title: Suppressor analysis of eepR mutant defects reveals coordinate regulation of secondary metabolites and serralysin biosynthesis by EepR and HexS.
abstract: The EepR transcription factor positively regulates secondary metabolites and tissue-damaging metalloproteases. To gain insight into mechanisms by which EepR regulates pigment and co-regulated factors, genetic suppressor analysis was performed. Suppressor mutations that restored pigment to the non-pigmented ∆eepR mutant mapped to the hexS ORF. Mutation of hexS also restored haemolysis, swarming motility and protease production to the eepR mutant. HexS is a known direct and negative regulator of secondary metabolites in Serratia marcescens and is a LysR family regulator and an orthologue of LrhA. Here, we demonstrate that HexS directly controls eepR and the serralysin gene prtS. EepR was shown to directly regulate eepR expression but indirectly regulate hexS expression. Together, these data indicate that EepR and HexS oppose each other in controlling stationary phase-associated molecules and enzymes.
authors.affiliation: Charles T. Campbell Ophthalmic Microbiology Laboratory, Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, PA, USA.
authors.forename: Robert M Q
authors.initials: RMQ
authors.lastname: Shanks
authors.affiliation: Charles T. Campbell Ophthalmic Microbiology Laboratory, Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, PA, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Stella
authors.affiliation: Present address: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA.|Charles T. Campbell Ophthalmic Microbiology Laboratory, Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, PA, USA.
authors.forename: Roni M
authors.initials: RM
authors.lastname: Lahr
authors.affiliation: Present address: Children's Hospital of Philadelphia, Philadelphia, PA, USA.|Charles T. Campbell Ophthalmic Microbiology Laboratory, Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, PA, USA.
authors.forename: Marissa A
authors.initials: MA
authors.lastname: Aston
authors.affiliation: Charles T. Campbell Ophthalmic Microbiology Laboratory, Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, PA, USA.
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Brothers
authors.affiliation: Charles T. Campbell Ophthalmic Microbiology Laboratory, Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, PA, USA.
authors.forename: Jake D
authors.initials: JD
authors.lastname: Callaghan
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Cihad
authors.initials: C
authors.lastname: Sigindere
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004251:DNA Transposable Elements / Q000235:genetics; D047630:Depsipeptides / Q000096:biosynthesis; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005407:Flagella / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D005809:Genes, Regulator / Q000235:genetics*; D013058:Mass Spectrometry; D008666:Metalloendopeptidases / Q000096:biosynthesis*; D011353:Prodigiosin / Q000096:biosynthesis; D064210:Secondary Metabolism / Q000235:genetics*; D012706:Serratia marcescens / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D047630:Depsipeptides; D014157:Transcription Factors; C009246:serratamolide; C073470:LysR protein, Bacteria; D008666:Metalloendopeptidases; C095666:serralysin; D011353:Prodigiosin