Effects of the Atrial Natriuretic Factor enhancer and the 5'HS4 insulator on the probability of gene expression.

复杂的生物体包含许多不同类型的细胞，它们可以具有完全不同的外观和功能。所有这些细胞都含有相同的基因;它们之间的差异是通过选择性使用基因实现的。基因的选择性使用是理解复杂生物体如何发育的关键，也是理解这种发育在癌症、心脏病和其他常见疾病中是如何出错的关键。大量的证据表明，基因调控是通过蛋白质因子与基因侧翼DNA片段的相互作用完成的。我们工作的一个基本假设是，侧翼DNA元件的作用主要是增加基因活跃而不是沉默的概率。我们将询问，如果从小鼠心房利钠因子（ANF）基因中删除一个已知的调控元件，是否会降低心脏受压时心脏细胞表达ANF的可能性。这项实验也将为人类一种极其常见的疾病状态（心脏肥大）提供新的线索。在第二个实验中，我们将使用我们开发的一个新的实验系统来研究基因调控元件是否能够调节基因的表达量，以及是否能够打开基因。我们以前的工作表明情况并非如此，但我们希望进行更严格的测试。另一种假设是，没有DNA元件能够完全屏蔽转移基因与其周围的调控元件，因此，我们将测试一种DNA元件，该元件已被提议将任何基因与周围基因的所有影响隔离开，并询问它是否能够在基因组内的任何位点产生自主表达的基因。因为这些实验涉及的是所有基因共有的功能，所以这些实验将提供适用于操纵基因表达的广泛努力的信息。

Complex organisms contain many different types of cells, which can have completely different appearances and functions. All of these cells contain the same genes; the differences between them are achieved by the selective use of the genes. The means by which the selective use of genes is accomplished is a key to understanding how complex organisms develop, and how that development goes awry in cancer, heart disease, and other common disorders. A very large body of evidence indicates that gene regulation is accomplished by the interaction of protein factors with segments of DNA flanking the gene. One hypothesis underlying our work is that the flanking DNA elements act primarily to increase the probability that a gene will be active rather than silent. We will ask if removing a known regulatory element from the gene for Atrial Natriuretic Factor (ANF) in mice reduces the likelihood of ANF being expressed by heart cells when the heart is stressed. This experiment will also shed new light on an extremely common disease state in humans (cardiac hypertrophy). In a second experiment, we will use a new experimental system we have developed to ask if a gene regulatory element is able to dial up the amount of expression from a gene, as well as to switch the gene on. Our previous work suggested this was not the case, but we wish to conduct a more rigorous test. Another hypothesis is that no DNA element is able to completely shield a transferred gene from the regulatory elements surrounding it. Accordingly, we will test a DNA element that has been proposed to insulate any gene from all influences of surrounding genes, and ask if it is able to create an autonomously expressing gene at any site within the genome. Because they deal with functions that are common to all genes, these experiments will provide information that should be applicable to a broad array of efforts to manipulate gene expression.