DNA REPLICATION AND GENOME STABILITY

DNA 复制和基因组稳定性

• 批准号: 8705549
• 负责人: Lyle Simmons
• 金额: $ 28.17万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8705549
• 关键词: Address; Affect; Bacillus subtilis; Bacteria; Bacterial Genome; Base Pairing; Biochemical; Biological; Biological Models; Biological Process; Cells; DNA; DNA biosynthesis; DNA-Directed DNA Polymerase; Defect; Development; Educational process of instructing; Embryo; Enzymes; Escherichia coli; Eukaryota; Excision; Frequencies; Genetic; Genetic Materials; Genome; Genome Stability; Genomic DNA; Genomic Instability; Genomics; H2 gene; Health; Hereditary Disease; Human; Hydrolysis; Hydroxyl Radical; In Vitro; Investigation; Left; Life; Link; Location; Malignant Neoplasms; Measures; Methylation; Mismatch Repair; Mus; Mutagenesis; Mutation; Pathway interactions; Physiological; Process; Prokaryotic Cells; Proteins; RNA; Replication Error; Research; Ribonucleases; Ribonucleosides; Ribose; Signal Transduction; Syndrome; System; Testing; Work; base; deoxyribonucleoside triphosphate; in vitro activity; in vivo; link protein; nervous system disorder; novel; public health relevance; repaired; sugar; tool; tripolyphosphate

DESCRIPTION (provided by applicant): The long-term objective of this research is to understand the mechanisms responsible for insertion and removal of ribonucleoside monophosphates (rNMPs) from chromosomal DNA. The accurate duplication of genetic material is essential for all living cells. Recently, it has become apparent that DNA polymerases directly incorporate ribose sugars into DNA as rNMPs. A hallmark of DNA is that it is chemically stable and much less reactive than RNA. The 2' hydroxyl on the ribose sugar causes rNMPs to be 100,000 fold more reactive resulting in hydrolysis and DNA breaks under normal physiological conditions. Furthermore, the intracellular concentration of rNTPs far exceeds that of dNTPs contributing to their misinsertion into chromosomal DNA during replication. Error rates for rNMP incorporation suggest misincorporation occurs every ~103 correctly paired bases making rNMP errors far exceed that of any type of replication error or damaged base in vivo. We have found that the replicative DNA polymerases in bacteria frequently incorporation rNMPs into DNA. In this work, we will elucidate the mechanisms of insertion, removal, and the consequences to genome integrity when rNMPs are left unrepaired. Moreover, we have found a novel protein that links rNMP removal to genome integrity providing an evolutionary benefit for rNMP errors. Incorporated rNMPs have profound effects on human health. Ribonucleoside monophosphates slow DNA synthesis and rNMPs have mutagenic potential. Furthermore, RNase H2 the enzyme responsible for removing single rNMPs from DNA is essential in mice and mutations in human RNase H2 results in a neurological disorder known as Aicardi-Goutieres syndrome. Thus, our studies of rNMP insertion and removal have practical implication for human health. Our specific aims are: 1) to determine the rate of rNMP incorporation in vitro; 2) determine the mechanisms of rNMP removal; 3) determine the evolutionary benefit of rNMP removal to genome integrity.

描述（由申请人提供）：本研究的长期目标是了解核糖核苷单磷酸 (rNMP) 从染色体 DNA 中插入和去除的机制。遗传物质的精确复制对于所有活细胞都至关重要。最近，人们发现 DNA 聚合酶可以将核糖作为 rNMP 直接掺入 DNA。 DNA 的一个特点是它的化学性质稳定且反应性比 RNA 低得多。核糖上的 2' 羟基使 rNMP 的反应性提高 100,000 倍，导致正常生理条件下的水解和 DNA 断裂。此外，rNTP 的细胞内浓度远远超过 dNTP，导致它们在复制过程中错误插入染色体 DNA。 rNMP 掺入的错误率表明每约 103 个正确配对的碱基就会发生错误掺入，这使得 rNMP 错误远远超过体内任何类型的复制错误或受损碱基的错误。我们发现细菌中的复制DNA聚合酶经常将rNMPs掺入DNA中。在这项工作中，我们将阐明插入、去除的机制，以及 rNMP 未修复时对基因组完整性的影响。此外，我们还发现了一种新的蛋白质，它将 rNMP 去除与基因组完整性联系起来，为 rNMP 错误提供了进化益处。掺入的 rNMP 对人类健康具有深远的影响。单磷酸核糖核苷会减缓 DNA 合成，而 rNMP 具有致突变潜力。此外，RNase H2（负责从 DNA 中去除单个 rNMP 的酶）对于小鼠来说是必需的，而人类 RNase H2 的突变会导致一种称为 Aicardi-Goutieres 综合征的神经系统疾病。因此，我们对 rNMP 插入和去除的研究对人类健康具有实际意义。我们的具体目标是：1）确定rNMP的体外掺入率； 2）确定rNMP去除机制； 3) 确定去除 rNMP 对基因组完整性的进化益处。