Global transcriptional response to copper of Enterococcus faecalis wild-type and copY mutant

We examined the whole-genome transcriptional response of E. faecalis wild-type (WT) and copy mutant cells exposed to non toxic Cu excess. The analysis was focused in those genes which changed significantly their expression levels in the Cu-treated cells when compared to their untreated counterparts. The results indicated that after 3 h at 0.5 mM CuSO4, WT cells exhibited a significant increment of Cu content and the induction of three genes of cop operon along with other 142 genes. The comparison with the copY mutant exposed to Cu showed an extensive overlapping of transcriptional changes suggesting that other transcription factors may be mediating the response to Cu. Associated manuscript The global response of Enterococcus faecalis to copper exposure RNA was extracted from four different culture conditions: 1) untreated WT cells; 2) Cu-treated WT cells; 3) untreated copy mutant cells; and 4) Cu-treated copy mutant cells. Each array contained 72,000 oligonucleotides 60-mer, with an average of 11 oligos designed for the 3,114 open reading frames of E. faecalis V583, that represent twice the genome of the bacterium (two technical replicates per arrays). For wild type and copY mutant four independent hybridizations (two biological replicates per treatment paired with their respective controls) were performed. Gene expression data from WT cells was compared to Cu-treated WT cells; and data from copY mutant cells were compared to Cu-treated copY mutant cells.