Fris, Megan E.Broach, William H.Klim, Sarah E.Coschigano, Peter W.Carroll, Ronan K.Caswell, Clayton C.Murphy, Erin R.2017-09-202017-09-202017-01-26Fris, M.E.; Broach, W.H.; Klim, S.E.; Coschigano, P.W.; Carroll, R.K.; Caswell, C.C.; Murphy, E.R. Sibling sRNA RyfA1 Influences Shigella dysenteriae Pathogenesis. Genes 2017, 8, 50.http://hdl.handle.net/10919/79306Small regulatory RNAs (sRNAs) of <em>Shigella dysenteriae</em> 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 <em>S. dysenteriae</em>. 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 <em>S. dysenteriae</em>, the overproduction of RyfA1 negatively impacts the virulence-associated process of cell-to-cell spread as well as the expression of <em>ompC</em>, 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 <em>S. dysenteriae</em> or any <em>Shigella</em> species.application/pdfenCreative Commons Attribution 4.0 InternationalShigellasRNApathogenesisriboregulatorssiblingOmpCArticle - Refereed2017-09-20https://doi.org/10.3390/genes8020050