In vitro Nucleosome Assembly Facilitated by the Histone Chaperone SRCAP

Area of Science:

• Molecular Biology
• Epigenetics
• Chromatin Biology

Background:

• Nucleosomes, formed by DNA and histones, are fundamental units of eukaryotic chromosomes.
• Histone chaperones regulate nucleosome assembly, with Swr1 being crucial for H2A.Z-nucleosome formation.
• Micrococcal nuclease (MNase) digestion is a standard method for assessing nucleosome assembly.

Purpose of the Study:

• To present a straightforward and reproducible protocol for evaluating the histone chaperone activity of SRCAP (Snf2-related CREBBP activator protein).
• To facilitate the study of H2A.Z-nucleosome assembly dynamics.
• To provide a adaptable method for assessing other histone chaperones and regulatory factors.

Main Methods:

• Purification of a H2A.Z, H2B, and SRCAP complex using fast protein liquid chromatography (FPLC).
• In vitro assembly of the purified complex with DNA-(H3.1-H4^A15C)₂.
• Analysis of nucleosome formation using electrophoretic mobility shift assay (EMSA) and MNase digestion.

Main Results:

• A simple and reproducible protocol for analyzing SRCAP chaperone activity was established.
• The protocol successfully demonstrated in vitro nucleosome assembly facilitated by SRCAP.
• The method allows for the assessment of nucleosome formation using established biochemical assays.

Conclusions:

• The developed protocol offers a reliable method for studying SRCAP-mediated H2A.Z-nucleosome assembly.
• This approach can be adapted to investigate the function of other histone chaperones and regulatory proteins.
• The findings contribute to a better understanding of the molecular mechanisms governing nucleosome assembly.