Basic and Acidic Regions Flanking the HMG-Box Domain of Maize HMGB1 and HMGB5 Modulate the Stimulatory Effect on the DNA Binding of Transcription Factor Dof2

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• 作者：Marion Grasser ; Julia M. Christensen ; Christoph Peterh&auml ; nsel ; Klaus D. Grasser
• 刊名：Biochemistry
• 出版年：2007
• 出版时间：May 29, 2007
• 年：2007
• 卷：46
• 期：21
• 页码：6375 - 6382
• 全文大小：431K
• 年卷期：v.46,no.21(May 29, 2007)
• ISSN：1520-4995

文摘

The chromatin-associated high-mobility group (HMG) proteins of the plant HMGB familyare characterized by a central HMG-box domain that is flanked by a basic N-terminal and an acidicC-terminal domain. By functional interaction with certain transcription factors, HMGB proteins contributeto transcriptional regulation. Previous work has shown that the maize HMGB5 protein is markedly moreefficient than other HMGB proteins in stimulating the binding of transcription factor Dof2 to DNA targetsites. Here we examine the structural requirements that determine the particular efficiency of HMGB5.The HMG-box domains of HMGB1 and HMGB5 (which mediate the interaction with Dof2) promotedDof2-DNA binding to a similar extent, indicating that the terminal domains modulate the interactionwith Dof2. Analysis of full-length, truncated, and chimeric HMGB1/5 proteins revealed that the acidicC-terminal domains positively influence the stimulation of Dof2-DNA binding, while the basic N-terminaldomains have a rather negative effect. In particular, the C-terminal domain of HMGB5 has a strikingpositive effect and may account for the efficient stimulation mediated by full-length HMGB5. Interestingly,recombinant HMGB protein variants that have a relatively low affinity for linear DNA (such as proteinslacking the basic N-terminal domain) efficiently assist Dof2-DNA binding.