Adenovirus E1A proteins interact with the cellular YY1 transcription factor

Area of Science:

• Molecular Biology
• Virology
• Gene Regulation

Background:

• Adenovirus E1A proteins are known to modulate cellular transcription.
• The cellular transcription factor YY1 can repress gene expression.
• Previous studies suggest E1A proteins can relieve YY1-mediated repression.

Purpose of the Study:

• To investigate the interaction between adenovirus E1A proteins and the transcription factor YY1.
• To identify the domains involved in E1A-YY1 binding and functional consequences.
• To elucidate the mechanism by which E1A relieves YY1-mediated transcriptional repression.

Main Methods:

• In vivo and in vitro binding assays to assess E1A-YY1 interaction.
• Site-directed mutagenesis to map interaction domains on E1A and YY1.
• Reporter gene assays to evaluate transcriptional activity and repression relief.
• Cotransfection experiments using GAL4-YY1 fusion proteins.

Main Results:

• Both 12S and 13S E1A proteins bind to YY1, with 13S E1A showing higher affinity.
• Specific domains on E1A (N-terminal and CR3) and YY1 (residues 54-260 and C-terminal 332-414) mediate the interaction.
• E1A interaction with the YY1 C-terminal domain correlates with relief of repression.
• E1A proteins can relieve repression mediated by the carboxy-terminal domain of YY1.

Conclusions:

• Adenovirus E1A proteins directly bind to the transcription factor YY1.
• The interaction involves specific domains on both E1A and YY1 proteins.
• E1A proteins relieve YY1-mediated transcriptional repression, at least in part, through direct binding to YY1.