A trans-acting leader RNA from a Salmonella virulence gene

The intracellular pathogen Salmonella enterica serovar Typhimurium must move toward nutrients to obtain food. However, at the same time, it has to evade the host immune system. Because bacterial flagella are required for both bacterial movement and immune detection, production of flagella must be tightly regulated during infection. Here, we establish that Salmonella produces a leader RNA from the mgtCBR virulence operon and degrades mRNAs of the fljB phase 2 flagellin gene during infection. Our finding indicates a direct link between a virulence determinant and motility via a trans-acting leader RNA derived from the virulence determinant gene in a given host environment.