Small RNA Sibling ryfA1 Influences Shigella dysenteriae Pathogenesis

Small regulatory RNAs (sRNAs) of Shigella dysenteriae and other pathogens are vital for the regulation of virulence-associated genes and processes. Here, we characterize RyfA1, one member of a sibling pair of sRNAs produced by S. dysenteriae. Unlike its nearly identical sibling molecule RyfA2, predicted to be encoded almost exclusively by non-pathogenic species, the presence of a gene encoding RyfA1, or a RyfA1-like molecule, is strongly correlated with virulence in a variety of enteropathogens. In S. dysenteriae, the over production of RyfA1 negatively impacts the virulence-associated process of cell-to-cell spread and the expression of ompC, a gene encoding a major outer membrane protein important for the pathogenesis of Shigella. Interestingly, the production of RyfA1 is controlled by a second sRNA, here termed RyfB1; the first incidence of one regulatory small RNA controlling another in S. dysenteriae or any Shigella species. Two RNAseq data sets in total. Each sample was generated by pooling three independent biological replicate RNA preps