A trans-acting leader RNA from a Salmonella virulence gene

Eunna Choi, Yoontak Han, Yong Joon Cho, Daesil Nam, Eun Jin Lee

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Bacteria use flagella to move toward nutrients, find its host, or retract from toxic substances. Because bacterial flagellum is one of the ligands that activate the host innate immune system, its synthesis should be tightly regulated during host infection, which is largely unknown. Here, we report that a bacterial leader mRNA from the mgtCBR virulence operon in the intracellular pathogen Salmonella enterica serovar Typhimurium binds to the fljB coding region of mRNAs in the fljBA operon encoding the FljB phase 2 flagellin, a main component of bacterial flagella and the FljA repressor for the FliC phase 1 flagellin, and degrades fljBA mRNAs in an RNase E-dependent fashion during infection. A nucleotide substitution of the fljB flagellin gene that prevents the mgtC leader RNA-mediated down-regulation increases the fljB-encoded flagellin synthesis, leading to a hypermotile phenotype inside macrophages. Moreover, the fljB nucleotide substitution renders Salmonella hypervirulent, indicating that FljB-based motility must be compromised in the phagosomal compartment where Salmonella resides. This suggests that this pathogen promotes pathogenicity by producing a virulence protein and limits locomotion by a trans-acting leader RNA from the same virulence gene during infection.

Original languageEnglish
Pages (from-to)10232-10237
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number38
Publication statusPublished - 2017 Sept 19
Externally publishedYes


  • Flagellin
  • Trans-acting leader RNA
  • mgtC

ASJC Scopus subject areas

  • General


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