DISSERTATION RESEARCH: Evolutionary Physiology of Heat-Shock Gene Expression

论文研究：热休克基因表达的进化生理学。马丁·E·费德和丹尼尔·勒曼拟议中的研究将调查一个引人注目的案例，在这个案例中，转座元件[TES，基因组中能够从一个地方移动到另一个地方的DNA片段]反复但独立地干扰了编码可诱导分子伴侣[一种防止或减轻对其他蛋白质的损害的蛋白质；例如，Hsp70]的基因的启动子[控制转录的区域]，这反过来又应该影响对环境压力的耐受和适应性。这一系统很有希望成为研究种群内个体间微小差异如何引起生理特性的大范围差异的模型。先前的研究已经发现了3个独立的例子，在果蝇的自然种群中，TE插入破坏了hsp70BA近端启动子中热休克反应元件之间的间隔；每个这样的种群都表现出独特的Hsp70蛋白水平。对于每个种群，拟议的研究将建立复制系，用于：(1)量化Hsp70蛋白水平，以测试带有TE干扰启动子的果蝇是否表达较少的Hsp70；(2)确定TE驱动的Hsp70表达的差异是否影响诱导热耐受，这是Hsp70在生物体水平的一种主要表型；(3)通过特异的核糖核酸酶保护分析，确定TES是否破坏HSP70的反式激活[Hsp70编码基因的转录]；(4)测量是否如预测的那样，hsp70ba启动子的TE干扰增强了没有经历热应激的果蝇的适应性。这项拟议的研究将整合分子遗传学、生化和生理学方法，并将是最早阐明种群内调控序列变异和表型多样性之间联系的研究之一。

Dissertation Research: Evolutionary Physiology of Heat-Shock Gene ExperessionDr. Martin E. Feder & Daniel LermanThe proposed research will investigate a remarkable case in which transposable elements [TEs, pieces of DNA that have the ability to move from one place to another within the genome] have repeatedly but independently disrupted the promoter [region controlling transcription] of a gene encoding an inducible molecular chaperone [a protein that prevents or alleviates damage to other proteins; e.g., Hsp70], which in turn should affect tolerance of environmental stress and fitness. This system has great promise as a model for investigating how large-scale differences in physiological traits arise from minor variation among individuals within populations. Prior research has discovered 3 independent instances in which, in natural populations of the fruit fly Drosophila, TE insertions disrupt the spacing between heat-shock response elements in the hsp70Ba proximal promoter; each such population exhibits distinctive Hsp70 protein levels. For each population, the proposed research will develop replicate lines with which to: (1) Quantify Hsp70 protein levels to test whether flies with TE-disrupted promoters express less Hsp70; (2) Determine whether TE-driven differences in Hsp70 expression affect inducible thermotolerance, a principle organism-level phenotype of Hsp70; (3) Determine, via specific ribonuclease protection assays, whether the TEs disrupt hsp70 transactivation [transcription of the Hsp70-encoding gene]; (4) Measure whether, as predicted, TE-disruption of the hsp70Ba promoter enhances fitness in Drosophila not undergoing heat stress. The proposed research will integrate molecular genetic, biochemical and physiological approaches, and be among the first to elucidate the link between intrapopulation regulatory sequence variation and phenotypic diversification.