Mapping and functional characterization of the TAF11 interaction with TFIIA

Area of Science:

• Molecular Biology
• Gene Regulation
• Protein-Protein Interactions

Background:

• Transcription Factor IIA (TFIIA) is essential for gene transcription, interacting with TFIID through TATA-binding protein (TBP) and TBP-associated factor 11 (TAF11).
• A previously identified mutation in TFIIA (toa2-I27K) impairs its interaction with TAF11, suggesting a functional link between these proteins.

Purpose of the Study:

• To investigate the functional relationship between TFIIA and TAF11.
• To identify compensatory mutations in TAF11 that restore function to a TFIIA mutant defective in TAF11 interaction.
• To elucidate the molecular mechanisms underlying the TAF11-TFIIA interaction and its role in gene expression.

Main Methods:

• Genetic screening to isolate compensatory TAF11 mutants.
• Analysis of TAF11 mutations to identify interaction regions.
• Phenotypic analysis of cells expressing altered TAF11 alleles.
• Biochemical assays to assess protein-DNA and protein-protein interactions.

Main Results:

• The interaction between TAF11 and TFIIA involves TAF11's histone fold domain and N-terminal region.
• TAF11 alleles defective for TFIIA interaction cause conditional growth defects and transcriptional impairment.
• TAF11 influences TFIIA-DNA and TBP-DNA contacts, enhancing TFIIA-TBP-DNA complex formation and stability.

Conclusions:

• The TAF11-TFIIA interaction is mediated by distinct regions of TAF11.
• This interaction plays a critical role in stabilizing transcription initiation complexes.
• The TAF11-TFIIA association is mechanistically important for regulating gene expression in vivo.