virus. A developing hypothesis is that reactivation takes place from latently infected B lymphocytes that are activated as a result of immune suppression. JC virus enters the brain in the activated B cell. Evidence for this mechanism is the detection of JC virus DNA in peripheral blood lymphocytes and infected B cells in the brains of patients with progressive multifocal leukoencephalopathy. Once virus enters the brain, astrocytes as well as oligodendrocytes support JC virus multiplication. Therefore, JC virus infection of neuroglial cells may impair other neuroglial functions besides the production and maintenance of myelin. Consequently our increased understanding of the pathogenesis of progressive multifocal leukoencephalopathy suggests new ways to intervene in JC virus infection with immunomodulation therapies. Perhaps along with trials of nucleoside analogs or interferon administration, this fatal disease, for which no consensus of antiviral therapy exists, may yield to innovative treatment protocols.

scholarly journals Reciprocal Interaction between Two Cellular Proteins, Purα and YB-1, Modulates Transcriptional Activity of JCVCY in Glial Cells

1999 ◽  
Vol 19 (4) ◽  
pp. 2712-2723 ◽  
Author(s):  
Mahmut Safak ◽  
Gary L. Gallia ◽  
Kamel Khalili
Keyword(s):  
Amino Acids ◽  
Glial Cells ◽  
Ectopic Expression ◽  
Direct Interaction ◽  
Regulatory Proteins ◽  
Cooperative Interaction ◽  
Cellular Proteins ◽  
Human Polyomavirus ◽  
Band Shift ◽  
Sequence Element

ABSTRACT Cross communication between regulatory proteins is an important event in the control of eukaryotic gene transcription. Here we have examined the structural and functional interaction between two cellular regulatory proteins, YB-1 and Purα, on the 23-bp sequence element derived from the enhancer-promoter of the human polyomavirus JCV. YB-1 and Purα are single-stranded DNA binding proteins which recognize C/T- and GC/GA-rich sequences, respectively. Results from band shift studies demonstrated that while both proteins interact directly with their DNA target sequences within the 23-bp motif, each protein can regulate the association of the other one with the DNA. Affinity chromatography and coimmunoprecipitation provide evidence for a direct interaction between Purα and YB-1 in the absence of the DNA sequence. Ectopic expression of YB-1 and Purα in glial cells synergistically stimulated viral promoter activity via the 23-bp sequence element. Results from mutational studies revealed that residues between amino acids 75 and 203 of YB-1 and between amino acids 85 and 215 of Purα are important for the interaction between these two proteins. Functional studies with glial cells indicated that the region within Purα which mediates its association with YB-1 and binding to the 23-bp sequence is important for the observed activation of the JCV promoter by the Purα and YB-1 proteins. The results of this study suggest that the cooperative interaction between YB-1 and Purα mediates the synergistic activation of the human polyomavirus JCV genome by these cellular proteins. The importance of these findings for cellular and viral genes which are regulated by Purα and YB-1 is discussed.

scholarly journals SF2/ASF binding region within JC virus NCCR limits early gene transcription in glial cells

2013 ◽  
Vol 10 (1) ◽  
pp. 147 ◽  
Author(s):  
Elena Uleri ◽  
Patrick Regan ◽  
Antonina Dolei ◽  
Ilker Sariyer
Keyword(s):  
Glial Cells ◽  
Gene Transcription ◽  
Jc Virus ◽  
Early Gene ◽  
Binding Region

Agnoprotein and its coding sequences play regulatory roles in JC virus gene transcription and replication in glial cells

2004 ◽  
Vol 10 (s2) ◽  
pp. 43-43
Author(s):  
M Safak ◽  
R Biffi ◽  
S Radhakrishnan ◽  
S Woolridge ◽  
I K Sariyer ◽  
...  
Keyword(s):  
Glial Cells ◽  
Gene Transcription ◽  
Jc Virus ◽  
Coding Sequences ◽  
Virus Gene ◽  
Transcription And Replication

scholarly journals Members of the AP-1 Family, c-Jun and c-Fos, Functionally Interact with JC Virus Early Regulatory Protein Large T Antigen

2003 ◽  
Vol 77 (9) ◽  
pp. 5241-5252 ◽  
Author(s):  
Joanne Kim ◽  
Stefanie Woolridge ◽  
Renato Biffi ◽  
Elisa Borghi ◽  
Adam Lassak ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Jc Virus ◽  
Regulatory Protein ◽  
T Antigen ◽  
Immediate Early ◽  
Human Polyomavirus ◽  
Viral Gene ◽  
Large T Antigen ◽  
Functional Interaction ◽  
Transcription And Replication

