Metal-ion tolerance in Escherichia coli: analysis of transcriptional profiles by gene-array technology

School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, UK 1 Author for correspondence: Andrew P. Morby. Tel: +44 2920 874128. Fax: +44 2920 874116. e-mail: morby{at}cf.ac.uk Escherichia coli was adapted to grow in medium containing substantially elevated concentrations of either Zn(II), Cd(II), Co(II) or Ni(II). Whole-genome transcriptional profiles were generated from adapted strains and analysed for significant alteration in transcript abundance with reference to a wild-type strain. Similar alterations in specific message levels were observed for strains adapted to the four metal ions. One unexpected trend was the increase in transcript level of genes involved in transposition of IS elements, particularly insA . Subsequent expression of insA-7 from a heterologous promoter in E. coli conferred tolerance to Zn(II). Keywords: Escherichia coli , metal ion, adaptation, gene array, insA