Taf2 mediates DNA binding of Taf14

Area of Science:

• Molecular biology
• Structural biology
• Yeast genetics

Background:

• The yeast general transcription factor TFIID complex is crucial for gene transcription.
• Specific interactions between Taf14 and Taf2 subunits are necessary for TFIID assembly and function.
• The precise mechanism of Taf14-Taf2 interaction and its role in transcription remain poorly understood.

Purpose of the Study:

• To elucidate the molecular and structural basis of Taf14 and Taf2 subunit interactions within the yeast TFIID complex.
• To investigate the DNA-binding activity of the Taf14 subunit and its regulation.
• To determine the functional significance of Taf14-Taf2 interaction and Taf14 DNA binding in vivo.

Main Methods:

• X-ray crystallography to determine the structure of Taf14 domains bound to Taf2.
• Biochemical assays to assess DNA-binding activity of Taf14.
• Site-directed mutagenesis to investigate the role of specific domains.
• Genetic analysis in yeast to evaluate the in vivo function.

Main Results:

• The YEATS and ET domains of Taf14 bind to the C-terminal tail of Taf2.
• A unique DNA-binding activity was identified in the linker region of Taf14.
• Taf14's DNA-binding is autoinhibited in the absence of ligands.
• Taf2 binding induces a conformational change in Taf14, releasing the linker for DNA and nucleosome engagement.
• In vivo, the association of Taf14 with Taf2 and DNA is essential for transcriptional regulation.

Conclusions:

• The interaction between Taf14 and Taf2 is regulated by conformational changes.
• Taf2 binding activates Taf14's DNA-binding capability, facilitating transcription.
• This study provides a structural and mechanistic basis for understanding TFIID function in yeast transcription.