HTLV-1 basic leucine-zipper factor, HBZ, interacts with MafB and suppresses transcription through a Maf recognition element.

Takayuki Ohshima, Risa Mukai, Norie Nakahara, Jun Matsumoto, Osamu Isono, Yusuke Kobayashi, Satoru Takahashi, Kunitada Shimotohno

Faculty of Pharmaceutical Science at Kagawa Campus, Tokushima Bunri University, Kagawa, Japan. ohshimat@kph.bunri-u.ac.jp

Journal of cellular biochemistry 2010 Sep 1

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HTLV-1 infection causes adult T-cell leukemia (ATL). The development of ATL is thought to be associated with disruption of transcriptional control of cellular genes. HTLV-1 basic leucine-zipper (bZIP) factor, HBZ, is encoded by the complementary strand of the provirus. We previously reported that HBZ interacts with c-Jun and suppresses its transcriptional activity. To identify the cellular factor(s) that interact with HBZ, we conducted a yeast two-hybrid screen using full-length HBZ as bait and identified MafB. HBZ heterodimerizes with MafB via each bZIP domain. Luciferase analysis revealed a significant decrease in transcription through Maf recognition element (MARE) in a manner dependent on the bZIP domain of HBZ. Indeed, production of full-length HBZ in cells decreased the MARE-bound MafB protein, indicating that HBZ abrogates the DNA-binding activity of MafB. In addition, HBZ reduced the steady-state levels of MafB, and the levels were restored by treatment with a proteasome inhibitor. These results suggest a suppressive effect of HBZ on Maf function, which may have a significant role in HTLV-1 related pathogenesis. (c) 2010 Wiley-Liss, Inc.

Citation

Takayuki Ohshima, Risa Mukai, Norie Nakahara, Jun Matsumoto, Osamu Isono, Yusuke Kobayashi, Satoru Takahashi, Kunitada Shimotohno. HTLV-1 basic leucine-zipper factor, HBZ, interacts with MafB and suppresses transcription through a Maf recognition element. Journal of cellular biochemistry. 2010 Sep 1;111(1):187-94