Seasonal Adaptation of a Circadian Clock

描述（由申请人提供）：本提案的总体目标是了解昼夜节律起搏器如何适应新的相位调整，以响应环境温度和日照长度（光周期）的季节性变化。提出的具体目标的一个主要基础是基于我们先前的工作，表明来自D.黑腹期（per）RNA（命名为dmpi 8;黑腹果蝇Dper内含子8）充当传递日历信息的多模态“季节传感器”。DMPI 8在季节性寒冷天的高剪接效率（即，低温和短光周期）提前了“夜晚”活动的时间，赋予苍蝇在黄昏到来之前表现白天活动的能力。相反，dmpi 8在温暖的日子里的低剪接效率确保了苍蝇在正午炎热的阳光下最大限度地减少活动，并且主要是夜间活动，降低了与干燥相关的风险。我们还表明，norpA（无受体电位A）基因编码磷脂酶C（PLC β），调节温度和时钟控制dmpi 8剪接效率。这些发现确定了norpA的一种新的非光作用。在这个应用程序中，我们建议确定温度，光，时钟因素和NORPA如何共同调节dmpi 8的剪接效率，以及这种分子事件对节律行为中季节适应的贡献。主要目的是确定顺式作用元件介导的dmpi 8剪接的热敏性和调查的PLC/磷脂酰肌醇信号级联的作用。此外，我们还将分析从不同纬度分离的几种不同果蝇物种的自然种群中的时钟装置和行为节律。初步研究结果表明，每3 '-末端内含子是自然选择的目标，在适应季节性气候的地理变化的生物钟。为了实现这些目标，我们建议采取多方面的实验策略，包括生物化学，组织培养和整体动物的方法。我们的研究将增加对时钟功能季节适应的见解，并揭示norpA如何参与校准D。黑腹菌

DESCRIPTION (provided by applicant): The overall goal of this proposal is to understand how a circadian pacemaker accommodates new phase alignments in response to seasonal changes in ambient temperature and day length (photoperiod). A major foundation for the proposed specific aims is based on our prior work showing that the thermosensitive and photosensitive splicing of the 3'-terminal intron from the D. melanogaster period (per) RNA (termed dmpi8; D. melanogaster dper intron 8) acts as a multi-modal "seasonal sensor" conveying calendar information. High splicing efficiency of dmpi8 on seasonally cold days (i.e., low temperatures and short photoperiods) advances the timing of 'evening' activity, endowing flies with the ability to manifest daytime activity despite the early onset of dusk. Conversely, low splicing efficiency of dmpi8 on warm days ensures that flies minimize activity during the hot midday sun and are mainly nocturnal, lowering the risks associated with desiccation. We also showed that the norpA (no receptor potential A) gene encoding phospholipase C (PLCbeta), modulates the temperature and clock control of dmpi8 splicing efficiency. These findings identified a novel non-photic role for norpA. In this application we propose to determine how temperature, light, clock factors and NORPA co-regulate the splicing efficiency of dmpi8, and the contribution of this molecular event to seasonal adaptation in rhythmic behavior. Major objectives are to identify cis-acting elements that mediate thermosensitivity of dmpi8 splicing and investigate the role of the PLC/phosphatidylinositol signaling cascade. Moreover, we will analyze the clockworks and behavioral rhythms in natural populations of several different Drosophila species isolated from a wide range of latitudes. Preliminary findings suggest that per 3'-terminal introns are targets for natural selection in the adaptation of circadian clocks to geographical variations in seasonal climates. To accomplish these goals we propose to take multifacted experimental strategies including biochemical, tissue culture and whole animal approaches. Our studies will add insights into seasonal adaptation of clock function and reveal how norpA participates in calibrating molecular and behavioral thermoresponses in D. melanogaster.