title: cDNA microarray assessment of early gene expression profiles in Escherichia coli cells exposed to a mixture of heavy metals.
abstract: Many contaminated sites are characterized by the presence of different metals, thus increasing the complexity of toxic responses in exposed organisms. Within toxicogenomics, transcriptomics can be approached through the use of microarrays aimed at producing a genetic fingerprint for the response of model organisms to the presence of chemicals. We studied temporal changes in the early gene expression profiles of Escherichia coli cells exposed to three metal doses of a polymetallic solution over three exposure times, through the application of cDNA microarray technology. In the absence of metals, many genes belonging to a variety of cellular functions were up- and down-regulated over time. At the lowest metal dose, an activation of metal-specific transporters (Cus and ZraP proteins) and a mobilization of glutathione transporters involved in metal sequestration and trafficking was observed over time; this metal dose resulted in the generation of ROS capable of stimulating the transcription of Mn-superoxide dismutase, the assembly of Fe-S clusters and the synthesis of cysteine. At the intermediate dose, an overexpression of ROS scavengers (AhpF, KatG, and YaaA) and heat shock proteins (ClpP, HslV, DnaK, and IbpAB) was observed. Finally, at the highest dose, E. coli cells showed a repression of genes related with DNA mutation correctors (MutY glycopeptidases).
authors: NEIKER-Tecnalia, Department of Ecology and Natural Resources, Soil Microbial Ecology Group, c/Berreaga 1, E-48160, Derio, Spain.
authors: María T
authors: MT
authors: Gómez-Sagasti
authors: José M
authors: JM
authors: Becerril
authors: Iker
authors: I
authors: Martín
authors: Lur
authors: L
authors: Epelde
authors: Carlos
authors: C
authors: Garbisu
mesh_terms: D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D019216:Metals, Heavy / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis; D014158:Transcription, Genetic; D059467:Transcriptome
chemical_list: D029968:Escherichia coli Proteins; D019216:Metals, Heavy