Oral Presentation MedVetPATHOGENS 2018

Unravelling the Pasteurella multocida small RNA regulatory network (#50)

Emily Gulliver 1 , Marianne Mégroz 1 , Brandon Sy 2 , Julia Wong 2 , Deanna Deveson Lucas 1 , Ralf B Schittenhelm 3 , Oded Kleifeld 3 , David Powell 4 , Jai Tree 2 , Marina Harper 1 , John D Boyce 1
  1. Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia
  2. School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
  3. Monash Biomedical Proteomics Facility, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Vic, Australia
  4. Monash Bioinformatics Platform, Monash University, Monash, Victoria, Australia

Pasteurella multocida is a Gram-negative bacterium that is the causative agent of a number of economically important animal diseases, including avian fowl cholera. A number of P. multocida virulence factors have been identified, including capsule, lipopolysaccharide (LPS) and filamentous hemagglutinin, but little is known about how expression of these virulence factors is regulated. Small non-coding RNA molecules (sRNAs) are known to play important roles in regulation of bacterial protein production via sRNA/mRNA interactions that alter mRNA transcript stability and/or translational efficiency. As most sRNAs bind to their mRNA targets via a short sequence with limited complementarity, the RNA-binding protein chaperones Hfq or ProQ are usually required to facilitate the interaction. To assess the importance of sRNAs for regulation in P. multocida, we constructed independent P. multocida hfq and proQ mutants. The hfq mutant produced significantly less hyaluronic acid capsule during all growth phases and displayed reduced in vivo fitness compared with the wild-type strain, indicating sRNAs regulate crucial P. multocidavirulence factors. Global proteomic and transcriptomic analyses showed that the hfq mutant displayed altered expression of filamentous hemagglutinin as well as a number of capsule and LPS biosynthesis proteins. The proQ mutant showed no change in tested phenotypes but proteomic and transcriptomic analyses identified altered expression of tRNAs and sRNAs. To comprehensively identify P. multocida sRNAs we used a combination of RNA-Seq and Hfq- and ProQ-specific UV‐crosslinking co-immunoprecipitation, ligation and sequencing of hybrids (CLASH). These combined analyses identified more than 50 putative sRNAs. Twenty Hfq-associated and 34 ProQ-associated hybrids were identified using Hfq-CLASH. This is the first global identification of P. multocida sRNAs and confirmation that they play critical roles in P. multocida pathogenesis.