title: Enrichment of yeast thioredoxin by green tea extract through activation of Yap1 transcription factor in Saccharomyces cerevisiae.
abstract: Thioredoxin (TRX) is an important antioxidant present in all types of organisms. Besides its role as an antioxidant, TRX protects the gastric mucosa due to its antiinflammatory effect. In addition, TRX decreases allergenicity; therefore, the oral administration of TRX is of considerable interest with respect to its clinical use as well as the development of functional foods containing TRX. We have attempted to enrich the cellular TRX content in Saccharomyces cerevisiae, and found that green tea extract (Sunphenon), which is rich in catechins (polyphenols), activates the Yap1 transcription factor, leading to the induction of TRX2, a target of Yap1. Production of yeast TRX was monitored by both a TRX2-lacZ reporter expression assay and Western blotting using an anti-yeast TRX antibody. Maximal production of TRX was achieved in a medium containing 0.1% green tea extract at pH 7.6. We discuss the underlying mechanism by which green tea extract activates Yap1.
authors.affiliation: Laboratory of Molecular Microbiology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Takatsume
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Maeta
authors.forename: Shingo
authors.initials: S
authors.lastname: Izawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D008565:Membrane Proteins / Q000096:biosynthesis; D010636:Phenols / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D013879:Thioredoxins / Q000032:analysis* / Q000096:biosynthesis; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D008565:Membrane Proteins; D010636:Phenols; D029701:Saccharomyces cerevisiae Proteins; C516110:TRX2 protein, S cerevisiae; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae; C074269:Sunphenon; D013879:Thioredoxins