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Site-specific cross-linking of TBP in vivo and in vitro reveals a direct functional interaction with the SAGA subunit Spt3

Authors :
Steven Hahn
Neeman Mohibullah
Source :
Genes & Development. 22:2994-3006
Publication Year :
2008
Publisher :
Cold Spring Harbor Laboratory, 2008.

Abstract

The TATA-binding protein (TBP) is critical for transcription by all three nuclear RNA polymerases. In order to identify factors that interact with TBP, the nonnatural photoreactive amino acid ρ-benzoyl-phenylalanine (BPA) was substituted onto the surface of Saccharomyces cerevisiae TBP in vivo. Cross-linking of these TBP derivatives in isolated transcription preinitiation complexes or in living cells reveals physical interactions of TBP with transcriptional coregulator subunits and with the general transcription factor TFIIA. Importantly, the results show a direct interaction between TBP and the SAGA coactivator subunits Spt3 and Spt8. Mutations on the Spt3-interacting surface of TBP significantly reduce the interaction of TBP with SAGA, show a corresponding decrease in transcription activation, and fail to recruit TBP to a SAGA-dependent promoter, demonstrating that the direct interaction of these factors is important for activated transcription. These results prove a key prediction of the model for stimulation of transcription at SAGA-dependent genes via Spt3. Our cross-linking data also significantly extend the known surfaces of TBP that directly interact with the transcriptional regulator Mot1 and the general transcription factor TFIIA.

Details

ISSN :
15495477 and 08909369
Volume :
22
Database :
OpenAIRE
Journal :
Genes & Development
Accession number :
edsair.doi.dedup.....33560ce66bc86d5f472822a62c7006cb
Full Text :
https://doi.org/10.1101/gad.1724408