A Salmonella Typhi RNA thermosensor regulates virulence factors and innate immune evasion in response to host temperature.

Autor: Susan M Brewer, Christian Twittenhoff, Jens Kortmann, Sky W Brubaker, Jared Honeycutt, Liliana Moura Massis, Trung H M Pham, Franz Narberhaus, Denise M Monack
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: PLoS Pathogens, Vol 17, Iss 3, p e1009345 (2021)
Druh dokumentu: article
ISSN: 1553-7366
1553-7374
DOI: 10.1371/journal.ppat.1009345
Popis: Sensing and responding to environmental signals is critical for bacterial pathogens to successfully infect and persist within hosts. Many bacterial pathogens sense temperature as an indication they have entered a new host and must alter their virulence factor expression to evade immune detection. Using secondary structure prediction, we identified an RNA thermosensor (RNAT) in the 5' untranslated region (UTR) of tviA encoded by the typhoid fever-causing bacterium Salmonella enterica serovar Typhi (S. Typhi). Importantly, tviA is a transcriptional regulator of the critical virulence factors Vi capsule, flagellin, and type III secretion system-1 expression. By introducing point mutations to alter the mRNA secondary structure, we demonstrate that the 5' UTR of tviA contains a functional RNAT using in vitro expression, structure probing, and ribosome binding methods. Mutational inhibition of the RNAT in S. Typhi causes aberrant virulence factor expression, leading to enhanced innate immune responses during infection. In conclusion, we show that S. Typhi regulates virulence factor expression through an RNAT in the 5' UTR of tviA. Our findings demonstrate that limiting inflammation through RNAT-dependent regulation in response to host body temperature is important for S. Typhi's "stealthy" pathogenesis.
Databáze: Directory of Open Access Journals
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