Genomic responses to copper in Synechocystis

Analysis of genome-wide gene expression patterns in response to copper in WT and COPR mutant in the cyanobacterium Synechocystis sp PCC 6803. Here we have used microarrays to interrogate the global responses to copper additions at non-toxic (0.3 micromolar) and toxic concentrations (3 micromolar) of copper in WT and in a mutant in the copR gene. Addition of the non-toxic copper concentration stimulated the metabolism and induced the switch in the use from cyitochrome c6 to plastocyanin. In contrast, high copper addition induced a stress response and affected the metabolism of several other metals. This included repression of ribosomal, photosynthetic and metabolic genes and induction of chaperones and antioxidant enzymes genes. Finally CopRS seems to control only the expression of the copMRS and copBAC operons as all other genes that were differentially expressed by copper seemed to be unaffected in copR strains. Cells treated with 0.3 µM or 3µM copper for 1h.