Motility modulation by the small non-coding RNA SroC inSalmonellaTyphimurium

Abstract

Bacterial regulatory networks of gene expression include the interaction of diverse types of molecules such as the small non-coding RNAs (sRNAs) and their cognate messenger RNAs (mRNAs). In this study, we demonstrated that the Salmonella Typhimurium sRNA SroC is significantly expressed between the late-exponential and stationary phase of growth in an rpoS-dependent manner. The expression of flagellar genes predicted as targets of this sRNA was quantitatively analyzed in both a ΔsroC mutant and a SroC-overexpressing (pSroC) strain. Deletion of sroC increased flagellar gene expression (i.e. flhBAE and fliE). Conversely, overexpression of SroC reduced flhBAE and fliE expression. These observations correlated with phenotypic evaluation of motility, where sroC deletion slightly increased motility, which in turn, was drastically reduced upon overexpression of SroC. The effects of deletion and overexpression of sroC in biofilm formation were also examined, where the ΔsroC and pSroC strains exhibited a reduced and increased ability to form biofilm, respectively. Furthermore, electron microscopy revealed that the wild-type strain overexpressing SroC had a non-flagellated phenotype. Taken together, our results showed that S. Typhimurium sRNA SroC modulates the flagellar synthesis by down-regulating the expression of flhBAE and fliE genes.

GcvB small RNA uses two distinct seed regions to regulate an extensive targetome

“…This suggests a lower GcvB‐mediated repression of all target mRNAs. In S. Typhimurium, SroC sRNA is mainly produced during late‐exponential and stationary phase of growth (Fuentes et al ., ). As in E. coli (Fig.…”

“…Recently, SroC was depicted as mainly produced during late‐exponential and stationary phase of growth, responding to the sigma factor σ S in S. Typhimurium (Fuentes et al ., ). Still, signals triggering SroC release from the 3’UTR of gltI mRNA are poorly characterized.…”

Novel DNA Binding and Regulatory Activities for σ 54 (RpoN) in Salmonella enterica Serovar Typhimurium 14028s

“…ABSTRACT The variable sigma () subunit of the bacterial RNA polymerase (RNAP) holoenzyme, which is responsible for promoter specificity and open complex formation, plays a strategic role in the response to environmental changes. Salmonella enterica serovar Typhimurium utilizes the housekeeping 70 and five alternative sigma factors, including 54 . The 54 -RNAP differs from other -RNAP holoenzymes in that it forms a stable closed complex with the promoter and requires ATP hydrolysis by an activated cognate bacterial enhancer binding protein (bEBP) to transition to an open complex and initiate transcription.…”

“…Salmonella enterica serovar Typhimurium utilizes the housekeeping 70 and five alternative sigma factors, including 54 . The 54 -RNAP differs from other -RNAP holoenzymes in that it forms a stable closed complex with the promoter and requires ATP hydrolysis by an activated cognate bacterial enhancer binding protein (bEBP) to transition to an open complex and initiate transcription. In S. Typhimurium, 54 -dependent promoters normally respond to one of 13 different bEBPs, each of which is activated under a specific growth condition.…”

In silico prediction and expression profile analysis of small non-coding RNAs in Herbaspirillum seropedicae SmR1

“…Our data suggest that many sRNAs may be involved in the posttranscriptional regulation of genes related to the adaptation and endophytic colonization of H. seropedicae SmR1 in plants. Further investigation is required to determine if some sRNAs may be related to flagella synthesis and bacterial motility as shown in other organisms [83,84].…”