sentences:  In the brain, NPAS2 functions as a generator and maintainer of mammalian circadian rhythms.More specifically, NPAS2 is an activator of transcription and translation of core clock and clock-controlled genes through its role in a negative feedback loop in the suprachiasmatic nucleus (SCN), the brain region responsible for the control of circadian rhythms.The mammalian and mouse "Npas2" gene was first sequenced and characterized in 1997 Dr. Steven McKnight's lab and published by Yu-Dong Zhou et al.