scholarly journals JC virus promoter/enhancers contain TATA box-associated Spi-B-binding sites that support early viral gene expression in primary astrocytes

2012 ◽  
Vol 93 (3) ◽  
pp. 651-661 ◽  
Author(s):  
Leslie J. Marshall ◽  
Lisa D. Moore ◽  
Matthew M. Mirsky ◽  
Eugene O. Major
Keyword(s):  
Gene Expression ◽  
Binding Sites ◽  
Jc Virus ◽  
Viral Gene Expression ◽  
Antigen Expression ◽  
T Antigen ◽  
Viral Gene ◽  
Large T Antigen ◽  
Viral Promoter ◽  
The Brain

JC virus (JCV) is the aetiological agent of the demyelinating disease progressive multifocal leukoencephalopathy, an AIDS defining illness and serious complication of mAb therapies. Initial infection probably occurs in childhood. In the working model of dissemination, virus persists in the kidney and lymphoid tissues until immune suppression/modulation causes reactivation and trafficking to the brain where JCV replicates in oligodendrocytes. JCV infection is regulated through binding of host factors such as Spi-B to, and sequence variation in the non-coding control region (NCCR). Although NCCR sequences differ between sites of persistence and pathogenesis, evidence suggests that the virus that initiates infection in the brain disseminates via B-cells derived from latently infected haematopoietic precursors in the bone marrow. Spi-B binds adjacent to TATA boxes in the promoter/enhancer of the PML-associated JCV Mad-1 and Mad-4 viruses but not the non-pathogenic, kidney-associated archetype. The Spi-B-binding site of Mad-1/Mad-4 differs from that of archetype by a single nucleotide, AAAAGGGAAGGGA to AAAAGGGAAGGTA. Point mutation of the Mad-1 Spi-B site reduced early viral protein large T-antigen expression by up to fourfold. Strikingly, the reverse mutation in the archetype NCCR increased large T-antigen expression by 10-fold. Interestingly, Spi-B protein binds the NCCR sequence flanking the viral promoter/enhancer, but these sites are not essential for early viral gene expression. The effect of mutating Spi-B-binding sites within the JCV promoter/enhancer on early viral gene expression strongly suggests a role for Spi-B binding to the viral promoter/enhancer in the activation of early viral gene expression.

scholarly journals Novel Human Polyomavirus Noncoding Control Regions Differ in Bidirectional Gene Expression according to Host Cell, Large T-Antigen Expression, and Clinically Occurring Rearrangements

2018 ◽  
Vol 92 (7) ◽  
Author(s):  
Elvis T. Ajuh ◽  
Zongsong Wu ◽  
Emma Kraus ◽  
Fabian H. Weissbach ◽  
Tobias Bethge ◽  
...  
Keyword(s):  
Gene Expression ◽  
Host Cell ◽  
Binding Sites ◽  
T Antigen ◽  
Hek293 Cells ◽  
Human Polyomavirus ◽  
Gene Region ◽  
Viral Gene ◽  
Cell Tropism ◽  
Large T Antigen

ABSTRACTHuman polyomavirus (HPyV) DNA genomes contain three regions denoted the early viral gene region (EVGR), encoding the regulatory T-antigens and one microRNA, the late viral gene region (LVGR), encoding the structural Vp capsid proteins, and the noncoding control region (NCCR). The NCCR harbors the origin of viral genome replication and bidirectional promoter/enhancer functions governing EVGR and LVGR expression on opposite DNA strands. Despite principal similarities, HPyV NCCRs differ in length, sequence, and architecture. To functionally compare HPyV NCCRs, sequences from human isolates were inserted into a bidirectional reporter vector using dsRed2 for EVGR expression and green fluorescent protein (GFP) for LVGR expression. Transfecting HPyV NCCR reporter vectors into human embryonic kidney 293 (HEK293) cells and flow cytometry normalized to archetype BKPyV NCCR revealed a hierarchy of EVGR expression levels with MCPyV, HPyV12, and STLPyV NCCRs conferring stronger levels and HPyV6, HPyV9, and HPyV10 NCCRs weaker levels, while LVGR expression was less variable and showed comparable activity levels. Transfection of HEK293T cells expressing simian virus 40 (SV40) large T antigen (LTag) increased EVGR expression for most HPyV NCCRs, which correlated with the number of LTag-binding sites (Spearman'sr, 0.625;P< 0.05) and decreased following SV40 LTag small interfering RNA (siRNA) knockdown. LTag-dependent activation was specifically confirmed for two different MCPyV NCCRs in 293MCT cells expressing the cognate MCPyV LTag. HPyV NCCR expression in different cell lines derived from skin (A375), cervix (HeLaNT), lung (A549), brain (Hs683), and colon (SW480) demonstrated that host cell properties significantly modulate the baseline HPyV NCCR activity, which partly synergized with SV40 LTag expression. Clinically occurring NCCR sequence rearrangements of HPyV7 PITT-1 and -2 and HPyV9 UF1 were found to increase EVGR expression compared to the respective HPyV archetype, but this was partly host cell type specific.IMPORTANCEHPyV NCCRs integrate essential viral functions with respect to host cell specificity, persistence, viral replication, and disease. Here, we show that HPyV NCCRs not only differ in sequence length, number, and position of LTag- and common transcription factor-binding sites but also confer differences in bidirectional viral gene expression. Importantly, EVGR reporter expression was significantly modulated by LTag expression and by host cell properties. Clinical sequence variants of HPyV7 and HPyV9 NCCRs containing deletions and insertions were associated with increased EVGR expression, similar to BKPyV and JCPyV rearrangements, emphasizing that HPyV NCCR sequences are major determinants not only of host cell tropism but also of pathogenicity. These results will help to define secondary HPyV cell tropism beyond HPyV surface receptors, to identify key viral and host factors shaping the viral life cycle, and to develop preclinical models of HPyV persistence and replication and suitable antiviral targets.

