title: A novel role of 'pseudo'γ-butyrolactone receptors in controlling γ-butyrolactone biosynthesis in Streptomyces.
abstract: In streptomycetes, a quorum-sensing mechanism mediated by γ-butyrolactones (GBLs) and their cognate receptors was known to trigger secondary metabolism and morphological differentiation. However, many aspects on the control of GBL signal production are not understood. In this work, we report that ScbR2, the pseudo GBL receptor in Streptomyces coelicolor, negatively controls the biosynthesis of γ-butyrolactone (SCB1) by directly repressing the transcription of scbA, which encodes the key enzyme for SCB1 biosynthesis. Similarly, the pseudo GBL receptor JadR2 in Streptomyces venezuelae was shown to repress the expression of jadW1, which also encodes the putative GBL synthase. These regulatory relationships were verified in Escherichia coli using lux-based reporter constructs. Additionally, the temporal expression profiles of scbA, scbR2 and scbR (receptor gene for SCB1) were examined in Streptomyces coelicolor, which showed the sequential expression of ScbR/R2 regulators in the control of SCB1 production. Overall, our results clearly demonstrated that pseudo GBL receptors play a novel role in controlling GBL biosynthesis in streptomycetes. As ScbR/R2 homologues and their binding sites upstream of GBL synthase genes are commonly found in Streptomyces species, and ScbR2 homologues cross-recognize each other's target promoters, the ScbA/R/R2 quorum-sensing regulatory system appears to represent an evolutionarily conserved signal control mechanism.
authors: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors: Juan
authors: J
authors: Wang
authors: Weishan
authors: W
authors: Wang
authors: Linqi
authors: L
authors: Wang
authors: Guifeng
authors: G
authors: Zhang
authors: Keqiang
authors: K
authors: Fan
authors: Huarong
authors: H
authors: Tan
authors: Keqian
authors: K
authors: Yang
mesh_terms: D015107:4-Butyrolactone / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D053898:Biosynthetic Pathways; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism*; D048372:Streptomyces coelicolor / Q000235:genetics / Q000378:metabolism*
chemical_list: C037481:4-butyrolactone receptor; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; C446303:ScbA protein, Streptomyces; D015107:4-Butyrolactone