Purification of multiprotein histone acetyltransferase complexes.

Area of Science:

• Molecular Biology
• Epigenetics
• Gene Regulation

Background:

• Histone acetylation, regulated by histone acetyltransferases (HATs), is crucial for eukaryotic gene transcription.
• While recombinant HATs show activity in vitro, their function on physiological substrates like nucleosomes is often limited.
• HATs function within large, multi-subunit complexes in vivo, and associated proteins modulate their activity and substrate specificity.

Purpose of the Study:

• To describe efficient methods for purifying large, multi-protein HAT complexes from mammalian nuclear extracts.
• To enable the study of HAT complexes with their physiological substrates in vitro.
• To provide a model for understanding how HAT complex composition affects catalytic activity and substrate targeting.

Main Methods:

• Generation and large-scale suspension culture of mammalian epitope-tagged cell lines.
• Rapid, two-step purification of multi-protein HAT complexes from nuclear extracts.
• Characterization of purified HAT complexes for activity on physiological substrates.

Main Results:

• Successful purification of large, multi-protein HAT complexes using the described methods.
• Purified HAT complexes, including human GCN5 complexes, retained activity on physiological substrates in vitro.
• The methods allow for the isolation of functional HAT complexes that better mimic their in vivo state.

Conclusions:

• The developed purification strategy provides functional HAT complexes for in vitro studies.
• This approach facilitates the investigation of HAT complex regulation and substrate interactions.
• These methods offer a valuable tool for understanding the role of HAT complexes in gene transcription.