title: Isolation and characterization of a reducing polyketide synthase gene from the lichen-forming fungus Usnea longissima.
abstract: The reducing polyketide synthases found in filamentous fungi are involved in the biosynthesis of many drugs and toxins. Lichens produce bioactive polyketides, but the roles of reducing polyketide synthases in lichens remain to be clearly elucidated. In this study, a reducing polyketide synthase gene (U1PKS3) was isolated and characterized from a cultured mycobiont of Usnea longissima. Complete sequence information regarding U1PKS3 (6,519 bp) was obtained by screening a fosmid genomic library. A U1PKS3 sequence analysis suggested that it contains features of a reducing fungal type I polyketide synthase with β-ketoacyl synthase (KS), acyltransferase (AT), dehydratase (DH), enoyl reductase (ER), ketoacyl reducatse (KR), and acyl carrier protein (ACP) domains. This domain structure was similar to the structure of ccRadsl, which is known to be involved in resorcylic acid lactone biosynthesis in Chaetomium chiversii. The results of phylogenetic analysis located U1PKS3 in the clade of reducing polyketide synthases. RT-PCR analysis results demonstrated that UIPKS3 had six intervening introns and that UIPKS3 expression was upregulated by glucose, sorbitol, inositol, and mannitol.
authors: Korean Lichen Research Institute, Sunchon National University, Sunchon, 540-742, Republic of Korea.
authors: Yi
authors: Y
authors: Wang
authors: Jung A
authors: JA
authors: Kim
authors: Yong Hwa
authors: YH
authors: Cheong
authors: Yogesh
authors: Y
authors: Joshi
authors: Young Jin
authors: YJ
authors: Koh
authors: Jae-Seoun
authors: JS
authors: Hur
mesh_terms: D000595:Amino Acid Sequence; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D008011:Lichens / Q000382:microbiology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D048630:Polyketide Synthases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020949:Usnea / Q000145:classification / Q000201:enzymology*
chemical_list: D005656:Fungal Proteins; D012333:RNA, Messenger; D048630:Polyketide Synthases