No Promoter Left Behind: Global Circadian Gene Expression in Cyanobacteria

The KaiABC oscillator in cyanobacteria may regulate global gene expression patterns through rhythmic changes in chromosome status.

• Cyanobacteria display robust daily rhythms controlled by a circadian clock system that shares similarities with eukaryotic clocks.
• The cyanobacterial clock differs from eukaryotic systems by globally regulating gene expression without reliance on specific clock gene promoters.
• A novel oscilloid model suggests that the KaiABC oscillator mediates topological changes in the cyanobacterial chromosome.
• These chromosome changes may underlie the observed global transcription rhythms in cyanobacteria.
• The proposed model could represent one of several mechanisms by which circadian clocks regulate gene expression, applicable to eukaryotes as well.

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