title: DNA methylation-dependent chromatin fiber compaction in vivo and in vitro: requirement for linker histone.
abstract: Dynamic alterations in chromatin structure mediated by postsynthetic histone modifications and DNA methylation constitute a major regulatory mechanism in DNA functioning. DNA methylation has been implicated in transcriptional silencing, in part by inducing chromatin condensation. To understand the methylation-dependent chromatin structure, we performed atomic force microscope (AFM) studies of fibers isolated from cultured cells containing normal or elevated levels of m5C. Chromatin fibers were reconstituted on control or methylated DNA templates in the presence or absence of linker histone. Visual inspection of AFM images, combined with quantitative analysis of fiber structural parameters, suggested that DNA methylation induced fiber compaction only in the presence of linker histones. This conclusion was further substantiated by biochemical results.
authors.affiliation: Physical Molecular Biology, Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-5055, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Karymov
authors.forename: M
authors.initials: M
authors.lastname: Tomschik
authors.forename: S H
authors.initials: SH
authors.lastname: Leuba
authors.forename: P
authors.initials: P
authors.lastname: Caiafa
authors.forename: J
authors.initials: J
authors.lastname: Zlatanova
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002499:Centrifugation, Density Gradient; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D003596:Cytosine / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D013698:Templates, Genetic
chemical_list: D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D003596:Cytosine; D004247:DNA