FACTORS INFLUENCING GENETIC TRANSCRIPTION-INITIATION AND TERMINATION

RNA在细胞调节中发挥着重要作用--无论是通过它的 以活跃的形式存在或完全不存在。它因 DNA转录并不一定会导致 多产、成熟的RNA分子。这些RNA分子的裂解通常是 RNA分子成熟所必需的，或作为 其他过程(例如，启动DNA复制)。这些卵裂事件 是被称为RNA加工的一般成熟途径的子集。工作 与两种类型的RNA有关 用于DNA复制和核糖体RNA的RNA引物的加工、生成 在高等真核生物中的加工。我们研究了它们之间的关系 核糖核酸酶H(RNase H)的氨基酸序列和酶活性 核糖核酸酶H活性改变的大肠杆菌突变株的检测 鼠伤寒沙门氏菌核糖核酸酶氨基酸序列的测定 H和酵母RNase H。酵母RNase H的编码基因已被 位于XIII染色体右臂的酵母遗传图谱上，约 从端粒上移出250千碱基。酵母核糖核酸酶H基因的失活 产生表现出正常生长表型的菌株。处理的过程中 对突变的BHK细胞中的核糖体RNA也进行了研究。这个 温度敏感的表型已通过转导 用小鼠cdna文库突变细胞。

RNA plays an important role in cellular regulation -- either by its presence in active form or by its total absence. It ha been known for several years that transcription of DNA does not necessarily lead to productive, mature RNA molecules. Cleavage of these RNA molecules often is required for the RNA molecules to mature or to act as an intermediate in other processes (e.g., priming of DNA replication). These cleavage events are a subset of a general maturation pathway known as RNA processing. Work of this Intramural Research Project is concerned with two types of RNA processing, generation of RNA primers for DNA replication and ribosomal RNA processing in higher eukaryotes. We have studied the relationship between amino acid sequence and enzymatic activity of ribonuclease H (RNase H) by examination of mutants of Escherichia coli with altered RNase H activities, by determination of the amino acid sequence of Salmonella typhimurium RNase H and a yeast RNase H. The gene coding for the yeast RNase H has been located on the yeast genetic map to the right arm of chromosome XIII about 250 kilobase from the telomere. Inactivation of the yeast RNase H gene produces strains that exhibit normal growth phenotypes. The processing of ribosomal RNa in the mutant BHK cell line has also been studied. The temperature sensitive phenotype has been corrected by transfection of the mutanmt cells with a cDNA library from mouse.