Binding of the wheat basic leucine zipper protein EmBP-1 to nucleosomal binding sites is modulated by nucleosome positioning.
To investigate interactions of the basic leucine zipper transcription factor EmBP-1 with its recognition sites in nucleosomal DNA, we reconstituted an abscisic acid response element and a high-affinity binding site for EmBP-1 into human and wheat nucleosome cores in vitro. DNA binding studies demonstrated that nucleosomal elements can be bound by EmBP-1 at reduced affinities relative to naked DNA. EmBP-1 affinity was lowest when the recognition sites were positioned near the center of the nucleosome. Binding was achieved with a truncated DNA binding domain; however, binding of full-length EmBP-1 caused additional strong DNase I hypersensitivity flanking the binding sites. Similar results were observed with nucleosomes reconstituted with either human or wheat histones, demonstrating a conserved mechanism of transcription factor-nucleosome interactions. We conclude that positioning of recognition sequences on a nucleosome may play an important role in regulating interactions of EmBP-1 with its target sites in plant cells.
Niu
X
X
Department of Horticulture, Pennsylvania State University, University Park 16802, USA.
Adams
C C
CC
Workman
J L
JL
Guiltinan
M J
MJ
D000040:Abscisic Acid / Q000235:genetics; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003850:Deoxyribonuclease I; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D016350:Leucine Zippers / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014908:Triticum / Q000235:genetics / Q000378:metabolism*
D050976:Basic-Leucine Zipper Transcription Factors; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D009707:Nucleosomes; D010940:Plant Proteins; D014157:Transcription Factors; D000040:Abscisic Acid; D003850:Deoxyribonuclease I