The Nucleosome Remodeling and Deacetylase Complex NuRD Is Built from Preformed Catalytically Active Sub-modules

Area of Science:

• Chromatin biology
• Molecular mechanisms of gene regulation
• Protein complex assembly

Background:

• The nucleosome remodeling deacetylase (NuRD) complex is a crucial regulator of chromatin structure and gene transcription.
• While the structure of NuRD and other chromatin modifiers is known, their assembly process and the existence of stable, active sub-modules remain unclear.
• Understanding NuRD assembly is key to deciphering its regulatory roles.

Purpose of the Study:

• To investigate the assembly pathway and functional sub-modules of the NuRD complex.
• To determine if NuRD sub-modules retain enzymatic activity independently.
• To visualize the in vivo association of NuRD sub-modules in live cells.

Main Methods:

• Purification of endogenous Drosophila NuRD complex.
• Systematic production of NuRD component combinations using the MultiBac system.
• Biophysical characterization and enzymatic activity assays.
• Single-molecule imaging of CHD4 in live mouse embryonic stem cells.

Main Results:

• The Drosophila NuRD complex comprises a stable core and transiently associated subunits like CHD4.
• Experimentally produced NuRD sub-modules retained enzymatic activity and exhibited distinct biophysical properties.
• In vivo imaging demonstrated the association of core deacetylase and chromatin-remodeling sub-modules.

Conclusions:

• NuRD likely assembles through preformed, enzymatically active sub-modules.
• These active sub-modules are found in both nuclear and cytosolic compartments.
• This assembly pathway has significant implications for understanding NuRD's diverse functions in gene regulation.