title: Toxicity of ricinoleic acid production in fission yeast Schizosaccharomyces pombe is suppressed by the overexpression of plg7, a phospholipase A2 of a platelet-activating factor (PAF) family homolog.
abstract: In an effort to produce ricinoleic acid (RA), an important natural raw material with great values as a petrochemical replacement, in Schizosaccharomyces pombe, we introduced Claviceps purpurea oleate Δ12-hydroxylase gene (CpFAH12) to S. pombe, putting it under the control of an inducible nmt1 promoter. However, RA was toxic to S. pombe and the cells expressing CpFAH12 grew poorly at the normal growth temperature 30 °C. To address its toxic mechanism in S. pombe, we screened for a S. pombe cDNA library and identified plg7, which encodes a phospholipase A2, as a suppressor that restored the growth defect without affecting the RA production. A lacZ fusion experiment showed that the expression of plg7 was inducible by RA. Thin layer chromatographic analysis confirmed a reduction in RA moiety in phospholipids and a concomitant increase in free RA in the plg7 overexpressed strain. Since RA is synthesized at the sn-2 position of phosphatidylcholine by Fah12p, and phospholipase A2 hydrolyzes the sn-2 acyl bond of phospholipids, we speculate that plg7 is a stress-responsive gene, and removal of RA moieties from phospholipids, major components of lipid bilayer membrane, by Plg7p would be its suppression mechanism.
authors.affiliation: AIST Tsukuba Central 6, National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8566, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yazawa
authors.forename: Roman
authors.initials: R
authors.lastname: Holic
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kumagai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uemura
mesh_terms: D015536:Down-Regulation; D060847:Metabolic Engineering; D054467:Phospholipases A2 / Q000235:genetics* / Q000378:metabolism; D012277:Ricinoleic Acids / Q000378:metabolism* / Q000633:toxicity*; D012568:Schizosaccharomyces / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D012277:Ricinoleic Acids; D029702:Schizosaccharomyces pombe Proteins; D054467:Phospholipases A2; C030521:ricinoleic acid