Expression data from a paraquat time course experiment in wild type and SoxR deficient strains

SoxR and SoxS constitute an intracellular signal response system that rapidly detects changes in superoxide levels and modulates gene expression in E. coli. A time series microarray design was used to identify co-regulated SoxRS dependent and independent genes affected by superoxide Keywords: time course To determine the immediate transcriptional response of E. coli to superoxide, we conducted a time series assay of mRNA levels immediately following the addition of paraquat. The wild type strain MG1655 and a strain with a precise deletion in soxR was grown in EZ Rich Defined Medium, a modification of Neidhardt’s defined rich medium. When cultures reached an OD600=0.5, 250µM paraquat (PQ) was added, a concentration that triggers the SoxRS transcriptional cascade, but only has a small effect on exponential growth rate in rich media. Samples were taken immediately before exposure to PQ, and every 2 minutes after exposure, for 10 minutes.