β-actin dependent chromatin remodeling mediates compartment level changes in 3D genome architecture

Area of Science:

• Molecular Biology
• Epigenetics
• Genomics

Background:

• Beta-actin is vital for chromatin remodeling complexes, including the mammalian Brahma-associated factor (BAF).
• BAF complexes regulate gene expression and counteract polycomb repressive complexes (PRCs).
• Previous studies linked beta-actin loss to altered gene expression and heterochromatin organization.

Purpose of the Study:

• To investigate if beta-actin levels directly impact the chromatin remodeling activities of BAF and polycomb proteins.
• To comprehensively analyze the genomic consequences of beta-actin knockout in mouse embryonic fibroblasts.

Main Methods:

• Genomic analysis of beta-actin knockout mouse embryonic fibroblasts (MEFs).
• Utilized ATAC-Seq, HiC-seq, RNA-Seq, and ChIP-Seq for epigenetic mark analysis.
• Assessed changes in chromatin structure, accessibility, and 3D genome architecture.

Main Results:

• Beta-actin levels modulate chromatin structure by influencing the interplay between BAF/BRG1 and EZH2.
• Changes in beta-actin affect local chromatin accessibility.
• Reversible alterations in 3D genome architecture were observed due to altered beta-actin levels and chromatin remodeling.

Conclusions:

• Beta-actin-dependent chromatin remodeling shapes the chromatin landscape.
• Beta-actin influences the regulation of genes critical for development and differentiation.
• Beta-actin plays a direct role in regulating chromatin accessibility and genome organization.