Histone H1 enhances the DNA binding activity of the transcription factor EmBP-1.
Previous work indicated that nuclear extracts isolated from embryogenic rice suspension cells treated with the phytohormone abscisic acid (ABA) have enhanced binding activity to an ABA response element (Em1a) in the promoter of the Em gene from wheat. We identified an activity in wheat and maize nuclear extracts that enhances binding of the recombinant transcription factor EmBP-1 to Em1a by 80-fold. Fractionation of nuclear extracts led us to identify histone H1 and HMGb (but not HMGc or -d) as two factors that can enhance the ability of EmBP-1 to bind to Em1a and account for at least a part of this activity of nuclear extracts. Our results, which indicate for the first time that histone H1 possesses this type of activity, lend further support to the model that positively charged proteins can drastically affect the DNA binding activity of specific transcription factors. Furthermore, our study points to these chromosomal proteins as potential targets of an ABA-mediated modification (e.g. acetylation) that could affect the regulation of Em gene expression.
Schultz
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TF
Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA.
Spiker
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S
Quatrano
R S
RS
D050976:Basic-Leucine Zipper Transcription Factors; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006609:High Mobility Group Proteins / Q000378:metabolism; D006657:Histones / Q000494:pharmacology*; D016350:Leucine Zippers; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011479:Protamines / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C073988:Em protein, Triticum aestivum; D006609:High Mobility Group Proteins; D006657:Histones; D010940:Plant Proteins; D011479:Protamines; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D004247:DNA