Molecular mechanisms for central circadian pacemaker regulations

Daily rhythms in diverse activities are governed by transcriptional/translational feedback loops in clock genes. Also, it has been suggested that the circadian dynamics of intracellular signaling messengers such as Ca2+ may be critical both for the cellular physiological activities and gene transcriptional cycles. Based on these, the present study analyzed the clock gene transcriptional rhythms as well as cytosolic H+/Ca2+ in diverse models including Drosophila endocrine oscillators and SCN progenitor cells. The results demonstrated presence of clock gene oscillations but lack of apparent circadian cytosolic Ca2+ waves in these modes. Thus, the present results demonstrate cell-type specific mechanisms for the circadian rhythm generations.