title: Cloning and in vivo functional analysis by disruption of a gene encoding the gamma-butyrolactone autoregulator receptor from Streptomyces natalensis.
abstract: A gene encoding a gamma-butyrolactone autoregulator receptor, which has a common activity as DNA-binding transcriptional repressors controlling secondary metabolism and/or morphological differentiation in Streptomyces, was cloned from a natamycin producer, Streptomyces natalensis. PCR using the primers designed for the two highly conserved regions of Streptomyces autoregulator receptors (BarA, FarA, ScbR, and ArpA) gave a 102-bp band. The sequence of this band had a high similarity to the expected region of a receptor gene. By genomic Southern hybridization with the 102-bp insert as a probe, a 687-bp intact receptor gene (sngR) was obtained from S. natalensis. To clarify the in vivo function of sngR, a sngR-disrupted strain was constructed, and the phenotypes were compared with those of the wild-type strain. The sngR-disruptants started natamycin production 6 h earlier and showed a 4.6-fold higher production of natamycin than the wild-type strain. In addition, the sporulation began earlier and the number of spores was tenfold more abundant than that of the wild-type strain. All the phenotypes were restored back to the original phenotypes of the wild-type strain by complementation with the intact sngR, indicating that the autoregulator receptor protein of S. natalensis acts as a primary negative regulator both on the biosynthesis of natamycin and sporulation.
authors.affiliation: Department of Food Science and Biotechnology, Division of Life Science, Kyungnam University, 449 Wolyong-Dong, Masan 631-701, Republic of Korea.
authors.forename: Kang-Mu
authors.initials: KM
authors.lastname: Lee
authors.forename: Chang-Kwon
authors.initials: CK
authors.lastname: Lee
authors.forename: Sun-Uk
authors.initials: SU
authors.lastname: Choi
authors.forename: Hae-Ryong
authors.initials: HR
authors.lastname: Park
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kitani
authors.forename: Takuya
authors.initials: T
authors.lastname: Nihira
authors.forename: Yong-Il
authors.initials: YI
authors.lastname: Hwang
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D010866:Natamycin / Q000096:biosynthesis; D010802:Phylogeny; D011963:Receptors, GABA-A / Q000235:genetics*; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism*
chemical_list: C037481:4-butyrolactone receptor; D011963:Receptors, GABA-A; D010866:Natamycin