title: LuxS coexpression enhances yields of recombinant proteins in Escherichia coli in part through posttranscriptional control of GroEL.
abstract: Cell-to-cell communication, or quorum sensing (QS), enables cell density-dependent regulation of bacterial gene expression which can be exploited for the autonomous-signal-guided expression of recombinant proteins (C. Y. Tsao, S. Hooshangi, H. C. Wu, J. J. Valdes, and W. E. Bentley, Metab. Eng. 12:291-297, 2010). Earlier observations that the metabolic potential of Escherichia coli is conveyed via the QS signaling molecule autoinducer-2 (AI-2) suggested that the capacity for protein synthesis could also be affected by AI-2 signaling (M. P. DeLisa, J. J. Valdes, and W. E. Bentley, J. Bacteriol. 183:2918-2928, 2001). In this work, we found that simply adding conditioned medium containing high levels of AI-2 at the same time as inducing the synthesis of recombinant proteins doubled the yield of active product. We have hypothesized that AI-2 signaling "conditions" cells as a natural consequence of cell-to-cell communication and that this could tweak the signal transduction cascade to alter the protein synthesis landscape. We inserted luxS (AI-2 synthase) into vectors which cosynthesized proteins of interest (organophosphorus hydrolase [OPH], chloramphenicol acetyltransferase [CAT], or UV-variant green fluorescent protein [GFPuv]) and evaluated the protein expression in luxS-deficient hosts. In this way, we altered the level of luxS in the cells in order to "tune" the synthesis of AI-2. We found conditions in which the protein yield was dramatically increased. Further studies demonstrated coincident upregulation of the chaperone GroEL, which may have facilitated higher yields and is shown for the first time to be positively regulated at the posttranscriptional level by AI-2. This report is the first to demonstrate that the protein synthesis capacity of E. coli can be altered by rewiring quorum sensing circuitry.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, 5115 Plant Sciences Building Number 036, College Park, MD 20742, USA.
authors.forename: Chen-Yu
authors.initials: CY
authors.lastname: Tsao
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Hyunmin
authors.initials: H
authors.lastname: Yi
authors.forename: John C
authors.initials: JC
authors.lastname: March
authors.forename: Matthew P
authors.initials: MP
authors.lastname: DeLisa
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Wood
authors.forename: James J
authors.initials: JJ
authors.lastname: Valdes
authors.forename: William E
authors.initials: WE
authors.lastname: Bentley
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006714:Homoserine / Q000031:analogs & derivatives / Q000494:pharmacology; D007783:Lactones / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; D006360:Heat-Shock Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D011994:Recombinant Proteins; D006714:Homoserine; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria