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

尽管睡眠很重要，但睡眠的细胞功能仍然存在争议。睡眠被认为是跨物种守恒的，近年来，睡眠研究已扩展到为遗传分析提供强大工具的模型生物。该项目以线虫为模式生物，致力于识别控制睡眠行为的基因和信号通路。这位首席研究员和她在加州州立大学北岭分校的本科生已经证明，暴露在环境压力下会引发线虫的睡眠。北岭大学是一所主要面向西语裔本科生的机构。此外，他们还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一有益效果的遗传途径的几个组成部分。该项目对这项工作进行了扩展，阐明了表皮生长因子信号对应激诱导睡眠的作用机制。此外，该项目使用尖端分子技术来识别在压力诱导睡眠调节中至关重要的其他遗传途径。这一职业奖项的更广泛影响包括首席研究员重新设计的一门课程--完全沉浸研究体验(FIRE)，目的是让学生获得原创的研究体验，以及将这门实验室课程与研究人员关于睡眠的研究计划相结合。识别线虫由有害高温或组织损伤等条件引发的睡眠状态，表明细胞内稳态的扰动可能有助于睡眠驱动。线虫的应激诱导睡眠(SIS)可能代表了一种祖先状态，这种状态的进化是为了促进环境应激或感染后的恢复。在更复杂的生物体中，SIS可能与昼夜节律相协调，以抵消已知的与长时间清醒相关的动态平衡的扰动。这项提议的目的是描述促进SIS的遗传途径。主要研究人员已经证明，应激诱导的睡眠依赖于ALA神经内分泌细胞内表皮生长因子(EGF)受体的激活；然而，应激启动EGF信号转导的机制尚不清楚。这个项目的第一个目标是调查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，必须经过加工才能释放可溶性配体，因此EGF依赖的睡眠很可能受到应激诱导的胞外区域脱落的调节。该项目的第二个目标是确定哪个细胞(S)的表皮生长因子在应激反应中脱落，并表征已经在RNAi筛选中确定的睡眠缺陷的候选蛋白酶。该项目的第三个也是最后一个目标是通过无偏见的正向遗传筛查来识别SIS的新成分。

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.