Role of ProQ in Salmonella virulence - pulse expression

FinO-domain proteins such as ProQ of the model pathogen Salmonella enterica have emerged as a new class of major RNA-binding proteins in bacteria. ProQ has been shown to target hundreds of transcripts including mRNAs from many virulence regions but its role, if any, in bacterial pathogenesis has not been studied. Here, using a Dual RNA-seq approach to profile ProQ-dependent gene expression changes as Salmonella infects human cells, we reveal dysregulation of bacterial motility, chemotaxis and virulence genes which is accompanied by altered mitogen-activated protein kinase signaling in the host. Comparison with Hfq, Salmonella’s other major RNA chaperone, reinforces the notion that these two global RNA binding proteins work in parallel to ensure full virulence. Of newly discovered infection-associated ProQ-bound small noncoding RNAs, we show that STnc540 represses a virulence-related magnesium transporter mRNA in a ProQ-dependent manner. Together, this comprehensive study uncovers the relevance of ProQ for Salmonella infection and highlights the importance of RNA-binding proteins in regulating bacterial virulence programs. Bacterial RNA-seq