Molecular Genetic Analysis of Plant Circadian Rhythms

在大约24小时内发生的节律性生物现象 在没有环境时间线索的情况下， 昼夜节律关于昼夜节律的两个基本问题 1）时间信息被用于： 调节观察到的有节奏的生物现象，以及2）时间 是经过测量的。为了解决前一个问题， 其表达在拟南芥中以昼夜节律的方式调节 thaliana.元素将被描述为所需的，在顺式 或反式，对于这种利用基因融合的昼夜节律调节，凝胶 DNA保护策略。时间的机制 将通过识别和 表征破坏生物计时的突变。 硝酸还原酶的昼夜节律将被探索， 如果蛋白质表达和mRNA水平相对应的话。如果他们 相应地，硝酸还原酶水平将被测量， 来筛选昼夜节律调节突变。融合基因， 将使用赋予报告基因的时钟控制 作为生物钟上的分子标记， 识别影响时钟功能的突变。昼夜 气孔开度的节律将用于选择突变体， 昼夜节律调节被改变。表征这些 突变将识别时钟本身的元素， 控制时间的调节系统。*** //

Rhythmic biological phenomena which occur at approximately 24 h intervals in the absence of environmental time cues are termed circadian rhythms. Two basic questions about circadian rhythms concern the mechanisms by which: 1) time information is used to regulate biological phenomena observed to be rhythmic, and 2) time is measured. To address the former, genes have been identified whose expression is regulated in a circadian fashion in Arabidopsis thaliana. Elements will be characterized that are required, in cis or in trans, for this circadian regulation using gene fusion, gel retardation and DNA protection strategies. The mechanism of time measurement will be addressed through the identification and characterization of mutations which disrupt biological timekeeping. The circadian rhythm in nitrate reductase will be explored to see if the protein expression and mRNA levels correspond. If they do correspond, nitrate reductase levels will be measured in an attempt to screen for circadian regulation mutations. Fusion genes, in which clock control is conferred on a reporter gene will be used as molecular tags on the biological clock in screens designed to identify mutations which affect clock function. The circadian rhythm in stomatal apertures will be used to select mutants in which circadian regulation is altered. Characterization of these mutations will identify elements either of the clock itself or of the regulatory system by which time control is exerted. *** //