Living organisms on the earth synchronize their activity to a 24-hour light and dark cycle generated by the rotation of the earth. This biological rhythm is called the circadian rhythm, which means “approximately one day.” Each cell within unicellular organisms, cultured cell lines, and cells composing tissues has its own circadian clock.
In animals, the circadian rhythm of cells in tissues is synchronized by the suprachiasmatic nucleus (SCN) located in the hypothalamus via nerves or humoral signals. The SCN clock is called the central clock and that within each tissue is called the peripheral clock.
Recently, the molecular mechanism for the oscillation of the circadian rhythm has been elucidated and the approximately-24-hour rhythm was found to be generated by a transcription–translation feedback-loop of clock genes expressed by almost all cells. In particular, BMAL1, CLOCK, PERs, and CRYs play central roles in the oscillation of the circadian rhythm and rhythmically regulate the expression of downstream genes (hereinafter referred to as clock-controlled genes [CCGs]).
Approximately 10% of all genes expressed in the liver and heart are considered CCGs. Stable oscillation of the expression of clock genes regulates numerous life activities, including the approximately-24-hour sleep/awake cycle, blood pressure, body temperature, and hormone secretion. Disruption of the circadian rhythm and polymorphisms in circadian rhythm-related genes are reportedly associated with various diseases, such as hypertension, diabetes, and sleep disturbance. Clock genes have been thoroughly investigated, not only as direct targets for drug discovery, but also from the standpoint of drug metabolizing efficiency. MBL offers a wide choice of antibodies against circadian rhythm-related genes that can be used with WB and ChIP. Please take this opportunity to try these products.