Human hepatitis B virus X protein augments the DNA binding of nuclear factor for IL-6 through its basic-leucine zipper domain
✍ Scribed by Ohno, Hideki; Kaneko, Shuichi; Lin, Yong; Kobayashi, Kenichi; Murakami, Seishi
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 805 KB
- Volume
- 58
- Category
- Article
- ISSN
- 0146-6615
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✦ Synopsis
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-B 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 DNAprotein 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 regionleucine zipper domain of NF-IL6.