scholarly journals Hepatitis B virus X protein transactivates human interleukin-8 gene through acting on nuclear factor kB and CCAAT/enhancer-binding protein-like cis-elements

1991 ◽  
Vol 266 (21) ◽  
pp. 13759-13763
Author(s):  
Y. Mahé ◽  
N. Mukaida ◽  
K. Kuno ◽  
M. Akiyama ◽  
N. Ikeda ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Binding Protein ◽  
Interleukin 8 ◽  
Nuclear Factor ◽  
Cis Elements ◽  
X Protein ◽  
Enhancer Binding Protein ◽  
B Virus ◽  
Nuclear Factor Kb

scholarly journals The Hepatitis B Virus X Protein Functionally Interacts with CREB-binding Protein/p300 in the Regulation of CREB-mediated Transcription

2006 ◽  
Vol 282 (7) ◽  
pp. 4277-4287 ◽  
Author(s):  
Delphine Cougot ◽  
Yuanfei Wu ◽  
Stefano Cairo ◽  
Julie Caramel ◽  
Claire-Angélique Renard ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Proliferating Cell Nuclear Antigen ◽  
Binding Protein ◽  
Interleukin 8 ◽  
Nuclear Antigen ◽  
Creb Binding Protein ◽  
X Protein ◽  
B Virus ◽  
Proliferating Cell

The hepatitis B virus infects more than 350 million people worldwide and is a leading cause of liver cancer. The virus encodes a multifunctional regulator, the hepatitis B virus X protein (HBx), that is essential for virus replication. HBx is involved in modulating signal transduction pathways and transcription mediated by various factors, notably CREB that requires the recruitment of the co-activators CREB-binding protein (CBP)/p300. Here we investigated the role of HBx and its potential interaction with CBP/p300 in regulating CREB transcriptional activity. We show that HBx and CBP/p300 synergistically enhanced CREB activity and that CREB phosphorylation by protein kinase A was a prerequisite for the cooperative action of HBx and CBP/p300. We further show that HBx interacted directly with CBP/p300 in vitro and in vivo. Using chromatin immunoprecipitation, we provide evidence that HBx physically occupied the CREB-binding domain of CREB-responsive promoters of endogenous cellular genes such as interleukin 8 and proliferating cell nuclear antigen. Moreover expression of HBx increased the recruitment of p300 to the interleukin 8 and proliferating cell nuclear antigen promoters in cells, and this is associated with increased gene expression. As recruitment of CBP/p300 is known to represent the limiting event for activating CREB target genes, HBx may disrupt this cellular regulation, thus predisposing cells to transformation.

scholarly journals RMP, a Novel RNA Polymerase II Subunit 5-Interacting Protein, Counteracts Transactivation by Hepatitis B Virus X Protein

1998 ◽  
Vol 18 (12) ◽  
pp. 7546-7555 ◽  
Author(s):  
Dorjbal Dorjsuren ◽  
Yong Lin ◽  
Wenxiang Wei ◽  
Tatsuya Yamashita ◽  
Takahiro Nomura ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Binding Protein ◽  
Host Protein ◽  
Dependent Manner ◽  
Binding Region ◽  
X Protein ◽  
B Virus

ABSTRACT To modulate transcription, regulatory factors communicate with basal transcription factors and/or RNA polymerases in a variety of ways. Previously, it has been reported that RNA polymerase II subunit 5 (RPB5) is one of the targets of hepatitis B virus X protein (HBx) and that both HBx and RPB5 specifically interact with general transcription factor IIB (TFIIB), implying that RPB5 is one of the communicating subunits of RNA polymerase II involved in transcriptional regulation. In this context, we screened for a host protein(s) that interacts with RPB5. By far-Western blot screening, we cloned a novel gene encoding a 508-amino-acid-residue RPB5-binding protein from a HepG2 cDNA library and designated it RPB5-mediating protein (RMP). Expression of RMP mRNA was detected ubiquitously in various tissues. Bacterially expressed recombinant RMP strongly bound RPB5 but neither HBx nor TATA-binding protein in vitro. Endogenous RMP was immunologically detected interacting with assembled RPB5 in RNA polymerase in mammalian cells. The central part of RMP is responsible for RPB5 binding, and the RMP-binding region covers both the TFIIB- and HBx-binding sites of RPB5. Overexpression of RMP, but not mutant RMP lacking the RPB5-binding region, inhibited HBx transactivation of reporters with different HBx-responsive cis elements in transiently transfected cells. The repression by RMP was counteracted by HBx in a dose-dependent manner. Furthermore, RMP has an inhibitory effect on transcriptional activation by VP16 in the absence of HBx. These results suggest that RMP negatively modulates RNA polymerase II function by binding to RPB5 and that HBx counteracts the negative role of RMP on transcription indirectly by interacting with RPB5.

scholarly journals Protein-x of hepatitis B virus in interaction with CCAAT/enhancer-binding protein α (C/EBPα) - an in silico analysis approach

