DNA MODIFICATION IN CARCINOGENESIS AND MUTATION

致癌和突变中的 DNA 修饰

• 批准号: 2101354
• 负责人: TIMOTHY H BESTOR
• 金额: $ 17.39万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-15 至 1997-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2101354
• 关键词: 5 fluorodeoxycytidine; 5 methylcytosine; DNA methylation; amination; aminohydrolases; carcinogenesis; chimeric proteins; cytosine; embryonic stem cell; enzyme activity; enzyme inhibitors; gene deletion mutation; gene mutation; laboratory mouse; methyltransferase; neoplasm /cancer genetics; nucleic acid probes; nucleic acid sequence; oligonucleotides; polymerase chain reaction; protein purification; protein structure function; teratoma; tissue /cell culture; transfection

Current evidence suggest that errors in the establishment of maintenance of genomic methylation patterns contribute to ectopic gene inactivation of reactivation. These errors are likely to be involved in certain human diseases; this is especially true to tumors, whose growth depends on the inactivation of humor suppressor genes. In cultured cells, ectopic methylation and actual mutations are each responsible for approximately half of all cases of gene inactivation, and we make the specific prediction that some portion of human tumors will show inactivation of tumor suppressor genes by ectopic methylation. Also, there exists very intriguing evidence for enzyme-mediated conversion of m5C to T and C to U; these mutations commonly contribute to carcinogenesis and genetic disease. Biochemical and genetic means will be used to test for DNA cytosine deaminases and for DNA 5-methylcytosine deaminases in lysates of mammalian cells. The chemistry of the transmethylation reaction suggests that DNA Methyltransferase should act as a DNA cytosine deaminase in the absence of S-adenosyl L-methionine, and this prediction will also be tested. Sequence-specific methylation patterns are established during gametogenesis and early development. Errors in sequence-specific methylation can be expected to cause developmental defects, and Fragile X syndrome and perhaps Huntington's disease involve defective DNA methylation. Since nothing is known of the regulation of sequence- specific de novo methylation, experiments are proposed that will determine whether sequence-specific de novo methyltransferases are present at developmental stages where methylation patterns are undergoing rapid changes. These experiments will use a very sensitive and specific universal probe for DNA (cytosine-5)-methyltransferases based on the suicide substrate 5-fluoro 2'-deoxycytidine. The specificity and other functions of the known form of DNA Nethyltransferase will be studied in existing mutant cell lines which allow the selection of active mutants of DNA Nethyltransferase. This proposal describes experimental approaches to the role of DNA modification in carcinogenesis and genetic disease.

目前的证据表明，维护建立中的错误 基因组甲基化模式导致异位基因失活 的重新激活。这些错误可能与某些人为因素有关 疾病；对于肿瘤来说尤其如此，其生长取决于 体液抑制基因失活。在培养细胞中，异位 甲基化和实际突变分别负责大约 一半的基因失活病例，我们做出了具体的 预测人类肿瘤的某些部分将表现出失活 抑癌基因通过异位甲基化。另外，还存在着非常 酶介导的 m5C 转化为 T 和 C 转化为 T 的有趣证据 你；这些突变通常会导致癌症发生和遗传 疾病。生化和遗传学手段将用于检测DNA 裂解物中的胞嘧啶脱氨酶和 DNA 5-甲基胞嘧啶脱氨酶 哺乳动物细胞。甲基转移反应的化学原理 表明 DNA 甲基转移酶应充当 DNA 胞嘧啶 在没有 S-腺苷 L-甲硫氨酸的情况下脱氨酶，这个预测 也将受到考验。 序列特异性甲基化模式是在 配子发生和早期发育。序列特异性错误 甲基化预计会导致发育缺陷，并且脆弱 X 综合征和亨廷顿病可能与 DNA 缺陷有关 甲基化。由于对序列的调节一无所知—— 特定的从头甲基化，建议进行实验 确定序列特异性从头甲基转移酶是否 存在于甲基化模式的发育阶段 正在经历快速的变化。 这些实验将使用非常敏感的 和 DNA (胞嘧啶-5)-甲基转移酶的特异性通用探针 基于硅化物底物 5-氟 2'-脱氧胞苷。这 已知 DNA 形式的特异性和其他功能 将在现有的突变细胞系中研究甲基转移酶 允许选择 DNA 甲基转移酶的活性突变体。这 提案描述了研究 DNA 作用的实验方法 致癌作用和遗传病的改变。