Chronobiology/Circadian Disorders CIRCADIAN CLOCK PROTEIN PERIOD3 CONTRIBUTES TO SLEEP HOMEOSTASIS THROUGH HISTAMINE AND GABA SIGNALING IN ZEBRAFISH H. Wang. Center for Circadian Clocks, Soochow University, Suzhou, China Introduction: The zebrafish (Danio rerio) has figured prominently as a vertebrate model for studying circadian clocks and sleep. It is known that both the homeostatic process (S) and the circadian process (C) contribute to regulation of sleep homeostasis. While we have a good understanding of circadian regulation, relatively little is known about molecular mecha- nisms underlying circadian regulation of sleep homeostasis and/or inter- action between the circadian clock system and sleep. Materials and methods: TALEN, a genome-editing tool, was used to generate a number of zebrafish per3 mutant lines. Behavioral assays, qRT- PCR, luciferase reporter assays, and RNA-seq were used to characterize zebrafish period3 (per3) null mutants. Results: Locomotor assays showed that per3 mutant fish display 0.5-hour shortened period and approximately 3-hour phase advance compared with wild types under constant dark, and are completely arrhythmic under constant light; and also per1a, per1b and per2 are down-regulated in per3 mutant fish; indicating that per3 is essential for zebrafish circadian regu- lation. Intriguingly, per3 mutant fish display less sleep time, reduced arousal threshold and difficulty to restore sleep after sleep deprivation. As shown by ELISA, the GABA level is reduced while the histamine level is increased in per3 mutant fish at night-time, indicating that the disturbed sleep pattern of per3 mutant fish may be resulted from altered levels of endogenous GABA and histamine. Deep sequencing-based transcriptome analysis leads us to focus on two candidate genes, GABA A receptor gene rho2a and his- tamine decarboxylase gene hdc, both up-regulated in the per3 mutant fish. Luciferase reporter assays showed that both rho2a and hdc are circadian clock-controlled genes and Per3 negatively regulates their expression. Conclusions: Taken together, these results ascertain Per3's essential roles in the zebrafish circadian system, demonstrate that Per3 acts through both histamine signaling and GABA signaling to contribute to sleep regulation, and provide an ideal sleep disorder vertebrate model for drug screen and pathogenesis analysis. Acknowledgements: This work was supported by the grants from Na- tional Basic Research Program of China (973 Program) (2012CB947600) and the National Natural Science Foundation of China (NSFC) (31030062, 81070455). Narcolepsy EVIDENCE FOR A NARCOLEPSY SPECTRUM DISORDER IN FAMILY MEMBERS OF PATIENTS WITH TYPE 1 NARCOLEPSY P. Wang 1 , H. Yan 1 , F. Han 1 , L. Lin 2 , E. Mignot 2 . 1 Peking University People's Hospital, Beijing, China; 2 Stanford University Center for Sleep Science and Medicine, Palo Alto, United States Introduction: The existence of a narcolepsy spectrum has been suggested in family members of patients with narcolepsy, but this has never been confirmed through systematic evaluation using sleep study and hypocretin evaluation. Materials and methods: Narcolepsy cases (n¼496) were identified among 5,462 patients visiting the Peking University People's Hospital Sleep Center from 09/01/2012 to 12/03/2014, including 307 children (< 18y) meeting in- clusion criteria. Two hundreds and one families (66%) with at least one parent available accepted further evaluation. The resulting 378 parents under- went HLA typing, polysomnography, multiple sleep latency test (MSLT), and questionnaire evaluations. CSF hypocretin-1 was tested in 4 subjects. Three subjects with a positive MSLT underwent a second MSLT for confirmation. Results: We found 3 parents (0.8%) with narcolepsy-cataplexy (100% DQB1*06:02) and 9 with a positive MSLT but no cataplexy (78% DQB1*06:02). In the 6 parents tested for CSF hypocretin-1 level, two cases (one with and one without cataplexy) had low CSF hypocretin-1 (110 pg/ ml), and one case without cataplexy had intermediary level (153 pg/ml). Repeat PSG-MSLT was positive in 2 of 3 relatives retested. Further analysis suggests that between 2 (0.5%) and 6 (1.6%) of the 9 subjects with narco- lepsy