DNA REPLICATION AND GENOME STABILITY

DNA 复制和基因组稳定性

• 批准号: 8559627
• 负责人: Lyle Simmons
• 金额: $ 28.25万
• 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/8559627
• 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 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）：这项研究的长期目标是了解负责从染色体DNA插入和去除核糖核苷（RNMP）的机制。遗传物质的准确重复对于所有活细胞都是必不可少的。最近，很明显，DNA聚合酶直接将核糖糖作为RNMPS掺入DNA中。 DNA的标志是它在化学上是稳定的，而反应性比RNA的反应性要小得多。核糖糖上的2'羟基导致RNMP的反应性更高，导致水解和DNA在正常生理条件下断裂。此外，在复制过程中，RNTP的细胞内浓度远远超过了其对染色体DNA的误解的DNTP。 RNMP掺入的错误率表明，不正确的估计发生了一个〜103个正确配对的碱基，从而使RNMP误差远远超过了任何类型的复制误差或体内损坏的碱的误差。我们发现细菌中的复制性DNA聚合酶经常掺入DNA中。在这项工作中，我们将阐明RNMP未经修复时插入，去除和基因组完整性的后果的机制。此外，我们发现了一种新型蛋白质，将RNMP去除与基因组完整性联系起来，从而为RNMP误差提供了进化益处。合并的RNMP对人类健康有深远的影响。核糖核苷单磷酸盐缓慢的DNA合成和RNMP具有诱变潜力。此外，RNase H2负责从DNA中去除单个RNMP的酶在小鼠中至关重要，并且人RNase H2的突变导致神经系统疾病称为AICARDI-GOTIERES综合征。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。我们的具体目的是：1）确定体外RNMP掺入的速率； 2）确定RNMP去除的机制； 3）确定RNMP去除对基因组完整性的进化益处。