HMGB Proteins and Transcriptional Regulation

In eukaryotic nuclei, transcription reactions on the chromatin are regulated by the binding of transcription regulators such as transcription factors and chromatin remodeling factors to chromatin. High-mobility-group-box (HMGB) protein family is a member of HMG super family proteins, the most abundant and ubiquitous non-histone chromatin binding proteins in eukaryotic cells. HMGB proteins bind to chromosomal DNA via their DNA binding motif, a HMG box, and induce structural changes of chromatin. Besides the chromatin binding property of HMGB proteins, HMGB proteins also interact with other proteins including transcription regulators and histones. In addition to those key transcriptional regulatory proteins, undoubtedly HMGB proteins bind dynamically to chromatin and interact with other proteins including transcription factors, thereby participating in transcription regulation in multiple processes. We will focus on the transcription regulation by HMGB proteins bound to chromatin, and possible roles of the unique structural and functional domain, the acidic C-tail region.