通过光线和昼夜时钟调节Jun-B信使RNA和AP-1活动
J M Kornhauser1, D E Nelson, K E Mayo
1Institute for Neuroscience, Northwestern University, Evanston, IL 60208.
概括
光同步哺乳动物的昼夜时钟在上神核 (SCN). 这个过程涉及到像jun-B这样的直接早期基因,对于昼夜活动至关重要.
科学领域:
- 神经科学是一个神经科学.
- 时间生物学 时间生物学
- 分子生物学分子生物学
背景情况:
- 下丘脑中的上神核 (SCN) 在哺乳动物中充当主昼夜节律起器.
- 昼夜节律是由外部线索,主要是光线,同步 (引诱) 的.
- 直接早期的基因,如c-fos,在对光等刺激的反应中迅速表达,这表明它在神经可塑性和信号传递中发挥了作用.
研究的目的:
- 为了研究在昼夜照射过程中SCN中即时早期基因表达的作用.
- 为了确定SCN中的光诱导基因表达是否依赖相位,并与行为节律变化有关.
主要方法:
- 在暴露于光线后,测量动物和黄金仓鼠的SCN中c-fos,c-jun和jun-B的信使RNA (mRNA) 水平.
- 评估SCN中AP-1转录因子复合物的结合活性.
- 关联基因表达和AP-1结合活性与昼夜阶段以及行为节律变化的发生.
主要成果:
- 光刺激会诱导SCN中的c-fos基因表达,使得Fos参与到昼夜活动中.
- 性刺激特别提高了SCN中的Jun-B mRNA和AP-1DNA结合活性,对c-jun的影响最小.
- jun-B mRNA和AP-1结合的诱导是相位依赖的,只有当光刺激改变行为节奏时才会发生.
结论:
- 光和SCN昼夜节律起器相互作用,调节特定的直接早期基因.
- 在SCN中Jun-B和AP-1活动的光学调节是潜在参与昼夜节律的关键机制.
- 这些发现突出了通过SCN处理光信息以调整内部生物钟的分子通路.
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