DNA REPLICATION AND GENOME STABILITY

DNA 复制和基因组稳定性

• 批准号: 9113041
• 负责人: Lyle Simmons
• 金额: $ 28万
• 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/9113041
• 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; System; Testing; Work; base; deoxyribonucleoside triphosphate; genome integrity; in vitro activity; in vivo; link protein; nervous system disorder; novel; pseudotoxoplasmosis syndrome; 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从染色体DNA中插入和移除核糖核苷单磷酸（rNMPs）的机制。遗传物质的精确复制对所有活细胞都是必不可少的。近年来，DNA聚合酶直接将核糖糖作为核糖核酸聚合酶（rnmp）整合到DNA中。DNA的一个特点是它的化学性质稳定，比RNA的反应性低得多。在正常的生理条件下，核糖糖上的2'羟基导致rNMPs的活性增加10万倍，导致水解和DNA断裂。此外，rNTPs的细胞内浓度远远超过dNTPs，导致它们在复制过程中误插入染色体DNA。rNMP结合的错误率表明，每~103个正确配对的碱基就会发生错误结合，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。我们发现细菌的复制性DNA聚合酶经常将rNMPs合并到DNA中。在这项工作中，我们将阐明插入、移除的机制，以及当rnmp未被修复时对基因组完整性的影响。此外，我们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。合并的rnmp对人类健康具有深远的影响。核糖核苷单磷酸缓慢DNA合成和核糖核酸mps具有诱变潜力。此外，RNase H2（负责从DNA中去除单个rNMPs的酶）在小鼠中是必不可少的，而人类RNase H2的突变会导致被称为aicardii - 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在体外的掺入率；2)确定rNMP去除的机制；3)确定去除rNMP对基因组完整性的进化益处。