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Additive activation of yeast LEU4 transcription by multiple cis elements
1Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907-1153.
The Journal of Biological Chemistry
|March 10, 1995
Summary
Researchers identified five functional cis elements in the LEU4 promoter, revealing complex regulation of alpha-isopropylmalate synthase (LEU4) in yeast amino acid metabolism. These elements control gene expression through interactions with specific regulatory proteins.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Metabolic Regulation
Background:
- The LEU4 gene encodes alpha-isopropylmalate synthase, catalyzing the first committed step in leucine biosynthesis in Saccharomyces cerevisiae.
- The product, alpha-isopropylmalate, acts as both a metabolic intermediate and a co-activator for multiple genes.
- LEU4 expression is subject to complex regulation, suggesting significant metabolic importance.
Purpose of the Study:
- To analyze functional cis-acting elements within the LEU4 promoter.
- To elucidate the regulatory mechanisms governing LEU4 gene expression.
Main Methods:
- Promoter analysis to identify functional cis elements.
- Investigating the roles of identified elements in gene regulation.
Main Results:
- Five functional cis elements were identified in the LEU4 promoter.
- Three distal elements (UASLEU, GCE-A, GCE-B) mediate regulation by Leu3p and Gen4p, with additive and independent activation.
- Two proximal elements were localized, including a TATA consensus sequence element and a Bas2p binding site element involved in basal and phosphate-mediated regulation.
Conclusions:
- The LEU4 promoter contains multiple cis elements that orchestrate its complex regulation.
- These elements integrate signals from regulatory proteins (Leu3p, Gen4p, Bas2p) and cellular conditions (phosphate levels) to control leucine biosynthesis and related pathways.