The Role and Targets of the RNA-Binding Protein ProQ in the Gram-Negative Bacterial Pathogen Pasteurella multocida

Abstract

Regulation in P. multocida involving the RNA-binding protein Hfq is required for hyaluronic acid capsule production and virulence. This study further expands our understanding of riboregulation by examining the role of a second RNA-binding protein, ProQ, in transcript regulation and abundance in P. multocida .

FinO/ProQ-family proteins: an evolutionary perspective

“…Such structural elements are naturally rife in intrinsic terminators of bacterial transcripts. Indeed, most known RNA partners of FinO/ProQ-family proteins engage the protein via their terminator structures ( Figures 1 and 2 ), which was confirmed by both focused studies in vitro and by global interactomic profiling of ligands in vivo [ 4 , 33 , 36 , 37 , 39 , 40 , 46 , 48 , 49 , 58 ]. However, a few prominent processed ProQ ligands, such as certain phage-encoded and intragenic sRNAs, are devoid of terminators and appear to interact via other similarly structured elements [ 3 , 36 , 62 ].…”

“…In other Enterobacteriaceae ( Dickeya dadantii, Erwinia amylovora and Photorhabdus luminescens ), ProQ also seems to act as a general RBP and to be involved in many of the same physiological functions, such as osmolarity control, motility, biofilm formation, and virulence [ 45–47 ]. In the more distantly related Pasteurella multocida , ProQ was found to interact with ∼70 RNA species (mRNAs, sRNAs, tRNAs) and affect, mostly positively, the expression of ∼180 genes linked to carbohydrate metabolism and translation [ 48 ]. In the β-proteobacterium Neisseria meningitidis , a minimalistic ProQ homologue with RNA chaperone activity similarly interacts with ∼180 mRNAs and sRNAs and affects the transcript levels of >250 genes involved in multiple pathways, including energy production and amino acid metabolism [ 23 , 49 ].…”

“…Outside a base-pairing context, enterobacterial ProQ sitting on the terminator of the cspE mRNA shields it from the 3′-exoribonuclease RNase II [ 36 ] and N. meningitidis ProQ can protect the rmpG mRNA from PNPase-mediated degradation in vitro [ 49 ]. A general protective role of ProQ has been observed genome-wide in S. enterica [ 36 ], P. multocida [ 48 ] and N. meningitidis [ 49 ].…”

“…However, the exact targets and regulons of these proteins may be quite different from one species to another. For example, E. coli and D. dadantii ProQ proteins are involved in resistance to osmotic stress [ 45 , 74 ], but this role is not conserved in P. multocida [ 48 ]. Whereas in E. coli and P. luminescens ProQ positively regulates biofilm formation [ 38 , 47 ], its effect is opposite in the closely related E. amylovora and D. dadantii [ 45 , 46 ], and null in the phylogenetically distant N. meningitidis [ 49 ].…”

“…The sources of this functional divergence are likely both extrinsic (i.e. linked to differences in transcriptomes between species and even between growth conditions for the same species [ 3 , 36 , 37 , 39 , 46 , 48 , 49 , 72 ]) and intrinsic (i.e. stemming from the proteins themselves).…”