Purification, Identification, and Properties of a Saccharomyces cerevisiae Oleate-activated Upstream Activating Sequence-binding Protein That Is Involved in the Activation of POX1(*)
- From the Department of Cell Biology/Anatomy and the
- Department of Biochemistry, Mount Sinai School of Medicine, New York, New York 10029
- ↵§American Heart Association Established Investigator. To whom correspondence should be addressed: Dept. of Cell Biology/Anatomy, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029. Tel.: 212-241-0981; Fax: 212-860-1174.
Abstract
Peroxisomes have a central function in lipid metabolism, and it is well established that these organelles are inducible by many compounds including fatty acids. Peroxisomes are the sole site for the β-oxidation of fatty acids in yeast. The first and rate-limiting enzyme of this cycle is fatty acyl-CoA oxidase. The gene encoding this enzyme in Saccharomyces cerevisiae (POX1) undergoes a complex regulation that is dependent on the growth environment. When this yeast is grown in medium containing oleic acid as the main carbon source, peroxisomes are induced and POX1 expression is activated. When cells are grown in the presence of glucose, the expression of POX1 mRNA is repressed, whereas growth on a carbon source such as glycerol or raffinose causes derepression. This rigorous regulation is brought about by the complex interactions between trans-acting factors and cis-elements in the POX1 promoter. Previously, we characterized regulatory elements in the promoter region of POX1 that are involved in the repression and activation of this gene (Wang, T., Luo, Y., and Small, G. M.(1994) J. Biol. Chem. 269, 24480-24485). In this study we have purified and identified an oleate-activated transcription factor (Oaf1p) that binds to the activating sequence (UAS1) in the POX1 gene. The protein has a predicted molecular mass of approximately 118 kDa.
Footnotes
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↵* This work was funded by American Heart Association Grant AHA 92-850. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
- Received December 8, 1995.
- Revision received February 21, 1996.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
