REGULATORY MUTATIONS IN THE THREONINE OPERON

影响THR操纵子衰减的调节突变体 大肠杆菌将通过大肠杆菌肽定向 诱变和通过直接合成程序。 我们将 将移码突变引入前导肽编码中， 序列，以确定哪些区域对监管至关重要。 我们还将构建影响RNA的置换突变， 二级结构被认为是重要的， 调控 此外，我们还将研究DNA超螺旋 密度和终止因子对转录终止的影响 体外 这项工作的长期目标是了解 调节转录终止的分子事件 衰减器 第二个项目是关于 噬菌体λ位点特异性重组。 突变将 在体外引入结合位点， 蛋白质在重组期间结合。 突变将是 其特征在于它们对重组的影响， 与重组蛋白在DNA保护中的相互作用 测定。 我们还将构建新的DNA底物来研究 分支迁移和DNA-DNA相互作用的作用 重组 这项研究的长期目标是 了解链交换的分子机制， 获得关于组织和大会的信息 重组复合物

Regulatory mutants which affect attenuation of the thr operon of Escherichia coli will be constructed by oligonucleotide-directed mutagenesis and by direct synthesis procedures. We will introduce frameshift mutations into the leader peptide coding sequence to determine which region(s) are critical for regulation. We will also construct substitution mutations which affect RNA secondary structures that are thought to be important for regulation. In addition, we will study the effects DNA superhelix density and termination factors on transcription termination in vitro. The long range goal of this work is to understand the molecular events that regulate transcription termination at the thr attenuator. A second project is concerned with the molecular mechanism of bacteriophage lambda site-specific recombination. Mutations will be introduced in vitro into the binding sites where recombination proteins bind during recombination. The mutations will be characterized by their effects on recombination and by their interactions with recombination proteins in DNA protection assays. We will also construct novel DNA substrates to study the roles of branch migration and DNA-DNA interactions during recombination. The long range goal of this research is to understand the molecular mechanism of strand exchange and to gain information on the organization and assembly of recombination complexes.