title: The RNA-Binding Chaperone Hfq Is an Important Global Regulator of Gene Expression in Pasteurella multocida and Plays a Crucial Role in Production of a Number of Virulence Factors, Including Hyaluronic Acid Capsule.
abstract: The Gram-negative bacterium Pasteurella multocida is the causative agent of a number of economically important animal diseases, including avian fowl cholera. Numerous P. multocida virulence factors have been identified, including capsule, lipopolysaccharide (LPS), and filamentous hemagglutinin, but little is known about how the expression of these virulence factors is regulated. Hfq is an RNA-binding protein that facilitates riboregulation via interaction with small noncoding RNA (sRNA) molecules and their mRNA targets. Here, we show that a P. multocida hfq mutant produces significantly less hyaluronic acid capsule during all growth phases and displays reduced in vivo fitness. Transcriptional and proteomic analyses of the hfq mutant during mid-exponential-phase growth revealed altered transcript levels for 128 genes and altered protein levels for 78 proteins. Further proteomic analyses of the hfq mutant during the early exponential growth phase identified 106 proteins that were produced at altered levels. Both the transcript and protein levels for genes/proteins involved in capsule biosynthesis were reduced in the hfq mutant, as were the levels of the filamentous hemagglutinin protein PfhB2 and its secretion partner LspB2. In contrast, there were increased expression levels of three LPS biosynthesis genes, encoding proteins involved in phosphocholine and phosphoethanolamine addition to LPS, suggesting that these genes are negatively regulated by Hfq-dependent mechanisms. Taken together, these data provide the first evidence that Hfq plays a crucial role in regulating the global expression of P. multocida genes, including the regulation of key P. multocida virulence factors, capsule, LPS, and filamentous hemagglutinin.
authors.affiliation: Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
authors.forename: Marianne
authors.initials: M
authors.lastname: Mégroz
authors.affiliation: Department of Biochemistry and Molecular Biology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
authors.forename: Oded
authors.initials: O
authors.lastname: Kleifeld
authors.affiliation: Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
authors.forename: Amy
authors.initials: A
authors.lastname: Wright
authors.affiliation: Monash Bioinformatics Platform, Monash University, Clayton, Victoria, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Powell
authors.affiliation: Monash Bioinformatics Platform, Monash University, Clayton, Victoria, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Harrison
authors.affiliation: Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Adler
authors.affiliation: Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
authors.forename: Marina
authors.initials: M
authors.lastname: Harper
authors.affiliation: Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia john.boyce@monash.edu.
authors.forename: John D
authors.initials: JD
authors.lastname: Boyce
mesh_terms: D016667:Bacterial Capsules / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D035001:Host Factor 1 Protein / Q000235:genetics / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism*; D016979:Pasteurella multocida / Q000235:genetics* / Q000378:metabolism*; D020543:Proteome / Q000032:analysis; D037521:Virulence Factors / Q000378:metabolism*
chemical_list: D035001:Host Factor 1 Protein; D020543:Proteome; D037521:Virulence Factors; D006820:Hyaluronic Acid