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Functional conservation of PAS–LuxR transcriptional regulators in polyene macrolide biosynthesis

Paper ID Volume ID Publish Year Pages File Format Full-Text
31777 44837 2011 12 PDF Available
Title
Functional conservation of PAS–LuxR transcriptional regulators in polyene macrolide biosynthesis
Abstract

Control of polyene macrolide production in Streptomyces natalensis is mediated by the PAS–LuxR transcriptional activator PimM. Expression of target genes in this strain is positively regulated by binding of the regulator to 14-nucleotide sites showing dyad symmetry, and overlapping the -35 element of each promoter. These sequences have been found in the upstream regions of genes belonging to different polyene biosynthetic gene clusters. All the sequences in the amphotericin, nystatin, and filipin clusters were cloned and the binding of PimM to all of them has been shown by electrophoretic mobility shift assays. The precise binding regions were investigated by DNaseI protection studies. Results indicated that PAS–luxR regulators share the same regulatory pattern in different polyene-producing strains, these genes being responsible for polyketide chain construction, and when available, the genes for sugar dehydration and attachment, and the ABC transporters, the targets for regulation. Information content analysis of the 24 sequences protected in target promoters was used to refine the information-based model of the binding site. This site now spans 16 nucleotides and adjusts to the consensus CTVGGGAWWTCCCBAG. Gene complementation of S. natalensis ΔpimM with a single copy of heterologous regulators of the PAS/LuxR class integrated into the chromosome, such as amphRIV, nysRIV, or pteF, restored antifungal production, thus proving the functional conservation of these regulators. Introduction of a single copy of pimM into the amphotericin producing strain Streptomyces nodosus, or into the filipin producing strain S. avermitilis, boosted the production of both polyenes, thus indicating that the expression of the PAS–LuxR regulator constitutes a bottleneck in the biosynthesis of the antifungal, and also that these regulators are fully exchangeable. This work is the first report of a general mechanism regulating polyene production.

► Control of polyene production is mediated by PAS–LuxR transcriptional activators. ► These regulators share the same regulatory pattern in different strains. ► PAS–LuxR regulators bind the consensus sequence CTVGGGAWWTCCCBAG. ► Expression of these regulators constitutes a bottleneck in polyene biosynthesis.

Keywords
Antibiotic biosynthesis; Antifungal agent; PAS domain; Polyene macrolide; Regulator binding site; Streptomyces
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Functional conservation of PAS–LuxR transcriptional regulators in polyene macrolide biosynthesis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 13, Issue 6, November 2011, Pages 756–767
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us