Publications (2)14.68 Total impact
-
Article: Effects of histone acetylation by Piccolo NuA4 on the structure of a nucleosome and the interactions between two nucleosomes.
[show abstract] [hide abstract]
ABSTRACT: We characterized the effect of histone acetylation on the structure of a nucleosome and the interactions between two nucleosomes. In this study, nucleosomes reconstituted with the Selex "Widom 601" sequence were acetylated with the Piccolo NuA4 complex, which acetylates mainly H4 N-terminal tail lysine residues and some H2A/H3 N-terminal tail lysine residues. Upon the acetylation, we observed directional unwrapping of nucleosomal DNA that accompanies topology change of the DNA. Interactions between two nucleosomes in solution were also monitored to discover multiple transient dinucleosomal states that can be categorized to short-lived and long-lived (∼1 s) states. The formation of dinucleosomes is strongly Mg(2+)-dependent, and unacetylated nucleosomes favor the formation of long-lived dinucleosomes 4-fold as much as the acetylated ones. These results suggest that the acetylation of histones by Piccolo NuA4 disturbs not only the structure of a nucleosome but also the interactions between two nucleosomes. Lastly, we suggest a structural model for a stable dinucleosomal state where the two nucleosomes are separated by ∼2 nm face-to-face and rotated by 34° with respect to each other.Journal of Biological Chemistry 01/2011; 286(13):11099-109. · 4.77 Impact Factor -
Article: DNA methylation increases nucleosome compaction and rigidity.
[show abstract] [hide abstract]
ABSTRACT: Cytosine methylation on CpG dinucleotides is an essential epigenetic modification in eukaryotes. How DNA methylation modulates nucleosome structure and dynamics has been a long-standing question. We implemented a single-molecule method to monitor the effects of DNA methylation on the structure and dynamics of mononucleosomes. Our studies show that DNA methylation induces a more compact and rigid nucleosome structure, providing a physical basis for how DNA methylation might contribute to regulating chromatin structure.Journal of the American Chemical Society 02/2010; 132(6):1782-3. · 9.91 Impact Factor
