Reconstitution of an intact clock that generates circadian DNA binding in vitro

Abstract Circadian clocks control gene expression in the complex milieu of cells. Here, we reconstituted under defined conditions in vitro the cyanobacterial circadian clock system which includes an oscillator, signal-transduction pathways, transcription factor, and promoter DNA. The system oscillates autonomously with a near 24 h period, remains phase coherent for many days, and allows real-time observation of each component simultaneously without user intervention. This reassembled clock system provides new insights into how a circadian clock exerts control over gene expression and can serve in the area of synthetic biology as a new platform upon which to build even more complexity. One Sentence Summary An autonomously oscillating circadian clock-controlled gene regulatory circuit is studied in vitro using a real-time high-throughput assay.