ABSTRACT The activating protein 1 (AP-1) family of regulatory proteins is characterized as immediate-early inducible transcription factors which were shown to be activated by a variety of stress-related stimuli and to be involved in numerous biological processes, including cellular and viral gene expression, cell proliferation, differentiation, and tumorigenesis. We have recently demonstrated the involvement of the AP-1 family members c-Jun and c-Fos in transcriptional regulation of the human polyomavirus, JC virus (JCV), genome. Here, we further examined their role in JCV gene regulation and replication through their physical and functional interaction with JCV early regulatory protein large T antigen (T-Ag). Transfection and replication studies indicated that c-Jun and c-Fos can significantly diminish T-Ag-mediated JCV gene transcription and replication. Affinity chromatography and coimmunoprecipitation assays demonstrated that c-Jun and T-Ag physically interact with each other. Results from band shift assays showed that the binding efficiency of c-Jun to the AP-1 site was reduced in the presence of T-Ag. In addition, we have mapped, through the use of a series of deletion mutants, the regions of these proteins which are important for their interaction. While the c-Jun interaction domain of T-Ag is localized to the middle portion of the protein, the T-Ag interacting domain of c-Jun maps to its basic-DNA binding region. Results of transient-transfection assays with various c-Jun mutants and T-Ag expression constructs further confirm the specificity of the functional interaction between c-Jun and T-Ag. Taken together, these data demonstrate that immediate-early inducible transcription factors c-Jun and c-Fos physically and functionally interact with JCV major early regulatory protein large T-Ag and that this interaction modulates JCV transcription and replication in glial cells.

scholarly journals Interaction of JC Virus Agno Protein with T Antigen Modulates Transcription and Replication of the Viral Genome in Glial Cells

2001 ◽  
Vol 75 (3) ◽  
pp. 1476-1486 ◽  
Author(s):  
Mahmut Safak ◽  
Robert Barrucco ◽  
Armine Darbinyan ◽  
Yuki Okada ◽  
Kazuo Nagashima ◽  
...  
Keyword(s):  
Dna Replication ◽  
Glial Cells ◽  
Viral Genome ◽  
Jc Virus ◽  
T Antigen ◽  
Lytic Cycle ◽  
Viral Gene ◽  
Deletion Mutants ◽  
Amino Terminal ◽  
Transcription And Replication

ABSTRACT In addition to encoding the structural and regulatory proteins, many viruses encode auxiliary proteins, some of which have been shown to play important roles in lytic and latent states of the viruses. The human neurotropic JC virus (JCV) genome encodes an auxiliary protein called Agno whose function remains unknown. Here, we investigated the functional role of JCV Agno protein on transcription and replication of the viral genome in glial cells. Results from transfection of human glial cells showed that Agno protein suppresses both T-antigen-mediated transcription of the viral late gene promoter and T-antigen-induced replication of viral DNA. Affinity chromatography and coimmunoprecipitation assays demonstrated that the Agno protein and T antigen physically interact with each other. Through the use of a series of deletion mutants, we demonstrated that the T-antigen-interacting region of Agno protein is localized to its amino-terminal half and the Agno-interacting domain of T antigen maps to its central portion. Furthermore, utilizing various Agno deletion mutants in functional studies, we confirmed the importance of the Agno-T antigen interaction in the observed down-modulation of T antigen function upon viral gene transcription and DNA replication by Agno protein. Taken together these data suggest that the Agno protein of JCV, which is produced late during the late phase of the lytic cycle, can physically and functionally interact with the viral early protein, T antigen, and downregulate viral gene expression and DNA replication. The importance of these observations in the lytic cycle of JCV is discussed.

scholarly journals Contrasting Roles of Endosomal pH and the Cytoskeleton in Infection of Human Glial Cells by JC Virus and Simian Virus 40

2003 ◽  
Vol 77 (2) ◽  
pp. 1347-1356 ◽  
Author(s):  
Aarthi Ashok ◽  
Walter J. Atwood
Keyword(s):  
Glial Cells ◽  
Intracellular Transport ◽  
Jc Virus ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Human Polyomavirus ◽  
Cellular Functions ◽  
Cytoplasmic Transport ◽  
Endosomal Ph ◽  
Sv40 Infection

ABSTRACT Infection of eukaryotic cells by pathogens requires the efficient use of host cell endocytic and cytoplasmic transport mechanisms. Understanding how these cellular functions are exploited by microorganisms allows us to better define the basic biology of pathogenesis while providing better insight into normal cellular functions. In this report we compare and contrast intracellular transport and trafficking of the human polyomavirus JC virus (JCV) with that of simian virus 40 (SV40). We have previously shown that infection of human glial cells by JCV requires clathrin-dependent endocytosis. In contrast, infection of cells by SV40 proceeds by caveola-dependent endocytosis. We now examine the roles of endosomal pH and the cellular cytoskeleton during infection of glial cells by both viruses. Our results demonstrate that JCV infection is sensitive to disruption of endosomal pH, whereas SV40 infection is pH independent. Infection by JCV is inhibited by treatment of glial cells with cytochalasin D, nocodazole, and acrylamide, whereas SV40 infection is affected only by nocodazole. These data point to critical differences between JCV and SV40 in terms of endocytosis and intracellular trafficking of their DNA genomes to the nucleus. These data also suggest a unique sequential involvement of cytoskeletal elements during infection of glial cells by JCV.

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