Acetylation of Histone H3 at the Nucleosome Dyad Alters DNA-Histone Binding

Histone post-translational modifications are essential for regulating and facilitating biological processes such as RNA transcription and DNA repair. Fifteen modifications are located in the DNA-histone dyad interface and include the acetylation of H3-K115 (H3-K115Ac) and H3-K122 (H3-K122Ac), but th...

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Bibliographic Details
Published in:The Journal of biological chemistry 2009-08, Vol.284 (35), p.23312-23321
Main Authors: Manohar, Mridula, Mooney, Alex M., North, Justin A., Nakkula, Robin J., Picking, Jonathan W., Edon, Annick, Fishel, Richard, Poirier, Michael G., Ottesen, Jennifer J.
Format: Article
Language:English
Subjects:
Acetylation
Animals
DNA - metabolism
DNA-Binding Proteins - chemistry
DNA-Binding Proteins - metabolism
Histones - chemical synthesis
Histones - chemistry
Histones - metabolism
Nucleosomes - chemistry
Nucleosomes - genetics
Nucleosomes - metabolism
Protein Binding
Transcription, Chromatin, and Epigenetics
Xenopus laevis
Xenopus Proteins - chemistry
Xenopus Proteins - metabolism
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Summary:Histone post-translational modifications are essential for regulating and facilitating biological processes such as RNA transcription and DNA repair. Fifteen modifications are located in the DNA-histone dyad interface and include the acetylation of H3-K115 (H3-K115Ac) and H3-K122 (H3-K122Ac), but the functional consequences of these modifications are unknown. We have prepared semisynthetic histone H3 acetylated at Lys-115 and/or Lys-122 by expressed protein ligation and incorporated them into single nucleosomes. Competitive reconstitution analysis demonstrated that the acetylation of H3-K115 and H3-K122 reduces the free energy of histone octamer binding. Restriction enzyme kinetic analysis suggests that these histone modifications do not alter DNA accessibility near the sites of modification. However, acetylation of H3-K122 increases the rate of thermal repositioning. Remarkably, Lys → Gln substitution mutations, which are used to mimic Lys acetylation, do not fully duplicate the effects of the H3-K115Ac or H3-K122Ac modifications. Our results are consistent with the conclusion that acetylation in the dyad interface reduces DNA-histone interaction(s), which may facilitate nucleosome repositioning and/or assembly/disassembly.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M109.003202