Transcriptional response of E. coli to TPEN

DNA microarrays were used to probe the transcriptional response of E. coli to N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN). Fifty-five transcripts were significantly up-regulated including all of the genes that are regulated by Zur and many genes regulated by Fur. In these same TPEN-treated cells, forty-six transcripts were significantly down-regulated. Keywords: E. coli, TPEN, zinc To identify genes that are differentially-expressed in response to TPEN, E. coli BL21(DE3) cells grown in minimal medium until the cultures reached mid-log phase. TPEN was introduced and the cells were cultured for 5 hours; this time was chosen so that the results would correspond to previous transcriptional response studies with excess Zn(II). The cultures containing 5 uM TPEN were analyzed with DNA microarrays (E. coli K12 V2 array slides from MWG-BIOTECH), and the results were compared to those from E. coli cells grown in minimal medium containing no TPEN. A minimum of six slides was used for each experiment (3 slides with one combination of Cy3 and Cy5 dyes and 3 slides with swapped dyes).