DNA PRECURSOR DYNAMICS IN CELLS

DNA前体生物合成的酶是 抗癌、抗病毒和抗微生物药物，因为代谢 脱氧核糖核苷三磷酸的作用仅限于其 作为DNA前体的功能，抑制一种特定的合成 脱氧核糖核酸是一种选择性阻断DNA复制的方法 肿瘤细胞或感染细胞。有效利用核酸 化疗中的抗代谢药物需要了解 影响酶的细胞内组织和调控机制 DNTP的生物合成。这样的理解也可能导致洞察 DNA合成的控制--包括复制和修复。 该方案的具体目标包括：(1)确定机制 控制DNA前体池在细胞内的分布；(2) 定义有效DNA前体浓度和 DNA复制的速度和准确性；(3)定义细胞内 DNTP生物合成酶之间的相互关系；以及(4)评估 假设脱氧核糖核酸库是 烷基化试剂的诱变作用。 该项目使用培养的哺乳动物细胞和疫苗病毒作为生物 用于分析dNTP生物合成之间的细胞内关联的系统 酶和DNA前体池在细胞内的分布。子- 项目的重点是(1)病毒编码形式的结构和管理 核糖核苷酸还原酶，(2)脱氧核糖核酸库作为靶标 自发诱变和化学诱变；(3)细胞分析 DNTP代谢发生特异性改变的突变体，(4)测定 核内和核内核苷酸库隔离的基础 线粒体，以及(5)涉及的超分子组装分析 DNTP生物合成中的核苷酸还原酶等酶。

Enzymes of DNA precursor biosynthesis are targets for the actions of anticancer, antiviral, and antimicrobial drugs, because the metabolic roles of deoxyribonucleoside triphosphates dNTPs) are limited to their functions as DNA precursors, inhibition of the synthesis of a particular deoxyribonucleotide presents a selective way to block DNA replication in a neoplastic cell or an infected cell. Effective use of nucleic acid antimetabolites in chemotherapy requires understanding of the intracellular organization and regulatory mechanisms affecting the enzymes of dNTP biosynthesis. Such understanding may lead also to insight into the control of DNA synthesis--both replication and repair. Specific aims of this program include: (1) to define mechanisms controlling the intracellular distribution of DNA precursor pools; (2) to define relationships between effective DNA precursor concentrations and the rate and accuracy of DNA replication; (3) to define intracellular associations among enzymes of dNTP biosynthesis; and (4) to evaluate the hypothesis that deoxyribonucleotide pools are significant targets for the mutagenic effects of alkylating agents. This project uses cultured mammalian cells and vaccine virus as biological systems for analyzing intracellular associations among dNTP biosynthetic enzymes and the intracellular distribution of DNA precursor pools. Sub- projects focus upon (1) the structure and regulation of a virus-coded form of ribonucleotide reductase, (2) deoxyribonucleotide pools as targets for spontaneous and chemically induced mutagenesis, (3) analysis of cell mutants with specific alterations in dNTP metabolism, (4) determination of the basis for sequestration of nucleotide pools in nuclei and in mitochondria, and (5) analysis of supramolecular assemblies involving ribonucleotide reductase and other enzymes of dNTP biosynthesis.