Acidic C-tail of HMGB1 is required for its target binding to nucleosome linker DNA and transcription stimulation.
HMGB1, a nonhistone chromosomal protein in higher eukaryotic nuclei, consists of two DNA binding motifs called HMG boxes and an acidic C-tail comprising a continuous array of 30 acidic amino acid residues. In the preceding study, we showed that the acidic C-tail of HMGB1 is required for transcription stimulation accompanied by chromatin decondensation in cultured cells. However, details of the involvement of the acidic C-tail in transcription stimulation were not clear. To clarify the mechanism of transcription stimulation by the acidic C-tail, we assessed the effect of the acidic C-tail on the transcription stimulation and nucleosome binding. Transcription stimulation assays using acidic C-tail deletion mutants showed that the five amino acid residues at the C-terminal end of HMGB1, a DDDDE sequence, are essential for the stimulation. The DDDDE sequence was also required for the preferential binding of HMGB1 to nucleosome linker DNA, which is a cognate HMGB1 binding site in chromatin. Cross-linking and far-Western experiments demonstrated that the DDDDE sequence interacts with the core histone H3 N-tail. These results strongly suggest that the interaction between the DDDDE sequence of HMGB1 and the H3 N-tail is a key factor for the transcription stimulation by HMGB1 as well as the preferential binding of HMGB1 to chromatin.
Department of Biological Science and Technology, Science University of Tokyo, Yamazaki, Noda-shi, Chiba 278-8510, Japan.
Tetsuya
T
Ueda
Hiroyasu
H
Chou
Toshifumi
T
Kawase
Hitoshi
H
Shirakawa
Michiteru
M
Yoshida
D000818:Animals; D001224:Aspartic Acid / Q000235:genetics; D001667:Binding, Competitive / Q000235:genetics; D019556:COS Cells; D002522:Chlorocebus aethiops; D004247:DNA / Q000378:metabolism*; D018698:Glutamic Acid / Q000235:genetics; D024243:HMGB1 Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D017384:Sequence Deletion; D015533:Transcriptional Activation; D014162:Transfection
D024243:HMGB1 Protein; D006657:Histones; D009707:Nucleosomes; D010446:Peptide Fragments; D001224:Aspartic Acid; D018698:Glutamic Acid; D004247:DNA