scholarly journals Regulation of Gene Expression in Primate Polyomaviruses

2009 ◽  
Vol 83 (21) ◽  
pp. 10846-10856 ◽  
Author(s):  
Martyn K. White ◽  
Mahmut Safak ◽  
Kamel Khalili
Keyword(s):  
Gene Expression ◽  
Jc Virus ◽  
Regulation Of Gene Expression ◽  
T Antigen ◽  
Bk Virus ◽  
Viral Gene ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Karolinska Institute ◽  
Human Polyomaviruses

ABSTRACT Polyomaviruses are a growing family of small DNA viruses with a narrow tropism for both the host species and the cell type in which they productively replicate. Species host range may be constrained by requirements for precise molecular interactions between the viral T antigen, host replication proteins, including DNA polymerase, and the viral origin of replication, which are required for viral DNA replication. Cell type specificity involves, at least in part, transcription factors that are necessary for viral gene expression and restricted in their tissue distribution. In the case of the human polyomaviruses, BK virus (BKV) replication occurs in the tubular epithelial cells of the kidney, causing nephropathy in kidney allograft recipients, while JC virus (JCV) replication occurs in the glial cells of the central nervous system, where it causes progressive multifocal leukoencephalopathy. Three new human polyomaviruses have recently been discovered: MCV was found in Merkel cell carcinoma samples, while Karolinska Institute Virus and Washington University Virus were isolated from the respiratory tract. We discuss control mechanisms for gene expression in primate polyomaviruses, including simian vacuolating virus 40, BKV, and JCV. These mechanisms include not only modulation of promoter activities by transcription factor binding but also enhancer rearrangements, restriction of DNA methylation, alternate early mRNA splicing, cis-acting elements in the late mRNA leader sequence, and the production of viral microRNA.

scholarly journals CD4+ Lymphocyte-Mediated Suppression of Cytomegalovirus Expression in Human Astrocytes

2000 ◽  
Vol 7 (4) ◽  
pp. 710-713 ◽  
Author(s):  
Maxim C.-J. Cheeran ◽  
Genya Gekker ◽  
Shuxian Hu ◽  
Stephanie L. Yager ◽  
Phillip K. Peterson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Suppressive Activity ◽  
Soluble Factors ◽  
Human Astrocytes ◽  
Cd4 Lymphocyte ◽  
The Brain

ABSTRACT Cytomegalovirus-stimulated CD4+ lymphocytes from seropositive but not seronegative donors suppressed viral gene expression in primary human astrocytes. This suppressive activity was mediated through soluble factors. These findings suggest that CD4+ lymphocytes play a role in defense of the brain against cytomegalovirus.

scholarly journals An emerging and variant viral promoter of HIV-1 subtype C exhibits low-level gene expression noise

Retrovirology ◽  
2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Haider Ali ◽  
Disha Bhange ◽  
Kavita Mehta ◽  
Yuvrajsinh Gohil ◽  
Harshit Kumar Prajapati ◽  
...  
Keyword(s):  
Gene Expression ◽  
Binding Sites ◽  
High Throughput Screening ◽  
Cell Activation ◽  
Viral Gene ◽  
Viral Promoter ◽  
Gene Expression Noise ◽  
Low Level ◽  
Expression Noise ◽  
Hiv 1

Abstract Background We observe the emergence of several promoter-variant viral strains in India during recent years. The variant viral promoters contain additional copies of transcription factor binding sites present in the viral modulatory region or enhancer, including RBEIII, LEF-1, Ap-1 and/or NF-κB. These sites are crucial for governing viral gene expression and latency. Here, we infer that one variant viral promoter R2N3-LTR containing two copies of RBF-2 binding sites (an RBEIII site duplication) and three copies of NF-κB motifs may demonstrate low levels of gene expression noise as compared to the canonical RN3-LTR or a different variant R2N4-LTR (a duplication of an RBEIII site and an NF-κB motif). To demonstrate this, we constructed a panel of sub-genomic viral vectors of promoter-variant LTRs co-expressing two reporter proteins (mScarlet and Gaussia luciferase) under the dual-control of Tat and Rev. We established stable pools of CEM.NKR-CCR5 cells (CEM-CCR5RL reporter cells) and evaluated reporter gene expression under different conditions of cell activation. Results The R2N3-LTR established stringent latency that was highly resistant to reversal by potent cell activators such as TNF-α or PMA, or even to a cocktail of activators, compared to the canonical RN3- or the variant R2N4-LTR. The R2N3-LTR exhibited low-level basal gene expression in the absence of cell activation that enhanced marginally but significantly when activated. In the presence of Tat and Rev, trans-complemented in the form of an infectious virus, the R2N3-LTR demonstrated gene expression at levels comparable to the wild-type viral promoter. The R2N3-LTR is responsive to Tat and Rev factors derived from viral strains representing diverse genetic subtypes. Conclusion With extremely low-level transcriptional noise, the R2N3-LTR can serve as an excellent model to examine the establishment, maintenance, and reversal of HIV-1 latency. The R2N3-LTR would also be an ideal viral promoter to develop high-throughput screening assays to identify potent latency-reversing agents since the LTR is not affected by the usual background noise of the cell.

