Specificity of unsaturated fatty acid-regulated expression of the Saccharomyces cerevisiae OLE1 gene

• Published in: The Journal of biological chemistry Vol. 267; no. 9; pp. 5931 - 5936
• Main Authors: McDonough, V.M. (Rutgers University, Piscataway, NJ), Stukey, J.E, Martin, C.E
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 25.03.1992
• Subjects: ACIDE GRAS INSATURE; ACIDOS GRASOS INSATURADOS; beta-Galactosidase - biosynthesis; beta-Galactosidase - genetics; Biological and medical sciences; EXPRESION GENICA; EXPRESSION DES GENES; Fatty Acid Desaturases - biosynthesis; Fatty Acid Desaturases - genetics; Fatty Acids, Unsaturated - pharmacology; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Enzymologic - drug effects; Gene Expression Regulation, Fungal - drug effects; Genes, Fungal; GENETICA; GENETIQUE; Molecular and cellular biology; Molecular genetics; OXIDORREDUCTASAS; OXYDOREDUCTASE; Promoter Regions, Genetic; Recombinant Fusion Proteins - biosynthesis; Restriction Mapping; RNA, Fungal - genetics; RNA, Fungal - isolation & purification; RNA, Messenger - genetics; RNA, Messenger - metabolism; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Stearoyl-CoA Desaturase; TATA Box; Fungi; Regulation(control); Yeast; Enzymatic activity; Enzyme; Transcription repressor; Ascomycetes; Gene expression; Fatty acids; Saccharomyces cerevisiae; Thallophyta; Acyl-CoA desaturase
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)42644-0

The Saccharomyces cerevisiae OLE1 gene encodes the delta-9 fatty acid desaturase, an enzyme which forms the monounsaturated palmitoleic (16:1) and oleic (18:1) fatty acids from palmitoyl (16:0) or stearoyl (18:0) CoA. Previous studies demonstrated that OLE1 mRNA levels and desaturase enzyme activity are repressed when either 16:1 delta-9 and 18:1 delta-9 are added to the growth medium (1). The polyunsaturate, linoleic acid (18:2, delta-9,12), which is not a product of the enzyme, is also a strong repressor. The specificity of the OLE1 transcriptional regulatory sensor was examined by testing the response of OLE1 promoter-lacZ fusion reporter genes to fatty acids that differ in chain length, degree of unsaturation and double bond positions. Monounsaturated and polyunsaturated fatty acids that contain a delta-9 double bond are strong repressors of reporter gene activity and native OLE1 mRNA levels. Monounsaturated fatty acids containing double bonds in the delta-10, delta-11, or delta-5 positions showed no repression of reporter enzyme levels although they were rapidly incorporated into membrane lipids and some supported growth of an OLE1 gene disrupted strain. Although 17:1 delta-10 does not repress OLE1 transcription, lipid analysis showed that it replaces almost all of the endogenous 16:1 delta-9 and 18:1 delta-9 in cellular lipids and OLE1 mRNA levels are strongly repressed. This suggests that additional systems regulate desaturase activity by post-transcriptional mechanisms that differ from the transcriptional sensor in their responses to specific fatty acids