YY1 binds five cis-elements and trans-activates the myeloid cell-restricted gp91(phox) promoter

Area of Science:

• Molecular Biology
• Gene Regulation
• Cell Differentiation

Background:

• The gp91(phox) gene is crucial for myeloid cell function.
• Transcriptional regulation of gp91(phox) during differentiation is not fully understood.
• A protein complex, BID, binds to specific cis-elements in the gp91(phox) promoter.

Purpose of the Study:

• To identify the protein components of the BID complex.
• To elucidate the role of BID in gp91(phox) gene regulation during myeloid differentiation.
• To investigate the interaction between BID and the repressor CDP.

Main Methods:

• Ligand screening of an expression library using a gp91(phox) promoter binding site.
• Electrophoretic mobility shift assays (EMSAs) with YY1 antiserum.
• Transient co-transfection assays to assess promoter activity.

Main Results:

• The transcription factor YY1 was identified as a component of the BID complex.
• YY1 binds to multiple sites within the gp91(phox) promoter, including a newly identified site.
• Overexpression of YY1 activates a minimal gp91(phox) promoter, but YY1 levels do not change during differentiation.
• BID-binding activity is modulated by competition with the repressor CDP.

Conclusions:

• YY1 is a critical transcription factor for gp91(phox) expression in mature myeloid cells.
• YY1 function in myeloid development is regulated by the modulation of competing DNA-binding factors.
• This study reveals a mechanism for controlling gp91(phox) gene expression during myeloid differentiation.