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 Renal cyst formation and multifocal neoplasia in transgenic mice carrying the simian virus 40 early region.

1991 ◽  
Vol 2 (1) ◽  
pp. 84-97
Author(s):  
K A Kelley ◽  
N Agarwal ◽  
S Reeders ◽  
K Herrup
Keyword(s):  
Transgenic Mice ◽  
Renal Cyst ◽  
Simian Virus 40 ◽  
Antigen Expression ◽  
Simian Virus ◽  
T Antigen ◽  
Tumor Formation ◽  
Large T Antigen ◽  
Early Region ◽  
The Brain

Simian virus 40 early region transgenic mice develop characteristic pathological abnormalities of the brain, kidney, and thymus, due to expression of large-T antigen. Earlier studies have indicated that the most consistent effect of large-T antigen expression is the formation of choroid plexus papillomas in the brain and that thymic hyperplasia and various kidney abnormalities are less frequently observed. The renal lesions reportedly consist of numerous glomerular abnormalities and tubular proliferation. Surprisingly, an analysis of 21 simian virus 40 early region transgenic mice, which were produced for this study, revealed a much higher incidence of polycystic kidney disease as well as earlier development of T-antigen-induced abnormalities. In marked contrast to earlier observations, there is an apparent reduction in the glomerular number in the affected kidneys, whereas the remaining glomeruli appear normal. The most striking feature of the T-antigen-induced renal abnormalities was extensive hyperplasia of tubular epithelial cells which was most marked in the distal tubules; all tubule segments are involved in the most severely affected animals. In most cases, cysts lined with hyperplastic epithelium were observed and papillary structures protruding from the cyst lining were evident. Multiple areas of focal neoplasia were apparent, and, in the most severely affected animals, there were areas in which tumor had replaced normal renal parenchyma. These results strongly suggest that T-antigen-induced renal cyst and tumor formation are part of the same pathological process which is initially manifested as tubular epithelial hyperplasia.

scholarly journals Suitability of hCMV for viral gene expression in the brain

2007 ◽  
Vol 4 (5) ◽  
pp. 379-379 ◽  
Author(s):  
Ian R Wickersham ◽  
Edward M Callaway
Keyword(s):  
Gene Expression ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
The Brain

scholarly journals Role of Notch Signal Transduction in Kaposi's Sarcoma-Associated Herpesvirus Gene Expression

2005 ◽  
Vol 79 (22) ◽  
pp. 14371-14382 ◽  
Author(s):  
Heesoon Chang ◽  
Dirk P. Dittmer ◽  
Shin-Young Chul ◽  
Youngkwon Hong ◽  
Jae U. Jung
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Transcription Factor ◽  
Binding Sites ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Lytic Gene ◽  
Lytic Gene Expression ◽  
Notch Signal

ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) RTA transcription factor is recruited to its responsive elements through interaction with a Notch-mediated transcription factor, RBP-Jκ, indicating that RTA mimics cellular Notch signal transduction to activate viral lytic gene expression. To test whether cellular Notch signal transduction and RTA are functionally exchangeable for viral gene expression, human Notch intracellular (hNIC) domain that constitutively activates RBP-Jκ transcription factor activity was expressed in KSHV-infected primary effusion lymphoma BCBL1 cells (TRExBCBL1-hNIC) in a tetracycline-inducible manner. Gene expression profiling showed that like RTA, hNIC robustly induced expression of a number of viral genes, including viral interleukin 6 (vIL-6), K3, and K5. Unlike RTA, however, hNIC was not capable of evoking the full repertoire of lytic viral gene expression and thereby lytic replication. To further understand the role of Notch signal transduction in KSHV gene expression, vIL-6 growth factor and K5 immune modulator genes were selected for detailed analysis. Despite the presence of multiple RBP-Jκ binding sites, hNIC targeted the specific RBP-Jκ binding sites of vIL-6 and K5 promoter regions to regulate their gene expression. These results indicate that cellular Notch signal transduction not only is partially exchangeable with RTA in regard to activation of viral lytic gene expression but also provides a novel expression profile of KSHV growth and immune deregulatory genes that is likely different from that of RTA-independent standard latency program as well as RTA-dependent lytic reproduction program.

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