Transcriptional regulation of the Salmonella enterica std fimbrial operon by the RcsCDB system

FARIZANO, JUAN V.; GARCÍA-PASTOR, LUCIA; CASADESÚS, JOSEP; DELGADO, MONICA A.

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Año: 2019 vol. 165 p. 1245 - 1250

1350-0872

In Salmonella enterica serovar Typhimurium, the RcsCDB regulatory system controls the expression of genes involved in synthesis of colanic acid, formation of flagella and virulence. Here, we show that activation of the RcsCDB system downregulatesexpression of std, an operon that encodes fimbriae involved in Salmonella attachment to the mucus layer in the large intestine.Bioinformatic analysis predicts the existence of an RcsB-binding site located 180bp upstream to the +1 transcription start siteof the std promoter, and electrophoretic mobility shift assays confirm that RcsB binds the std promoter region in vitro. This studyadds RcsB to the list of regulators of std transcription and provides an example of modulation of fimbriae synthesis by a signaltransduction system.