kaiC is a gene belonging to the kaiABC gene cluster. The kaiABC gene cluster is a group of genes, consisting of '' kaiA, kaiB, ''and kaiC, globally regulating circadian gene expression in cyanobacteria. Regulation of kaiABC expression is essential for circadian rhythmicity, and is particularly important for regulating cyanobacteria processes such as nitrogen fixation, photosynthesis, and cell division. Using bacterial luciferase as a reporter for gene expression, studies have shown that, similar to Drosophila, mouse, and Neurospora clock models, the cyanobacteria circadian clock, controlled by kaiABC regulation, is also based on a transcription translation feedback loop(TTFL). Within its gene cluster, kaiC codes for the regulator, KaiC protein, which not only suppresses ''kaiBC when overexpressed, ''but also suppresses circadian expression of all genes in the cyanobacterial genome.