Differentiation-specific expression of chromatin remodeling factor BRM.

Area of Science:

• Molecular Biology
• Gene Regulation
• Chromatin Remodeling

Background:

• The SWI/SNF chromatin remodeling complex utilizes BRG1 or BRM as ATPase subunits.
• The specific physiological roles of these ATPase subunits remain unclear.
• Understanding the regulation of brm gene expression is crucial for elucidating its function.

Purpose of the Study:

• To investigate the developmental regulation of the brm gene.
• To identify transcription factors involved in brm gene expression control.
• To elucidate the mechanisms underlying brm gene's role in cell differentiation.

Main Methods:

• Analysis of brm gene expression during differentiation of P19, F9, and C2C12 cells.
• Reporter assays to assess brm promoter activity.
• Electrophoretic mobility shift assays (EMSAs) to study transcription factor binding.
• Mutagenesis of putative transcription factor binding sites in the brm promoter.

Main Results:

• BRM expression is specifically upregulated during the differentiation of various cell types, including neural cells and hepatocytes.
• The brm promoter contains binding sites for CCAAT enhancer binding protein beta (C/EBPbeta) and GATA factors (GATA2 and GATA3).
• C/EBPbeta stimulates brm promoter activity, while GATA2 and GATA3 down-regulate it. C/EBPbeta binds in differentiated cells, whereas GATAs bind in undifferentiated cells, suggesting mutually exclusive binding.

Conclusions:

• The brm gene is developmentally regulated and its expression is linked to cell differentiation.
• C/EBPbeta and GATA factors play opposing roles in regulating brm gene transcription.
• Mutually exclusive binding of C/EBPbeta and GATAs to overlapping promoter sites likely controls brm gene expression during development.