Clock gene protein mPER1 is rhythmically synthesized and under cAMP control in the mouse pineal organ

The mammalian clock gene Per1 is an important element of endogenous oscilla tors that control daily rhythms in central and peripheral tissues. Although such autonomous clock function is lost in the mammalian pineal gland durin g evolution, mPer1 mRNA and mPER1 protein were found to be strongly elevate d in the mouse pineal organ during the dark period compared to daytime valu es. In vitro studies showed that mPer1 mRNA and mPER1 protein in mouse pine al gland are induced following the activation of a signalling pathway of fu ndamental importance for pineal physiology, the norepinephrine/cAMP/phospho CREB cascade. mPER1 may function in the mouse pineal gland as a time-measur ing molecule to participate in regulating rhythmic cellular responses in vi vo.