FIGURE 1.

A, SigE overexpression in Synechocystis sp. PCC 6803. A 1.1-kb fragment of the sigE coding region was ligated with the promoter of psbAII. A kanamycin resistance cassette is located upstream of the psbAII promoter and flanked by slr2030 and slr2031. The lower panel shows the protein levels of SigE in the GT and GOX50 strains. A total of 5 μg of protein was subjected to SDS-PAGE, and SigE proteins were detected by SigE antiserum (12). B, internal control experiment for the microarray analysis using RNAs from GT cells. Total RNAs isolated from biologically independent GT cells were labeled with either Cy3 or Cy5. Each point represents the GT/GT expression ratio, and the signal intensity of the Cy3-labeled cDNAs for an ORF fragment on the array is shown. C, microarray analysis of gene expression, comparing transcript profiles of the GT and GOX50 cells. Each point represents the GOX50/GT expression ratio, and the signal intensity in the GT strain for an ORF fragment on the array is shown. Experiments were performed three times with biologically independent RNAs. The data from the means of three experiments are shown.