Binding of Histone H1 to DNA Is Indifferent to Methylation at CpG Sequences (*)
- From the Institute of Cell and Molecular Biology, University of Edinburgh, Kings Buildings, Edinburgh EH9 3JR, United Kingdom
- § To whom correspondence should be addressed. Tel.: 44-131-650-5670; Fax: 44-131-650-5379.
Abstract
The possibility that histone H1 binds preferentially to DNA containing 5-methylcytosine in the dinucleotide CpG is appealing, as it could help to explain the repressive effects of methylation on gene activity. In this study, the affinity of purified H1 for methylated and non-methylated DNA sequences has been tested using both naked DNA and chromatin. Based on a variety of assays (bandshifts, filter-binding assays, Southwestern blots, and nuclease sensitivity assays), we conclude that H1 has no significant preference for binding to naked methylated DNA. Similarly, H1 showed the same affinities for methylated and non-methylated DNA when assembled into chromatin in a Xenopus oocyte extract. Thus potential cooperative interaction of H1 with polynucleosomal complexes is not enhanced by the presence of DNA methylation.
Footnotes
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↵* This work was supported by the Imperial Cancer Research Fund, The Wellcome Trust, the Howard Hughes Medical Institute, and the Human Capital and Mobility Programme of the European Community. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵1 The abbreviations used are:
- MeCP
-
methyl-CpG binding protein
- bp
-
base pair(s)
- MDBP
-
methylated DNA-binding protein
- DTT
-
dithiothreitol
- BSA
-
bovine serum albumin
- kb
-
kilobase(s).
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- Received July 12, 1995.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
