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Nucleosome recognition by the Piccolo NuA4 histone acetyltransferase complex
Christopher E Berndsen1, William Selleck, Steven J McBryant
1Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin 53706, USA.
Biochemistry
|February 6, 2007
Summary
Histone acetyltransferase (HAT) complexes like Piccolo NuA4 bind nucleosomes via histone-fold domains, not tails. This mechanism enables efficient H4 tail acetylation, revealing key insights into epigenetic regulation.
Area of Science:
- Biochemistry
- Epigenetics
- Molecular Biology
Background:
- Multisubunit histone acetyltransferase (HAT) complexes play crucial roles in gene regulation.
- Understanding how these HAT complexes recognize nucleosome substrates is essential for elucidating epigenetic mechanisms.
Purpose of the Study:
- To determine the critical components of nucleosome recognition by the Piccolo NuA4 (picNuA4) HAT complex.
- To investigate the role of histone tails and histone-fold domains in nucleosome binding and acetylation.
Main Methods:
- Biochemical approaches were employed to analyze substrate recognition.
- Histone-based substrates of increasing complexity were compared.
Main Results:
- Histone tails are dispensable for picNuA4 binding to nucleosomes and free histones.
- The histone-fold domain (HFD) regions, particularly H4 residues 21-52, are critical for tight binding and efficient tail acetylation.
- picNuA4 recognizes the nucleosome surface where the H4 HFD is located, tethering the enzyme for successive acetylation cycles.
Conclusions:
- Nucleosome recognition by picNuA4 relies on the histone-fold domain, specifically the H4 HFD.
- This binding mechanism facilitates efficient acetylation of histone H4 and H2A tails, impacting epigenetic regulation.
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