scholarly journals Hepatitis B virus X protein up-regulates C4b-binding protein α through activating transcription factor Sp1 in protection of hepatoma cells from complement attack

Oncotarget ◽  
2016 ◽  
Vol 7 (19) ◽  
pp. 28013-28026 ◽  
Author(s):  
Guoxing Feng ◽  
Jiong Li ◽  
Minying Zheng ◽  
Zhe Yang ◽  
Yunxia Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Binding Protein ◽  
Hepatoma Cells ◽  
X Protein ◽  
Transcription Factor Sp1 ◽  
B Virus ◽  
Activating Transcription Factor

scholarly journals Hepatitis B virus X protein impedes the DNA repair via its association with transcription factor, TFIIH

2011 ◽  
Vol 11 (1) ◽  
pp. 48 ◽  
Author(s):  
Ishtiaq Qadri ◽  
Kaneez Fatima ◽  
Hany AbdeL-Hafiz
Keyword(s):  
Dna Repair ◽  
Transcription Factor ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
X Protein ◽  
B Virus

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.

Hepatitis B virus X protein upregulates expression of calpain small subunit 1 via nuclear facter-κB/p65 in hepatoma cells

2010 ◽  
Vol 82 (6) ◽  
pp. 920-928 ◽  
Author(s):  
Feng Zhang ◽  
Qi Wang ◽  
Lihong Ye ◽  
Yingming Feng ◽  
Xiaodong Zhang
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Small Subunit ◽  
Hepatoma Cells ◽  
X Protein ◽  
B Virus

Endoplasmic reticulum stress induced by hepatitis B virus X protein enhances cyclo-oxygenase 2 expression via activating transcription factor 4

2011 ◽  
Vol 435 (2) ◽  
pp. 431-439 ◽  
Author(s):  
Hyun Kook Cho ◽  
Kyu Jin Cheong ◽  
Hye Young Kim ◽  
JaeHun Cheong
Keyword(s):  
Endoplasmic Reticulum ◽  
Transcription Factor ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Critical Role ◽  
Activating Transcription Factor 4 ◽  
B Virus ◽  
Activating Transcription Factor ◽  
Transcription Factor 4 ◽  
Cox2 Expression

Chronic hepatitis B is a disease of the liver that can progress to cirrhosis and liver cancer. The HBx (hepatitis B virus X) protein of hepatitis B virus is a multifunctional regulator that induces ER (endoplasmic reticulum) stress by previously unknown mechanisms. ER stress plays a critical role in inflammatory induction and COX2 (cyclo-oxygenase 2) is an important mediator of this inflammation. In the present study, we demonstrate the molecular mechanisms of HBx on induction of ER stress and COX2 expression. In addition, HBx reduced expression of enzymes which are involved in mitochondrial β-oxidation of fatty acids and the mitochondrial inner membrane potential. The reduction in intracellular ATP levels by HBx induced the unfolded protein response and COX2 expression through the eIF2α (eukaryotic initiation factor 2α)/ATF4 (activating transcription factor 4) pathway. We confirmed that ATF4 binding to the COX2 promoter plays a critical role in HBx-mediated COX2 induction. The results of the present study suggest that HBV infection contributes to induction of hepatic inflammation through dysfunction of cellular organelles including the ER and mitochondria.

Hepatitis B virus X protein mutant HBxΔ127 promotes proliferation of hepatoma cells through up-regulating miR-215 targeting PTPRT

2014 ◽  
Vol 444 (2) ◽  
pp. 128-134 ◽  
Author(s):  
Fabao Liu ◽  
Xiaona You ◽  
Xiumei Chi ◽  
Tao Wang ◽  
Lihong Ye ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Hepatoma Cells ◽  
X Protein ◽  
B Virus

scholarly journals Hepatitis B Virus X Protein Is a Transcriptional Modulator That Communicates with Transcription Factor IIB and the RNA Polymerase II Subunit 5

1997 ◽  
Vol 272 (11) ◽  
pp. 7132-7139 ◽  
Author(s):  
Yong Lin ◽  
Takahiro Nomura ◽  
JaeHun Cheong ◽  
Dorjbal Dorjsuren ◽  
Katsuhira Iida ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
X Protein ◽  
Transcription Factor Iib ◽  
B Virus

scholarly journals Hepatitis B virus X protein modulates oncogene yes-associated protein by CREB to promote growth of hepatoma cells

Hepatology ◽  
2012 ◽  
Vol 56 (6) ◽  
pp. 2051-2059 ◽  
Author(s):  
Tao Zhang ◽  
Junping Zhang ◽  
Xiaona You ◽  
Qian Liu ◽  
Yumei Du ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Hepatoma Cells ◽  
X Protein ◽  
B Virus
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