Hypocretin neuron-specific transcriptome profiling identifies the sleep modulator Kcnh4a
Abstract
Sleep has been conserved throughout evolution; however, the molecular and neuronal mechanisms of sleep are largely unknown. The hypothalamic hypocretin/orexin (Hcrt) neurons regulate sleep/wake states, feeding, stress, and reward. To elucidate the mechanism that enables these various functions and to identify sleep regulators, we combined fluorescence cell sorting and RNA-seq in hcrt:EGFP zebrafish. Dozens of Hcrt-neuron-specific transcripts were identified and comprehensive high-resolution imaging revealed gene-specific localization in all or subsets of Hcrt neurons. Clusters of Hcrt-neuron-specific genes are predicted to be regulated by shared transcription factors. These findings show that Hcrt neurons are heterogeneous and that integrative molecular mechanisms orchestrate their diverse functions. The voltage-gated potassium channel Kcnh4a, which is expressed in all Hcrt neurons, was silenced by the CRISPR-mediated gene inactivation system. The mutant kcnh4a(kcnh4a-/-) larvae showed reduced sleep time and consolidation, specifically during the night, suggesting that Kcnh4a regulates sleep.
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Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the guide for the laboratory use of zebrafish (Danio rerio) by Monte Westerfield, University of Oregon. All of the experiments were carried out under strict oversight of the Institutional Animal Care and Use Committee (IACUC) and with full compliance with the best criteria of animal welfare. The protocol was approved by the IACUC of Bar Ilan University (Permit Number: BIU-7-02-11).
Copyright
© 2015, Yelin-Bekerman et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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