DNA microarray analysis of circadian gene expression in the cyanobacterium Synechococcus elongatus sp. PCC 7942

Abstract

Cyanobacteria are the simplest organisms known to have a circadian clock. A random promoter-trap experiment in Synechococcus elongatus sp. PCC 7942 demonstrated circadian rhythms in the activities of almost all gene promoters. It seems plausible that the cyanobacterial clock system regulates basic transcriptional machinery or a process closely linked to it. Here we show physiological significance of circadian gene expression by using high-density DNA microarrays (Affymetrix Gene Chip) of S. elongatus 7942. Gene expressions of a whole genome were analyzed every 4 hours during 52 hours of continuous culture. It will be discussed that circadian gene expression is involved in controlling physiological processes in the cyanobacterium.