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The SV40 core sequence functions as a repressor element in yeast.
Z Y Zhang-Keck1, W A Kibbe, W S Moye-Rowley
1Division of Chemistry, California Institute of Technology, Pasadena 91125.
The Journal of Biological Chemistry
|November 15, 1991
Summary
A newly identified upstream repressor element (URE) in yeast inhibits transcriptional activity. This repression can be overcome by multiple activator sites, suggesting complex regulatory interactions.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Transcriptional Regulation
Background:
- Previous studies demonstrated that the AP-1 recognition element (ARE) from SV40 activates yeast transcription.
- The AP-2/AP-3 recognition element (core sequence TGTGGAAAG) did not activate transcription in prior experiments.
Purpose of the Study:
- To investigate the function of the SV40 enhancer core sequence in yeast transcription.
- To characterize a novel repressor element identified in yeast.
Main Methods:
- Cloning the core sequence adjacent to a yeast upstream activation sequence (UAS).
- Assessing transcriptional activity with varying URE and UAS/TATA box placements and orientations.
- Utilizing gel-shift analysis and protein blots to identify URE-binding proteins.
Main Results:
- The core sequence, termed upstream repressor element (URE), inhibits UAS-mediated transcription.
- Repression is orientation-independent and effective even when URE is separated from UAS by up to 214 bp.
- Multiple activator sites can overcome URE-mediated repression.
- Two polypeptide chains capable of binding the URE were detected in yeast.
Conclusions:
- The URE acts as a repressor of transcription in yeast.
- Repression mechanisms may involve direct interactions between URE-binding proteins and GCRE or between activators and repressors of general transcription factors.