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TFIIA induces conformational changes in TFIID via interactions with the basic repeat.
D K Lee1, J DeJong, S Hashimoto
1Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10021.
Molecular and Cellular Biology
|November 1, 1992
Summary
Transcription factor IIA (TFIIA) enhances transcription factor II D (TFIID) binding to DNA by overcoming inhibitory effects from TFIID's N terminus. This interaction may enable TFIID to recognize diverse promoter sequences.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Transcription initiation in eukaryotes involves complex protein-DNA interactions.
- TFIID (Transcription Factor II D) is a crucial initiator of transcription.
- TFIIA (Transcription Factor II A) is known to interact with TFIID.
Purpose of the Study:
- To elucidate the mechanism by which TFIIA influences TFIID's DNA binding.
- To investigate the role of TFIID's N terminus in TFIIA-mediated regulation.
- To determine if TFIIA affects TFIID's promoter specificity.
Main Methods:
- Site-directed mutagenesis of Saccharomyces cerevisiae TFIID.
- DNA-binding assays using purified TFIID and TFIIA.
- Analysis of TFIID-DNA interactions with TATA-containing probes.
Main Results:
- TFIIA interacts with TFIID's basic repeat region, inducing structural changes.
- TFIIA compensates for TFIID mutations that impair DNA binding.
- TFIIA binding to TFIID becomes temperature-independent, mimicking N-terminal truncation.
- TFIIA reduces the influence of flanking DNA sequences on TFIID binding.
Conclusions:
- TFIIA enhances TFIID DNA binding by negating inhibitory effects of TFIID's nonconserved N terminus.
- TFIIA may broaden the range of promoters recognized by TFIID by reducing sensitivity to flanking sequences.