title: Translational profiling of hypocretin neurons identifies candidate molecules for sleep regulation.
abstract: Hypocretin (orexin; Hcrt)-containing neurons of the hypothalamus are essential for the normal regulation of sleep and wake behaviors and have been implicated in feeding, anxiety, depression, and reward. The absence of these neurons causes narcolepsy in humans and model organisms. However, little is known about the molecular phenotype of these cells; previous attempts at comprehensive profiling had only limited sensitivity or were inaccurate. We generated a Hcrt translating ribosome affinity purification (bacTRAP) line for comprehensive translational profiling of all ribosome-bound transcripts in these neurons in vivo. From this profile, we identified >6000 transcripts detectably expressed above background and 188 transcripts that are highly enriched in these neurons, including all known markers of the cells. Blinded analysis of in situ hybridization databases suggests that ~60% of these are expressed in a Hcrt marker-like pattern. Fifteen of these were confirmed with double labeling and microscopy, including the transcription factor Lhx9. Ablation of this gene results in a >30% loss specifically of Hcrt neurons, without a general disruption of hypothalamic development. Polysomnography and activity monitoring revealed a profound hypersomnolence in these mice. These data provide an in-depth and accurate profile of Hcrt neuron gene expression and suggest that Lhx9 may be important for specification or survival of a subset of these cells.
authors: Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors: Jasbir
authors: J
authors: Dalal
authors: Jee Hoon
authors: JH
authors: Roh
authors: Susan E
authors: SE
authors: Maloney
authors: Afua
authors: A
authors: Akuffo
authors: Samir
authors: S
authors: Shah
authors: Han
authors: H
authors: Yuan
authors: Brie
authors: B
authors: Wamsley
authors: Wendell B
authors: WB
authors: Jones
authors: Cristina
authors: C
authors: de Guzman Strong
authors: Paul A
authors: PA
authors: Gray
authors: David M
authors: DM
authors: Holtzman
authors: Nathaniel
authors: N
authors: Heintz
authors: Joseph D
authors: JD
authors: Dougherty
mesh_terms: D000818:Animals; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D060850:LIM-Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides; D000068797:Orexins; D011401:Promoter Regions, Genetic / Q000235:genetics; D040081:Protein Array Analysis; D012890:Sleep / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D060850:LIM-Homeodomain Proteins; C117058:Lhx9 protein, mouse; D009479:Neuropeptides; D000068797:Orexins; D014157:Transcription Factors