title: Metabolic and regulatory engineering of Serratia marcescens: mimicking phage-mediated horizontal acquisition of antibiotic biosynthesis and quorum-sensing capacities.
abstract: Serratia marcescens is an important cause of opportunistic human infections. Many, but not all, strains produce prodigiosin, a secondary metabolic, red-pigment antibiotic, the biosynthesis of which is directed by the pig gene cluster. Quorum sensing (QS) involves the production and detection of chemical signal molecules as a means to regulate gene expression in response to population cell density. Several strains of S. marcescens have previously been shown to possess an N-acyl-L-homoserine lactone (aHSL) QS system. This study aimed to determine the impact of introducing, by phage-mediated horizontal gene transfer, a biosynthetic gene cluster (pig) and a regulatory locus (aHSL QS) into strains lacking the respective trait. The pig cluster from S. marcescens ATCC 274 (Sma 274) was transferred to the non-pigmented strain, S. marcescens strain 12 (Sma 12). In the engineered strain, pigment was expressed and brought under the control of the recipient's native regulatory systems (aHSL QS and luxS). Moreover, transfer of the aHSL locus from Sma 12 to the non-QS Sma 274 resulted in the imposition of aHSL control onto a variety of native traits, including pigment production. In addition, during this study, the QS regulon of the clinical strain, Sma 12, was characterized, and some novel QS-regulated traits in S. marcescens were identified. The results have implications for the evolution and dissemination of biosynthetic and QS loci, illustrating the genetic modularity and ease of acquisition of these traits and the capacity of phages to act as vectors for horizontal gene transfer.
authors.affiliation: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Coulthurst
authors.affiliation: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
authors.forename: Neil R
authors.initials: NR
authors.lastname: Williamson
authors.affiliation: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
authors.forename: Abigail K P
authors.initials: AKP
authors.lastname: Harris
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
authors.forename: David R
authors.initials: DR
authors.lastname: Spring
authors.affiliation: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
authors.forename: George P C
authors.initials: GPC
authors.lastname: Salmond
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001483:Base Sequence; D005818:Genetic Engineering; D008969:Molecular Sequence Data; D005810:Multigene Family; D010641:Phenotype; D011353:Prodigiosin / Q000096:biosynthesis*; D012706:Serratia marcescens / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D011353:Prodigiosin