Transcriptional autoregulation of the RcsCDB phosphorelay system in Salmonella enterica serovar Typhimurium

MARÍA DE LAS MERCEDES PESCARETTI; FABIÁN E. LÓPEZ; ROBERTO D. MORERO; MÓNICA A. DELGADO

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Lugar: Londres - Reino Unido; Año: 2010 vol. 156 p. 3513 - 3521

1350-0872

The RcsCDB (Rcs) phosphorelay system is involved in the regulation of many envelop genes like those responsible for capsule synthesis, flagella production and O-antigen chain length, as well as in other cellular activities of several enteric bacteria. This system is composed of three proteins: the sensor RcsC, the response regulator RcsB and the phospho-transfer intermediary protein, RcsD. Previously, we reported two important issues about this system: a) the rcsB gene expression is under the control of PrcsDB and PrcsB promoters, and b) the rcsD gene transcription decreased when the bacteria reach high levels of RcsB regulator. In the present work, we demonstrate that RcsB protein represses the rcsD gene expression by binding directly to the PrcsDB promoter, negatively autoregulating the Rcs system. Furthermore, we report the physiological role of the RcsB regulator which was able to modify the bacterial swarming behavior, when it is expressed under the control of the PrcsB promoter.