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TAFII55 binding to TAFII250 inhibits its acetyltransferase activity
A Gegonne1, J D Weissman, D S Singer
1Experimental Immunology Branch, Building 10, Room 4B-36, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Summary
The TFIID component TAF(II)55 binds to TAF(II)250, inhibiting its acetyltransferase activity. This interaction regulates MHC class I gene transcription, revealing a novel regulatory mechanism in gene expression.
Area of Science:
- Molecular Biology
- Gene Regulation
- Biochemistry
Background:
- General transcription factor TFIID is crucial for preinitiation complex assembly.
- TAF(II)250, a TFIID component, possesses acetyltransferase activity essential for MHC class I gene transcription.
Purpose of the Study:
- To identify cellular factors regulating TAF(II)250's acetyltransferase activity.
- To elucidate the mechanism by which TAF(II)55 affects TAF(II)250 function.
Main Methods:
- Yeast two-hybrid screening using a TAF(II)250 fragment.
- In vitro transcription assays with recombinant TAF(II)55.
Main Results:
- TAF(II)55 was identified as an interacting partner of TAF(II)250, binding to its RAP74-binding domain.
- TAF(II)55 binding inhibits TAF(II)250's acetyltransferase activity.
- Recombinant TAF(II)55 repressed TAF(II)250-dependent MHC class I transcription in vitro.
Conclusions:
- TAF(II)55 negatively regulates TAF(II)250's acetyltransferase activity.
- TAF(II)55 modulates TAF(II)250 function, impacting MHC class I gene transcription.