Genes controlling circadian rhythm are widely distributed in cyanobacteria

The kaiABC gene cluster is important for maintaining circadian rhythms in t he cyanobacterium Synechococcus PCC 7942. An extensive PCR-based survey of phylogenetically diverse cyanobacteria was conducted using degenerate prime rs designed to identify the presence of the kaiC gene. Hybridization and se quence analyses showed that the observed amplification products had a high degree of similarity to kaiC. Forty cyanobacterial strains possessed kaiC r elated sequences, suggesting that a clock system is universal among cyanoba cteria. (C) 2000 Federation of European Microbiological Societies. Publishe d by Elsevier Science B.V. All rights reserved.