Identification of genes affecting lipid content using transposon mutagenesis in Saccharomyces cerevisiae

• Published in: Bioscience, biotechnology, and biochemistry Vol. 70; no. 3; pp. 646 - 653
• Main Authors: Kamisaka, Y.(National Inst. of Advanced Industrial Science and Technology Tsukuba, Ibaraki (Japan)), Noda, N, Tomita, N, Kimura, K, Kodaki, T, Hosaka, K
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Society for Bioscience, Biotechnology, and Agrochemistry 2006; Japan Society for Bioscience Biotechnology and Agrochemistry; Oxford University Press
• Subjects: Adenosine Triphosphatases; Biological and medical sciences; Cell Shape; CONTENIDO DE LIPIDOS; DNA Transposable Elements - genetics; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Fatty Acids - pharmacology; Fundamental and applied biological sciences. Psychology; GENE; Gene Deletion; GENES; IRA2; lipid accumulation; LIPID CONTENT; Lipid Metabolism; MUTACION; Mutagenesis - genetics; MUTATION; Open Reading Frames; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - cytology; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; SNF2; TENEUR EN LIPIDES; Transcription Factors - genetics; Transcription Factors - metabolism; transposon mutagenesis; SNF2; Yeast; Transposon; Lipids; Identification; Transposable element; Scicclniromyces cerevisiae; Accumulation; transposon mutagenesis; Fungi; Gene; Mutagenesis; IRA2; Ascomycetes; Saccharomyces cerevisiae; lipid accumulation; Thallophyta
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.70.646

Genes involved in lipid accumulation were identified in Saccharomyces cerevisiae using transposon insertion mutagenesis. Five ORFs, such as SNF2, IRA2, PRE9, PH090, and SPT21 were found from the analysis of the insertion sites in transposon insertion mutants with higher lipid content. Since these ORFS are not directly involved in storage lipid biosynthesis, we speculate that they are involved in carbon fluxes into storage lipids in response to nutrient conditions. Lipid analysis of disruptants of these ORFS indicated that the deltasnf2, and deltaira2 disruptants had significantly higher lipid content. Cultivation in a nitrogen-limited medium increased the lipid content in all disruptants, among which the Apre9 disruptant was the most sensitive to nitrogen limitation. We then focused on the deltasnf2 disruptant due to its higher lipid content and its function as a regulator of phospholipid synthesis. Lipid class analysis indicated that triacylglycerol and free fatty acids contributed to the increase in total lipids of the deltasnf2 disruptant. The addition of exogenous fatty acids was not so effective at increasing the lipid content in the deltasnf2 disruptant as it was in the wild type. It should be noticed that exogenous free linoleic acid was much higher in the deltasnf2 disruptant than in the wild type, as in the case of endogenous free fatty acids. In addition, the incorporation of exogenous fatty acids into cells increased in the disruptant suggesting that fatty acid transporters were regulated by SNF2. The results suggest that metabolic fluxes into storage lipids, which are activated in the deltasnf2 disruptant, is repressed by the incorporation of exogenous fatty acids. They provide new insight into the biosynthesis of storage lipids in yeast.