ISOLATION AND CHARACTERIZATION OF ACANTHAMOEBA GENES

稳定RNA的转录和表达调控机制 (前体核糖体和5S)正在研究中。规管的证据 辅助转录蛋白调控稳定的RNA合成 水平，通过RNA聚合酶修饰和反式作用蛋白 是在这个实验室和其他实验室获得的。作为研究的第一步， 5S RNA转录调控机制及5S RNA的克隆 基因的全基因组结构和一级序列的测定 是提议的。5S RNA无细胞转录系统的建立 补充本实验中已经使用的rRNA转录系统 建议。将利用5S RNA转录系统来检测 发育调节的5S RNA关闭的分子机制 表情。重点将放在研究两者之间的关系上 5S和核糖体RNA平行关闭的机制 停止细胞的生长和增殖。 对rRNA启动子结构的研究正在进行中。删除 在体外构建和测试转录活性的突变 确定了rRNA转录起始附近的一个50碱基对区域 站点作为启动子。这项提案旨在提出一系列观点 该序列中的突变，以便更准确地定义 启动子和辅助转录蛋白之间的相互作用。

Mechanisms of transcription and regulation of expression of stable RNAs (precursor ribosomal and 5S) are being studied. Evidence for regulation of stable RNA synthesis by modulation of auxilliary transcriptional protein levels, by RNA polymerase modification and by trans-acting proteins has been obtained in this lab and others. As an initial step in studying the mechanism of regulation of 5S RNA transcription, cloning of the 5S RNA gene, determination of its overall genomic structure and primary sequence is proposed. Development of a cell-free transcription system for 5S RNA to complement the rRNA transcription system already in use in this lab is also proposed. The 5S RNA transcription system will be utilized to examine the molecular mechanism of developmentally regulated shutoff of 5S RNA expression. Emphasis will be on studying the relationship between the mechanisms of the parallel shutdown of 5S and ribosomal RNA resulting from cessation of cellular growth and proliferation. Studies of the structure of the rRNA promoter are ongoing. Deletion mutations constructed and tested for transcriptional activity in vitro have identified a 50 base pair region proximal to the rRNA transcription start site as the promoter. This proposal aims to produce a series of point mutations within this sequence in order to more precisely define the interactions between the promoter and auxilliary transcriptional proteins.