Merging of multiple signals regulating Δ9 fatty acid desaturase gene transcription in Saccharomyces cerevisiae

摘要: Fatty acid desaturation, which requires molecular oxygen (O2) as an electron acceptor, is catalyzed by Δ9 fatty desaturase, encoded OLE1 in Saccharomyces cerevisiae. Transcription of the gene repressed unsaturated acids (UFAs) and activated hypoxia low temperatures via endoplasmic reticulum membrane protein Mga2p. We previously reported isolation nfo3-1 (negative factor for OLE1) mutant, exhibits enhanced expression presence UFA under aerobic conditions. In this work, we demonstrated that NFO3 identical to mutation (renamed ole1-101) alters arginine-346, vicinity conserved histidine-rich motif essential catalytic function Ole1 protein, lysine. The ratio UFAs total ole1-101 mutant was 60%, compared 75% wild type, suggesting reduction relative levels intracellular activates transcription. However, cells grown oleic acid, level remained high, although amount almost same wild-type growing By contrast, when were with linoleic has a lower melting point than elevation due completely suppressed. These observations suggest activate transcription sensing not only level, but also fluidity or nature species itself. Furthermore, found acid-regulated (FAR) element O 2-regulated (O2R) promoter involved activation mutation, effects low-oxygen signal ole1-101-generated on additive. Taken together, these findings signals associated hypoxia, depletion common pathway.