GENE CONTROL IN INFECTION AND LYSOGENY BY PHAGE LAMBDA

我们的目标是了解大肠杆菌的RNA聚合酶是如何被修饰的 由噬菌体lambda基因Q编码的转录抗终止子。 抗终止是遗传调控的重要机制。 细菌以及真核生物--例如在艾滋病毒的生长过程中。 此外，许多细胞基因的表达可能受 在成绩单延长水平上起作用的相关过程。这个 所有RNA聚合酶的大亚基的广泛保守， 它们主要负责酶的运动和RNA链的生长， 表明在这些机制中将会有重要的共同特征 许多生物体中的伸长控制。大肠杆菌核糖核酸的相互作用 带有单个23kD Q多肽的聚合酶以及附件 NusA蛋白会改变酶的伸长特性，从而使其 通过转录终止子，不太容易受到某些 导致停顿的信号。Q在明确定义的位置修饰RNA聚合酶 包括晚期基因启动子的位置，DNA中的Q结合位置，以及 一种诱导转录暂停的DNA信号；这个信号起作用 主要通过与hon转录的链相互作用。这个 Q对暂停在此位置的酶的作用可能模拟Q函数在 终结符，因为它通过停顿来促进伸长。我们会 描述这种相互作用并确定其与活动的关系 Q蛋白的终止子，并描述终止的过程 它本身。我们将仔细分析Q蛋白，以确定与 DNA结合及其与RNA聚合酶的相互作用，使用两者 遗传和生化方法。我们将确定如何修改 由Q诱导的持续存在于启动子相关的参与位点 贯穿转录延伸的整个过程。

Our objective is to understand how RNA polymerase of E. coli is modified by the transcription antiterminator encoded by the phage lambda gene Q. Antitermination is an important mechanism of genetic regulation in bacteria, as well as eukaryotes - for example in the growth of HIV. Furthermore, expression of many cellular genes may be controlled by related processes that act at the level of transcript elongation. The extensive conservation of the large subunits of all RNA polymerases, which are mostly responsible for enzyme movement and RNA chain growth, suggests that there will be important common features in mechanisms of elongation control in many organisms. Interaction of E. coli RNA polymerase with the single 23 kD Q polypeptide, along with the accessory protein NusA, changes the elongation properties of the enzyme so that it goes through transcription terminators, and is less susceptible to some signals that induce pausing. Q modifies RNA polymerase at a well defined site that includes the late gene promoter, a Q binding site in DNA, and a DNA signal that induces transcriptional pausing; this signal acts primarily through interactions with the hon-transcribed strand. The action of Q on enzyme paused at this site may simulate Q function at terminators, because it promotes elongation through the pause. We will characterize this interaction and determine its relation to the activity of Q protein at terminators, and characterize the process of termination itself. We will dissect the Q protein to identify portions involved in DNA binding and in its interaction with RNA polymerase, using both genetic and biochemical methods. We will determine how the modification induced by Q persists from the promoter-associated engagement site throughout the process of transcription elongation.