TFIIB Recognition Elements Control the TFIIA-NC2 Axis in Transcriptional Regulation

Abstract

TFIIB recognizes DNA sequence-specific motifs that can flank the TATA elements of the promoters of protein-encoding genes. The TFIIB recognition elements (BRE^u and BRE^d) can have positive or negative effects on transcription in a promoter context-dependent manner. Here we show that the BREs direct the selective recruitment of TFIIA and NC2 to the promoter. We find that TFIIA preferentially associates with BRE-containing promoters while NC2 is recruited to promoters that lack consensus BREs. The functional relevance of the BRE-dependent recruitment of TFIIA and NC2 was determined by small interfering RNA-mediated knockdown of TFIIA and NC2, both of which elicited BRE-dependent effects on transcription. Our results confirm the established functional reciprocity of TFIIA and NC2. However, our findings show that TFIIA assembly at BRE-containing promoters results in reduced transcriptional activity, while NC2 acts as a positive factor at promoters that lack functional BREs. Taken together, our results provide a basis for the selective recruitment of TFIIA and NC2 to the promoter and give new insights into the functional relationship between core promoter elements and general transcription factor activity.

SUPPLEMENTAL MATERIAL

Supplemental material for this article may be found at http://mcb.asm.org/ .

ACKNOWLEDGMENTS

We thank Bob White and members of the Oelgeschläger and Roberts labs for comments on the manuscript. We also thank Daniel Haber for the podocalyxin promoter reporter, Andrew Ward for the IGFII promoter reporter, Neil Perkins for the BCL2/p21 promoter reporters, Andy Sharrocks for the Egr1 promoter reporter, and Stephen Taylor for help with the Flp-In system.

This work was funded by the Wellcome Trust (061207/Z/00/Z/CH/TG/dr). S.G.E.R. is a Wellcome Trust Senior Research Fellow.

The authors have no competing financial interests.