A LIGHT-INDEPENDENT OSCILLATORY GENE MPER3 IN MOUSE SCN AND OVLT

A new member of the mammalian period gene family, mPer3, was isolated and its expression pattern characterized in the mouse brain, Like mPer 1, mPer2 and Drosophila period, mPer3 has a dimerization PAS domain an d a cytoplasmic localization domain. mPer3 transcripts showed a clear circadian rhythm in the suprachiasmatic nucleus (SCN). Expression of m Per3 was not induced by exposure to light at any phase of the clock, d istinguishing this gene from mPer1 and mPer2. Cycling expression of mP er3 was also found outside the SCN in the organum vasculosum lamina te rminalis (OVLT), a potentially key region regulating rhythmic gonadotr opin production and pyrogen-induced febrile phenomena. Thus, mPer3 may contribute to pacemaker functions both inside and outside the SCN.