Altered Yersinia pestis virulence is associated with the small regulatory RNA HmsA encoded on the plasmid pPCP1.

Aim: The aim of this study was to access the effect of HmsA, a 65-nt small regulatory RNA encoded by the pPCP1 plasmid, on Yersinia pestis virulence. Materials & methods: Survival and the competition index were determined in mice infected with wild-type Y. pestis and an hmsA deletion mutant. RNA-seq was used to identify HmsA-regulated genes.

Results

HmsA deletion enhanced Y. pestis virulence. However, there was no overlap between 18 upregulated genes associated with pathogenicity and potential direct HmsA targets, based on gene expression screening after HmsA-pulse overexpression.

Conclusion

HmsA inhibits Y. pestis virulence, but this effect may be mediated by indirect effects on pathogenesis, iron homeostasis and/or other cellular processes.