but no cataplexy have hypocretin deficiency. Conclusions: In parents of patients with cataplexy, 0.8% has narcolepsy- cataplexy, and an equivalent or larger number (0.5-1.6%) have mild type 1 narcolepsy without cataplexy due to hypocretin deficiency. These results substantiate the hypothesis that some subjects with hypocretin deficiency do not have cataplexy, and that subjects with cataplexy are the extreme of a disease spectrum. Mild symptomatology may explain why these subjects are rarely diagnosed in sleep centers. Acknowledgements: This work was supported by research grants from the Ministry of Science and Technology (2015CB856405), NSFC((81420108002, 81670087, 81300061, 81570083), Beijing Natural Science Foundation (7152153) and NIH grant (P50 NS-23624). We thank the parents and most importantly the children for their participation. Chronobiology/Circadian Disorders THE ROLE OF NUCLEAR RECEPTORS IN REGULATING CIRCADIAN PERIOD T. Wang , Y. Xu. CAM-SU Genomic Resource Center, Soochow University, Suzhou, China In mammals, circadian oscillation depends on the complex transcriptional network comprised of the interaction among core clock genes via E box, RRE, D box and other DNA elements. As important clock genes, the nuclear receptor genes Rev-Erbs and RORs participate in clock feedback loop by regulating RRE activity, which is essential for maintaining clock robust- ness. In addition to Rev-Erbs and RORs, most clock controlled nuclear re- ceptors may also be involved in the regulation of circadian rhythms. We comprehensively investigated the influences of nuclear receptor knockout on circadian rhythms using CRISPR-CAS9 system. We found ablation of several nuclear receptors significantly changes clock period in human cells. While these nuclear receptors are transcriptionally clock controlled. We further predicted and found many potential nuclear receptor binding motifs near TSS of human core clock genes. Our data implicate a multi- circuit nod by nuclear receptors stabilizing the circadian transcription- translation feedback loop (TTFL) and coupling circadian clock with diurnal physiological changes. Behavior, Cognition and Dreaming EXPERIENTIAL EMOTION REGULATION VERSUS COGNITIVE REAPPRAISAL: EFFECTS ON AFFECT AFTER STRESS AND FOLLOW-UP SLEEP PHYSIOLOGY Y. Wang 1 , L. Depoortere 2 , L. Carlo Bulnes 2 , D. Dong 3 , M. Dhar 4 , D. Marinazzo 5 , M. Vandekerckhove 6 . 1 Faculty of Psychology and Educational Sciences, VUB, Brussel, Belgium; 2 Department of Experimental and Applied Psychology, Vrije Universiteit Brussel, Brussels, Belgium; 3 Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China; 4 Department of Experimental and Applied Psychology, Vrije Universiteit Brussel, Brussel, Belgium; 5 University of Gent, Gent, Belgium; 6 Vrije Universiteit Brussel, Brussel, Belgium Introduction: The interesting idea that emotion regulation (ER) plays a key role in modulating effects of stress on sleep, however, has received few research attention. Research findings suggest that emotion regulation plays a key role in the precipitating and perpetuating effects of stress on sleep (Vandekerckhove & Cluydts, 2010). In this study, we compared the impact of an induced  experiential approach  , defined as stressing the awareness of our feelings by paying attention to our bodily felt parts in an acceptable and welcoming way (Vandekerckhove & Kestemong, 2012), versus a  cognitive approach  by cognitive reappraisal, defined as reinter- preting a situation in order to eliminate or change one's emotions about it (Gross, 1998), on sleep physiology. Materials and methods: 43 participants were recruited and randomly assigned to 3 groups: 15, 13, 15 for experiential, reappraisal and neutral non-specific regulation respectively. 20-Item Toronto Alexithymia Scale (TAS) and Emotional Approach Coping Scale are used to address the in- dividual difference. All participants spend 3 nights (adaption, baseline and experimental night) in the sleep lab for 8 hours. An emotional failure in- duction was used to trigger stress, after which emotion regulation was induced twice (writing task). Subject negative affect was obtained by the Abstracts / Sleep Medicine 40 (2017) e186ee363 e343