title: Saccharomyces cerevisiae strain expressing a plant fatty acid desaturase produces polyunsaturated fatty acids and is susceptible to oxidative stress induced by lipid peroxidation.
abstract: Although oxygen is essential for aerobic organisms, it also forms potentially harmful reactive oxygen species. For its simplicity, easy manipulation, and cultivation conditions, yeast is used as an attractive model in oxidative stress research. However, lack of polyunsaturated fatty acids in yeast membranes makes yeast unsuitable for research in the field of lipid peroxidation. Therefore, we have constructed a yeast strain expressing a Delta12 desaturase gene from the tropical rubber tree, Hevea brasiliensis. This yeast strain expresses the heterologous desaturase in an active form and, consequently, produces Delta9/Delta12 polyunsaturated fatty acids under inducing conditions. The functional expression of the heterologous desaturase did not affect cellular morphology or growth, indicating no general adverse effect on cellular physiology. However, the presence of polyunsaturated fatty acids changed the yeast's sensitivity to oxidative stress induced by addition of paraquat, tert-butylhydroperoxide, and hydrogen peroxide. This difference in sensitivity to the latter was followed by the formation of 4-hydroxy-2-nonenal, one of the end products of linoleic fatty acid peroxidation, which is known to play a role in cell growth control and signaling. Here we show that this yeast strain conditionally expressing the Delta12 desaturase gene provides a novel and well-defined eukaryotic model in lipid peroxidation research. Its potential to investigate the molecular basis of responses to oxidative stress, in particular the involvement of reactive aldehydes derived from fatty acid peroxidation, especially 4-hydroxy-2-nonenal, will be addressed.
authors.affiliation: Institute Rudjer Boskovic, Zagreb, Croatia.
authors.forename: Ana
authors.initials: A
authors.lastname: Cipak
authors.forename: Meinhard
authors.initials: M
authors.lastname: Hasslacher
authors.forename: Oksana
authors.initials: O
authors.lastname: Tehlivets
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Collinson
authors.forename: Morana
authors.initials: M
authors.lastname: Zivkovic
authors.forename: Tanja
authors.initials: T
authors.lastname: Matijevic
authors.forename: Willibald
authors.initials: W
authors.lastname: Wonisch
authors.forename: Georg
authors.initials: G
authors.lastname: Waeg
authors.forename: Ian W
authors.initials: IW
authors.lastname: Dawes
authors.forename: Neven
authors.initials: N
authors.lastname: Zarkovic
authors.forename: Sepp D
authors.initials: SD
authors.lastname: Kohlwein
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005609:Free Radicals / Q000633:toxicity; D028482:Hevea / Q000201:enzymology / Q000235:genetics; D006861:Hydrogen Peroxide / Q000633:toxicity; D015227:Lipid Peroxidation; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010269:Paraquat / Q000633:toxicity; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D020122:tert-Butylhydroperoxide / Q000633:toxicity
chemical_list: D000447:Aldehydes; D005231:Fatty Acids, Unsaturated; D005609:Free Radicals; D010940:Plant Proteins; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide; D044943:Fatty Acid Desaturases; C040448:delta-12 fatty acid desaturase; C027576:4-hydroxy-2-nonenal; D010269:Paraquat