GENE CONTROL IN INFECTION AND LYSOGENY BY PHAGE LAMBDA

我们将研究E. 大肠杆菌，它们是所有细胞中遗传调控的模型。 1.由噬菌体λ基因Q编码的蛋白质激活噬菌体晚期 通过在特定操纵子中起转录作用的基因表达 抗终止剂 抗终止是一种重要的调节机制， 细菌，可能还有所有的细胞和病毒。 我们将决定如何 λ Q蛋白在基因组特异性位点被RNA聚合酶接合 在启动子附近，使用化学和核酸酶保护方法来探测 它与DNA的相互作用，利用突变，我们将使这种改变 以特定的方式互动。 我们将确定Q蛋白如何修饰 RNA聚合酶的特性使其能够通过转录终止子， 以及它是如何改变RNA聚合酶在特征性的 网站. 我们将研究转录因子NusA的作用， 抗终止蛋白。 2.除了在基因重组中催化DNA链交换外， 急诊coli RecA蛋白介导SOS基因的诱导，其中包括 最重要的突变所需的DNA修复功能 致癌物质。 致癌物也是SOS基因（和噬菌体）的诱导物。 λ），因为它们导致RecA蛋白的活化以结合， 通过蛋白水解裂解破坏SOS基因的莱克萨阻遏物，如 以及温和的噬菌体阻遏物。 为了测试这个模型， 当染色体复制发现DNA中的缺口时， 致癌物诱导的病变，我们将确定莱克萨之间的关系 切割和DNA复制。 为了检验这一规定的普遍性， 我们将研究RecA蛋白的类似物， 细菌B。枯草杆菌。

We will investigate two fundamental processes of genetic control in E. coli, which are models for genetic regulation in all cells. 1. The protein encoded by bacteriophage lambda gene Q invokes phage late gene expression by acting in a specific operon as a transcription antiterminator. Antitermination is an important mechanism of regulation in bacteria, and possibly in all cells and viruses. We will determine how lambda Q protein is engaged by RNA polymerase at a genome-specific site near the promoter, using chemical and nuclease protection methods to probe its interaction with DNA, and using mutations we will make that change this interaction in specific ways. We will determine how Q protein modifies the properties of RNA polymerase to allow it to pass transcription terminators, and how it changes the ability of RNA polymerase to pause at characteristic sites. We will investigate the role of the transcription factor NusA protein in antitermination. 2. In addition to catalyzing DNA strand exchange in genetic recombination, the E. coli RecA protein mediates induction of the SOS genes, which include DNA repair functions required for mutagenesis by most important carcinogens. Carcinogens are also inducers of SOS genes (and phage lambda), because they lead to activation of RecA protein to bind and destroy by proteolytic cleavage the LexA repressor of the SOS genes, as well as temperate phage repressors. To test the model that induction occurs when chromosome replication uncovers gaps in DNA at the sites of carcinogen-induced lesions, we will determine the relation between LexA cleavage and DNA replication. To test the universality of this regulation, we will study an analogue of RecA protein in the distantly related bacterium B. subtilis.