Abstract
Cyanobacteria have been known to drastically change gene expression pattern in response to change in photic environment suggesting the presence of machinery for transcriptional regulation in response to light stimulus. In order to identify such components, we carried out DNA microarray analysis in mutants of transcription factor whose expression was light responsive. In consequence, disruption of light-repressive slr0741 (phoU-homolog) and light-inducible sll1594 (ndhR) were shown to attenuate responsiveness to light in subset of gene expression. Disruption of slr0741 reduced induction rate of 57 genes including rbc operon, ribosomal protein genes and repression rate of ten genes including dnaJ. Disruption of sll1594 reduced induction rate of four genes including ribosomal protein genes and repression rate of 22 genes including trxM and nblA. This result suggested that slr0741 and sll1594 function as an activator and a repressor of gene expression upon dark to light transition.
