麻豆传媒

The circadian clock controls the rhythmic expression of hundreds of genes in the cyanobacterium Synechococcus elongatus. The pacemaker of the clock is a core oscillator made up of three proteins: KaiA, KaiB and KaiC. Temporal information is relayed to a transcription factor, RpaA, via two kinases, CikA and SasA, that physically interact with the Kai complex.

Real-time fluorescence measurements revealed that upon receiving the same resetting signal (indicated by gray bar), the In Vitro Clock system using only the CikA kinase shows a large response, while a SasA-only clock shows a small response. The clock system containing both kinases has a balanced response to the resetting signal, which is crucial for the cyanobacterium to properly align its internal clock with the environmental cycle.