The YbjN regulon in Escherichia coli

YbjN, an enterobacteria-specific protein, is a multicopy suppressor of ts9 temperature sensitivity in Escherichia coli. Microarray study revealed that the expression level of ybjN was inversely correlated with the expression of flagellar, fimbrial and acid resistance genes. Over-expression of ybjN significantly down-regulated genes involved in the citric acid cycle, glycolysis, the glyoxylate shunt, oxidative phosphorylation, and amino acid and nucleotide metabolism. On the other hand, over-expression of ybjN up-regulated toxin-antitoxin modules, the SOS responsive pathway, cold shock proteins and starvation-induced transporter genes. Our results collectively suggest that YbjN may play important roles in regulating bacterial multicellular behaviors, metabolism and survival under various stress conditions in Es. coli. A total of 8 samples were analyzed: E. coli wild type strain (2 replicates); E. coli ybjN mutant strain (3 replicates); E. coli ybjN over-expression strain (3 replicates).