Xiao-Yong Li, Sukesh R. Bhaumik, Xiaocun Zhu, Lei Li, Wu-Cheng Shen, Bharat L. Dixit, and Michael R. Green
Howard Hughes Medical Institute, Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605 USA
Correspondence: Michael R. Green: (508) 856-5331 (phone);
(508) 856-5473 (fax)
michael.green@umassmed.edu
The general transcription factor TFIID is composed of the TATA box
binding protein (TBP) and multiple TBP-associated factors (TAFs) [1–3].
In yeast, promoters can be grouped into two classes based on the involvement
of TAFs [4, 5]. TAF-dependent (TAFdep) promoters require TAFs
for transcription, and TBP and TAFs are present at comparable levels on
these promoters. TAF-independent (TAFind) promoters do not
require TAFs for activity, and TAFs are either absent or present
at levels far below those of TBP on these
promoters. Here, we demonstrate that the upstream activating sequence
(UAS) mediates the selective
recruitment of TAFs to TAFdep promoters. A TAFind
UAS fails to recruit TAFs and to direct efficient
transcription when inserted upstream of a TAFdep core
promoter. This transcriptional defect can be overcome
by a potent activator, indicating that a strong activation domain
can compensate for the absence of TAFs on a
TAFdep core promoter. Our results reveal a requirement
for compatibility between the UAS and core promoter
and thus help explain previous reports that only certain yeast UAS-core
promoter combinations and mammalian
enhancer-promoter combinations are efficiently transcribed [6–11].
The differential recruitment of TAFs by
UASs provides strong evidence for the proposal that in vivo
TAFs are the targets of some, but not all,
activators.
1. Frenster JH, "Nuclear RNA Species Activate DNA Transcription Within Chromatin", FASEB Journal, Vol. 13, No. 7, A1506 (April 23, 1999).
2. Herstein PR, and Frenster JH, "Mated Models of Gene Regulation in Eukaryotes".
3. Frenster JH, "Ultrastructural Probes of Active
DNA Sites, and the RNA Activators of DNA".