THE DNA-BINDING PROTEIN DPS FUNCTIONS AS A GLOBAL REGULATOR IN STARVED SALMONELLA ENTERICA SEROVAR ENTERITIDIS DURING STARVATION

Abstract

-The DNA binding protein of stationary phase cells (Dps)-first discovered in starved Escherichia coli-is capable of providing protection to cells during exposure to various environmental assaults. Its ability to do so is based on three intrinsic properties of the protein: DNA binding, iron sequestration, and its ferroxidase activity. Proteomic studies have lead to the inference of a regulatory role for Dps as well; however, the ability of Dps to serve as a global regulator during nutritional deprivation has yet to be directly examined. In this study, we utilized microarray analysis and quantitative real-time PCR to establish direct evidence for a regulatory role of Dps in starved Salmonella enterica serovar Enteritidis. The results of our microarray screening revealed over 150 genes significantly up or down regulated in starved cells lacking functional Dps protein. Also, we identified a small subset of genes regulated by Dps that are important for the induction of hydrogen peroxide, iron, and acid resistance. The fact that it positively regulates genes important for stress resistance further solidifies Dps as a virulence regulator in S. enteritidis; for resistance to such cytotoxic conditions is likely to translate into enhanced survivability and virulence within infected hosts.