A bacterial translation activator with an intrinsically disordered RNA-binding region.

Abstract

Bacterial RNA-binding proteins (RBPs) that control the translation of multiple transcripts act largely as negative regulators. Here, we report the identification and characterization of a positive regulator of translation (called PhaF) in the opportunistic pathogen <i>Pseudomonas aeruginosa</i>. Using CLIP-seq and CLAP-seq we identify upward of 50 transcripts targeted by PhaF. We demonstrate that PhaF acts to stimulate the translation of target mRNAs by binding upstream of the Shine-Dalgarno sequence using one or more of the multiple KPAA motifs located in an intrinsically disordered region of the protein. Importantly, we show that PhaF plays a key physiological role in <i>P. aeruginosa</i> through its translational control of the <i>pslA</i> transcript required for exopolysaccharide synthesis and biofilm formation. Our findings uncover an activator of translation in bacteria that binds target transcripts using an RNA-binding region reminiscent of those that are prominent in eukaryotic RBPs.