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Human hepatitis B virus X protein augments the DNA binding of nuclear factor for IL‐6 through its basic‐leucine zipper domain
Author(s) -
Ohno Hideki,
Kaneko Shuichi,
Lin Yong,
Kobayashi Kenichi,
Murakami Seishi
Publication year - 1999
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/(sici)1096-9071(199905)58:1<11::aid-jmv2>3.0.co;2-h
Subject(s) - leucine zipper , hbx , microbiology and biotechnology , biology , dna binding domain , binding site , binding domain , bzip domain , recombinant dna , dna binding protein , promoter , dna , gene , transcription factor , biochemistry , gene expression , transfection
The X gene product of human hepatitis B virus, HBx, transactivates the expression of viral and cellular genes through a wide variety of cis elements, including the nuclear factor for IL‐6 (NF‐IL6) binding sites, although HBx does not appear to bind DNA directly. We previously reported that HBx transactivated the interleukin 8 promoter through NF‐κB binding site and C/EBP‐like binding site (NF‐IL6 binding site). In this study, the interactions were examined between NF‐IL6 and HBx using recombinant proteins. In a DNA‐protein binding assay, the formation of a specific complex between NF‐IL6 and a DNA probe harboring an NF‐IL6 binding site was increased by the addition of either the full or the C‐terminal 104 amino acids of HBx. A direct protein‐protein binding assay (far‐Western blot) revealed the direct interaction between the C‐terminal 104 amino acids of HBx and the basic region‐leucine zipper domain of NF‐IL6. These results indicate that HBx alters the DNA‐binding affinity of NF‐IL6 through the direct interaction between the C‐terminal domain of HBx and the basic region‐leucine zipper domain of NF‐IL6. J. Med. Virol. 58:11–18, 1999. © 1999 Wiley‐Liss, Inc.