Circadian regulation of c-MYC in mice

Significance A molecular clock controls circadian rhythmicity in mammals. The interplay of the clock with cellular growth and development is of interest regarding possible connections between cancer and clock disruption. The c-MYC oncoprotein is a transcriptional activator that has been reported to control and be controlled by the clock. We have used knockout mice mutated in genes controlling either the negative or positive arm of the molecular clock to clarify the role of the clock in c-MYC regulation. Results with both types of mutant mice consistently show that the clock controls c-MYC protein levels by controlling expression of the c-Myc oncogene. These findings will aid in understanding the interplay of the clock and clock disruption on cell growth control and cancer.