NPAS2 As a Transcriptional Regulator of Non-Rapid Eye Movement Sleep: Genotype and Sex Interactions
NPAS2 as a transcriptional regulator of non-rapid eye movement sleep: Genotype and sex interactions Paul Franken*†‡, Carol A. Dudley§, Sandi Jo Estill§, Monique Barakat*, Ryan Thomason¶, Bruce F. O’Hara¶, and Steven L. McKnight‡§ §Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390; *Department of Biological Sciences, Stanford University, Stanford, CA 94305; ¶Department of Biology, University of Kentucky, Lexington, KY 40506; and †Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne-Dorigny, Switzerland Contributed by Steven L. McKnight, March 13, 2006 Because the transcription factor neuronal Per-Arnt-Sim-type sig- delta frequency range is a sensitive marker of time spent awake (4, nal-sensor protein-domain protein 2 (NPAS2) acts both as a sensor 7) and local cortical activation (8) and is therefore widely used as and an effector of intracellular energy balance, and because sleep an index of NREMS need and intensity. is thought to correct an energy imbalance incurred during waking, The PAS-domain proteins, CLOCK, BMAL1, PERIOD-1 we examined NPAS2’s role in sleep homeostasis using npas2 (PER1), and PER2, play crucial roles in circadian rhythm gener- knockout (npas2؊/؊) mice. We found that, under conditions of ation (9). The NPAS2 paralog CLOCK, like NPAS2, can induce the increased sleep need, i.e., at the end of the active period or after transcription of per1, per2, cryptochrome-1 (cry1), and cry2. PER and sleep deprivation (SD), NPAS2 allows for sleep to occur at times CRY proteins, in turn, inhibit CLOCK- and NPAS2-induced when mice are normally awake. Lack of npas2 affected electroen- transcription, thereby closing a negative-feedback loop that is cephalogram activity of thalamocortical origin; during non-rapid thought to underlie circadian rhythm generation.
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