CAREER: FIRE Lab Investigation of Stress-induced Sleep in C. elegans

尽管睡眠具有根本的重要性，但睡眠的细胞功能仍然存在争议。睡眠被认为是跨物种的保守，近年来睡眠研究已扩展到模型生物，为遗传分析提供了强大的工具。本研究的重点是利用蛔虫C. elegans作为模式生物。主要研究者和她在加州州立大学北岭分校的本科生，一个主要为西班牙裔本科生服务的机构，已经表明，暴露于环境压力可以触发睡眠在C。优雅此外，他们证明了压力诱导的睡眠是有益的，他们已经开始确定介导这种有益效果的遗传途径的几个组成部分。 该项目扩展了这项工作，并阐明了表皮生长因子信号传导有助于应激诱导睡眠的机制。 此外，该项目使用尖端的分子技术来确定其他在调节压力诱导的睡眠中至关重要的遗传途径。这个CAREER奖项的更广泛的影响包括完全沉浸研究体验（FIRE），一个课程的主要研究者重新设计的目标是给学生一个原始的研究经验，并将这个实验室课程与研究者的睡眠研究计划相结合。由诸如有害热或组织损伤等条件触发的秀丽线虫的研究表明，细胞内稳态的扰动可能有助于睡眠驱动。应激诱导睡眠（SIS）在C。秀丽线虫可能代表了一种祖先状态，这种状态进化为在环境压力或感染后促进恢复。在更复杂的生物体中，SIS可能与昼夜节律调节相协调，以抵消已知与长时间觉醒相关的稳态扰动。这项建议的目的是表征促进SIS的遗传途径。主要研究者已经表明，压力诱导的睡眠依赖于ALA神经内分泌细胞内的表皮生长因子（EGF）受体激活;然而，压力引发EGF信号传导的机制尚不清楚。该项目的第一个目的是研究如何以及为了睡眠调节的目的，在哪些组织中监测细胞应激。由于EGF家族配体是作为跨膜前体产生的，必须经过处理才能释放可溶性配体，因此EGF依赖性睡眠可能受到应激诱导的胞外域脱落的调节。该项目的第二个目的是确定EGF在应激反应中从哪些细胞中脱落，并表征在RNAi筛选睡眠缺陷中鉴定的候选蛋白酶。该项目的第三个也是最后一个目的是通过无偏的正向遗传筛选鉴定SIS的新组分。

Despite the fundamental importance of sleep, the cellular function of sleep remains controversial. Sleep is recognized to be conserved across species, and in recent years sleep research has been extended to model organisms that provide powerful tools for genetic analysis. This project focuses on identification of genes and signaling pathways that control sleep behavior using the roundworm C. elegans as model organism. The principal investigator and her undergraduate students at California State University Northridge, a primarily undergraduate Hispanic-serving institution, have shown that exposure to environmental stresses can trigger sleep in C. elegans. Further, they demonstrated that stress-induced sleep is beneficial, and they have begun to identify several components of a genetic pathway that mediates this beneficial effect. This project expands on this work and illuminates the mechanism through which epidermal growth factor signaling contributes to stress-induced sleep. Additionally, the project uses cutting-edge molecular techniques to identify other genetic pathways critical in the regulation of stress-induced sleep. The broader impacts of this CAREER award include Full Immersion Research Experience (FIRE), a course the principal investigator redesigned with the goal of giving students an original research experience, and the integration of this lab course with the investigator's research program on sleep.The identification of a sleep state in C. elegans that is triggered by conditions, such as noxious heat or tissue damage, suggests that perturbation of cellular homeostasis may contribute to sleep drive. Stress-induced sleep (SIS) in C. elegans may represent an ancestral state that evolved to promote recovery following environmental stress or infection. In more complex organisms, SIS may be coordinated with circadian regulation, acting to counteract perturbations of homeostasis known to be associated with prolonged wakefulness. The aim of this proposal is to characterize the genetic pathways that promote SIS. The principal investigator has shown that stress-induced sleep is dependent on Epidermal Growth Factor (EGF) receptor activation within the ALA neuroendocrine cell; however, the mechanism by which stress initiates EGF signaling is not known. The first aim of this project is to investigate how and, for the purposes of sleep regulation, in which tissues cellular stress is monitored. Because EGF family ligands are produced as transmembrane precursors that must be processed for release of soluble ligand, it is likely that EGF-dependent sleep is regulated by stress-induced ectodomain shedding. The second aim of this project is to determine from which cell(s) EGF is shed in response to stress, and to characterize a candidate protease that has been identified in an RNAi screen for sleep defects. The third and final aim of this project is to identify novel components of SIS via an unbiased forward genetic screen.