The PmrA/PmrB regulatory system controls the expression of wzzfepE gene involved in the O-antigen synthesis of Salmonella enterica serovar Typhimurium

MARIA DE LAS MERCEDES PESCARETTI; FABIAN E. LOPEZ; ROBERTO MORERO; MONICA A. DELGADO

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Año: 2011 vol. 157 p. 2515 - 2521

1350-0872

The degree of polymerization of O-antigen from Salmonella enterica serovar Typhimurium is controlled by the products of the wzzst and wzzfepE genes. In the present study we investigated the role of the PmrA/PmrB regulatory system in wzzfepE transcription. We report that the direct binding of the PmrA regulator to a specific promoter site induces the expression of the wzzfepE gene. This effect increases the amount of very long (VL) O-antigen, which is required for the resistance of Salmonella to serum human complement and polymyxin B, and for the replication of the bacteria within macrophages. The results obtained here highlight functional differences between WzzfepE and Wzzst, although the genes for both proteins are regulated in a PmrA-dependent way.