Specific interactions and potential functions of human TAFII100

Area of Science:

• Molecular Biology
• Gene Regulation
• Protein Biochemistry

Background:

• Human transcription initiation factor TFIID is crucial for gene expression.
• TFIID comprises the TATA-binding protein (TBP) and TBP-associated factors (TAFs).
• Understanding TFIID's subunit organization and function is key to deciphering transcription regulation.

Purpose of the Study:

• To investigate the structural organization and functional role of the human TFIID subunit, hTAFII100.
• To determine hTAFII100's interactions with other TFIID components.
• To assess hTAFII100's contribution to basal transcription, particularly at different core promoter types.

Main Methods:

• Cloning and expression of the DNA encoding hTAFII100.
• Immunoprecipitation studies to identify interacting TFIID subunits.
• In vivo and in vitro assays to map protein interaction domains.
• Functional assays using anti-hTAFII100 antibodies to assess effects on transcription.

Main Results:

• hTAFII100 is an integral TFIID subunit associated with transcriptionally active forms.
• The N-terminal region of hTAFII100 is surface-exposed, while the C-terminal WD-40 repeats are inaccessible.
• hTAFII100 strongly interacts with histone-like TAFs (hTAFII80 and hTAFII31) and weakly with other TAFs and TBP.
• Anti-hTAFII100 antibodies selectively inhibit transcription from TATA-less promoters.

Conclusions:

• hTAFII100 plays a significant role in stabilizing TFIID complex interactions, especially with histone-like TAFs.
• hTAFII100 exhibits a potential core promoter-specific function, influencing basal transcription initiation.
• These findings provide insights into the structural and functional intricacies of the TFIID transcription factor.