2011 ◽  
Vol 8 (1) ◽  
pp. 41 ◽  
Author(s):  
Ashraf Mohamadkhani ◽  
Parisa Shahnazari ◽  
Zarrin Minuchehr ◽  
Armin Madadkar-Sobhani ◽  
Mahmoud Tehrani ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
In Silico ◽  
Binding Protein ◽  
In Silico Analysis ◽  
Analysis Approach ◽  
Enhancer Binding Protein ◽  
B Virus ◽  
Protein X ◽  
Silico Analysis

Hierarchic and cooperative binding of the rat liver nuclear protein C/EBP at the hepatitis B virus enhancer

1990 ◽  
Vol 10 (8) ◽  
pp. 4427-4430
Author(s):  
R Dikstein ◽  
O Faktor ◽  
Y Shaul
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Protein C ◽  
Binding Protein ◽  
Enhancer Activity ◽  
Low Concentrations ◽  
Enhancer Binding Protein ◽  
Target Dna ◽  
B Virus ◽  
A Site

We used the enhancer-binding protein C/EBP as a model to study the nature and the complexity of interaction of an enhancer-binding protein with its target DNA. We found that bacterially expressed C/EBP binds the hepatitis B virus enhancer at multiple sites in a hierarchic and cooperative manner. At low concentrations, only the E element is occupied, but at higher concentrations, additional sites are filled including a site that binds EP, a crucial enhancer-activating protein. This pattern of C/EBP binding may explain the concentration-dependent effect of C/EBP on enhancer activity.

scholarly journals The Hepatitis B Virus X Protein Binds to and Activates the NH2-Terminal trans-Activation Domain of Nuclear Factor of Activated T Cells-1

Virology ◽  
2002 ◽  
Vol 299 (2) ◽  
pp. 288-300 ◽  
Author(s):  
Marta Carretero ◽  
Marta Gómez-Gonzalo ◽  
Enrique Lara-Pezzi ◽  
Ignacio Benedicto ◽  
José Aramburu ◽  
...  
Keyword(s):  
T Cells ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Nuclear Factor ◽  
X Protein ◽  
Activation Domain ◽  
Activated T Cells ◽  
B Virus

scholarly journals GATA binding protein 4 promotes the expression and transcription of hepatitis B virus by facilitating hepatocyte nuclear factor 4 alpha in vitro

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Xiaoqin Lv ◽  
Xia Xiang ◽  
Yue Wu ◽  
Yang Liu ◽  
Ruqing Xu ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Binding Protein ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
B Virus ◽  
Hepatocyte Nuclear Factor 4 ◽  
Positive Effect

Abstract Background GATA binding protein 4 (GATA4) has been reported as a potential target of gene therapy for hepatocellular carcinoma (HCC). It is well known that the main cause of HCC is the chronic infection of hepatitis B virus (HBV). However, whether the effect of GATA4 on HBV has not yet been reported. Methods In this study, the regulation of GATA4 on HBV was analyzed in vitro. In turn, the effect of HBV on GATA4 was also observed in vitro, in vivo, and clinical HCC patients. Subsequently, we analyzed whether the effect of GATA4 on HBV was related to hepatocyte nuclear factor 4 alpha (HNF4α) in vitro. Results The results showed that GATA4 significantly promoted the secretion of HBV surface antigen (HBsAg) and HBV e antigen in the cell culture medium, improved the replication of HBV genomic DNA, and increased the level of HBV 3.5 kb pre-genomic RNA and HBV total RNA (P < 0.05). Moreover, it was showed that HBV had no significant effect on GATA4 in vitro and in vivo (P > 0.05). At the same time, GATA4 expression was decreased in 78.9% (15/19) of HCC patients regardless of the HBV and HBsAg status. Among them, there were 76.9% (10/13) in HBV-associated patients with HCC (HBV-HCC), and 83.3% (5/6) in non-HBV-HCC patients. In addition, the expression of HNF4α was also up-regulated or down-regulated accordingly when stimulating or interfering with the expression of GATA4. Furthermore, stimulating the expression of HNF4α could only alleviate the HBsAg level and HBV transcription levels, but had no significant effect on GATA4. Conclusions In summary, this study found that GATA4 has a positive effect on HBV, and the potential pathway may be related to another transcription factor HNF4α that regulates HBV.

scholarly journals Hierarchic and cooperative binding of the rat liver nuclear protein C/EBP at the hepatitis B virus enhancer.

1990 ◽  
Vol 10 (8) ◽  
pp. 4427-4430 ◽  
Author(s):  
R Dikstein ◽  
O Faktor ◽  
Y Shaul
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Protein C ◽  
Binding Protein ◽  
Enhancer Activity ◽  
Low Concentrations ◽  
Enhancer Binding Protein ◽  
Target Dna ◽  
B Virus ◽  
A Site

We used the enhancer-binding protein C/EBP as a model to study the nature and the complexity of interaction of an enhancer-binding protein with its target DNA. We found that bacterially expressed C/EBP binds the hepatitis B virus enhancer at multiple sites in a hierarchic and cooperative manner. At low concentrations, only the E element is occupied, but at higher concentrations, additional sites are filled including a site that binds EP, a crucial enhancer-activating protein. This pattern of C/EBP binding may explain the concentration-dependent effect of C/EBP on enhancer activity.

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