NOVEL ROLES OF TWO COMPONENT SYSTEM FOR GROWTH OF ESCHERICHIA COLI WITH HIGH CONCENTRATION OF METAL CHELATOR.

Metals are required for a bacterial vital and growth. Bacteria acquires intact metal ion and/or complex of metal ion with metallophore from environment. Two component system (TCS) is major signal transduction of bacteria and consist of a sensor kinase (SK) and a response regulator (RR). Most of RRs control gene expression to response to environmental changes. Escherichia coli has a total of 30 TCSs, of which regulate metal transporter genes in the presence or absence of metals. In this study, I show that E. coli is able to grow with high concentration of EDTA, which completely chelates metal ions in the used medium, by three TCSs. First, I isolated the non-SK strain of E. coli, knockout all of 30 species of SK genes on its genome, by HoSeI method, the novel genome editing technology developed here. The non-SK strain did not grow with high concentration of EDTA in comparison with the parent strain. Growth experiments of the several SK knockout strains reveal that E. coli require for the phoQ, envZ, and qseC genes to grow in high EDTA concentration. In good agreement with the requirement of two SK genes, phoQ and envZ genes, the phoP and ompR genes, coding the cognate RRs for them, were also required. Among genes induced by PhoP, the slyB and mgtA genes also required to grow in high EDTA concentration. These results speculate that PhoQ-PhoP and EnvZ-OmpR are essential for the growth of E. coli in high EDTA concentration and regulate genes involved in acquisition of complex of metal ion with metallophore