MOLECULAR BIOLOGY OF THE MAMMALIAN CIRCADIAN CLOCK

哺乳动物昼夜节律的分子生物学

• 批准号: 2252026
• 负责人: CHARLES J WEITZ
• 金额: $ 8.52万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2252026
• 关键词: DNA binding protein; RNase protection assay; animal genetic material tag; chimeric proteins; circadian rhythms; complementary DNA; gene expression; genetic library; in situ hybridization; molecular cloning; molecular psychobiology; northern blottings; nucleic acid sequence; photostimulus; reporter genes; suprachiasmatic nucleus; transcription factor

Circadian rhythms are daily rhythms in behavior, metabolism, or other biological activities that persist even in the presence of constant environmental conditions. The oscillators that drive the overt biological rhythms found in virtually all eukaryotes presumably evolved as a result of selection for an internal timekeeping system that would allow anticipation of predictable daily environmental cycles. Abnormalities of circadian processes have been widely observed in patients with major affective disorders. These abnormalities can take the form of a reduction in amplitude of circadian rhythms or of an inappropriate phase relationship of different circadian rhythms to one another. These long-standing observations raise the possibility that circadian abnormalities may be directly related to the pathophysiology or symptomatic expression of major affective disorders. The intriguing connection between major affective disorders and circadian dysfunction cannot be examined in detail until much more is known about the molecular mechanism of the circadian clock in mammals, which at present is entirely obscure. The objective of this research program is to initiate the identification of candidate circadian clock molecules expressed in the mammalian suprachiasmatic nucleus (SCN), the known location of the circadian oscillator. Recently-developed methods for protein-protein interaction cloning allow the isolation of any mammalian clock component that has retained the ability to interact with the Period protein, a circadian clock component from Drosophila that shares with certain mammalian transcription factors a dimerization interface known as the PAS domain. In any complex regulatory loop such as the circadian pacemaker is likely to be, it is probable that the various components interact with a number of positive and negative regulatory factors and effectors---perhaps the best example at present is the regulation of the cell cycle, with its cyclins, cyclin-dependent kinases, phosphatases, kinase inhibitors, and targeted proteolysis. Thus the general goal is to identify any proteins expressed in the SCN that are capable of specifically interacting with various fragments of Per, including (but not limited to) novel PAS dimerization partners. Such proteins could very well represent distant mammalian relatives of circadian regulatory factors in Drosophila. We will use the two-hybrid genetic system to isolate SCN cDNAs encoding proteins that can interact with Period or other PAS proteins. Knowledge of the molecular mechanism of circadian pacemaking in the SCN will provide biochemical and genetic markers for a detailed analysis of the relationship between abnormalities of the circadian system and affective disorders.

昼夜节律是行为、代谢或其他生理过程中的每日节律。 生物活动，即使在存在恒定的 环境条件 驱动显性信号的振荡器 几乎所有的真核生物都有生物节律， 由于选择了内部计时系统， 允许预测可预测的日常环境周期。 昼夜节律过程的异常在人类中被广泛观察到， 患有严重情感障碍的患者。 这些异常现象 昼夜节律幅度的降低或 不同昼夜节律的不适当相位关系 另 这些长期的观察提出了一种可能性， 昼夜节律异常可能与病理生理学直接相关 或严重情感障碍的症状表现。 主要情感障碍和昼夜节律之间的有趣联系 功能障碍不能详细检查，直到更多的是了解 哺乳动物生物钟的分子机制， 现在是完全模糊的。 这项研究计划的目标是 开始鉴定候选生物钟分子 在哺乳动物视交叉上核（SCN）中表达，已知的 昼夜节律振荡器的位置。最近开发的方法， 蛋白质-蛋白质相互作用克隆允许分离任何哺乳动物 时钟组件，保留了与周期交互的能力 蛋白质，一种来自果蝇的生物钟成分， 某些哺乳动物转录因子已知的二聚化界面 作为PAS域。 在任何复杂的调节回路中， 起搏器很可能是，很可能是各种组件， 与一些积极和消极的调节因素相互作用， 目前最好的例子也许是对 细胞周期，与其周期蛋白，周期蛋白依赖性激酶，磷酸酶， 激酶抑制剂和靶向蛋白水解。 因此，总的目标是 以鉴定SCN中表达的任何能够 特别是与Per的各种片段相互作用，包括（但 不限于）新的PAS二聚化配偶体。 这些蛋白质可以 很好地代表了昼夜节律调节的哺乳动物远亲 果蝇的因素 我们将使用双杂交遗传系统， 分离的SCN cDNA编码可与Period或 其他PAS蛋白 SCN中昼夜节律起搏的分子机制的知识 将提供生物化学和遗传标记， 昼夜节律系统异常与 情感障碍