A Method for Constructing Nucleosome Arrays with Spatially Defined Histone PTMs and DNA Damage

Area of Science:

• Molecular Biology
• Epigenetics
• DNA Repair

Background:

• Base excision repair (BER) is vital for genomic stability.
• Chromatin structure, particularly nucleosomes, hinders DNA accessibility for repair factors.
• The role of histone acetylation in globular domains on BER within nucleosome arrays is largely unknown.

Purpose of the Study:

• To investigate the impact of histone acetylation in globular domains on DNA repair efficiency within nucleosome arrays.
• To explore the spatial relationship between histone modifications and DNA damage sites in modulating repair.

Main Methods:

• Development of an abiotic/enzymatic hybrid catalyst system (ABEHCS) for regioselective histone acetylation.
• Utilized a plug-and-play strategy to introduce specific DNA damage (deoxycytidine-to-deoxyuridine).
• Constructed nucleosome arrays with controlled configurations of histone acetylation and DNA lesions.

Main Results:

• H3K56 acetylation in the histone globular domain was found to enhance BER efficiency.
• The enhancement of BER was mediated by uracil-DNA glycosylase (UDG) and apurinic/apyrimidinic endonuclease 1 (APE1).
• The efficiency of BER was dependent on the spatial proximity between H3K56 acetylation and the DNA damage site.

Conclusions:

• Histone acetylation within the globular domain of histones can positively regulate DNA repair.
• The spatial arrangement of epigenetic marks and DNA lesions is a critical determinant of repair pathway efficacy.
• Findings provide insights into the mechanisms of DNA repair in the context of chromatin organization.