Mechanisms of Genome Integrity

基因组完整性的机制

• 批准号: 9923696
• 负责人: Eric C Greene
• 金额: $ 51.06万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9923696
• 关键词: Address; BRCA2 gene; Cells; Chromosomal Rearrangement; Chromosomes; Complex; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; DNA Sequence; DNA biosynthesis; Defect; Embryo; Event; Genes; Genetic Predisposition to Disease; Genetic Recombination; Genome; Goals; Hereditary Malignant Neoplasm; Human; Individual; Lead; Link; Malignant Neoplasms; Malignant neoplasm of ovary; Microscopy; Monitor; Mus; Mutation; Natural regeneration; Optics; Outcome; Pathway interactions; Process; Proteins; Rad51 recombinase; Regulation; Research; Sequence Homologs; Single-Stranded DNA; Source; Technology; Time; ds-DNA; genetic information; genome integrity; homologous recombination; malignant breast neoplasm; prevent; programs; public health relevance; recruit; repaired; single molecule

 DESCRIPTION (provided by applicant): Our chromosomes are continually bombarded with a variety of insults, resulting in damage that must be repaired. By necessity, cells have evolved mechanisms to detect and repair broken strands of DNA, thereby preventing loss of important genetic information. Double-stranded DNA breaks (DSBs) are a type of damage that led to particularly disastrous outcomes. If not corrected, DSBs can lead to gross chromosomal rearrangements, which are the hallmark of all forms of cancer. Surprisingly, DNA replication is the primary source of DSBs. Homologous recombination (HR) is a highly conserved pathway that cells can use to repair DSBs, and HR is necessary to prevent and repair the damage that arises during DNA replication. When a DSB occurs, the DNA ends are processed to generate 3' single-strand DNA (ssDNA) overhangs. The ssDNA ends then pair with homologous sequence elsewhere in the genome, and the missing DNA sequence is replaced using the homologous DNA as a template for replication. Finally, the replicated intermediate is resolved, regenerating the continuity of the broken DNA. While seemingly simple, HR requires the coordinated action of a complex repertoire of proteins, which are responsible for sensing damage, recruiting essential factors, and processing and repairing the damaged DNA. The consequences of disrupting HR are devastating. For example, mutations in the Rad51 recombinase are embryonic lethal in mice, and mutations in human Rad51 are linked to breast cancers. In addition, defects in BRCA2 account for at least 5% of all breast cancers and also confer a genetic predisposition to ovarian cancer. BRCA2 is thought to help regulate HR, and loss of this regulation may be the reason why this gene is linked to hereditary cancers. Major new discoveries will be necessary to fully understand the mechanistic basis for these outcomes. Our overall research program is focused on understanding how (i) proteins sense and respond to damaged DNA, (ii) how DNA damage is repaired, (iii) how DNA replication can lead to damage, and (iv) how replication and recombination are linked. To help address these problems we have developed unique technologies that allow us to directly visualize hundreds of individual molecules using optical microscopy, which enables us to monitor the spatial and temporal progression of DNA repair and DNA replication in real-time at the single-molecule level. Using this approach we seek to define the fundamental mechanisms that our cells use to replicate and repair DNA, with the long-term goal of understanding how errors during these processes can lead to chromosomal rearrangements.

 描述（由申请人提供）：我们的染色体不断受到各种损伤的轰炸，导致必须修复的损伤。细胞必须进化出检测和修复断裂 DNA 链的机制，从而防止重要遗传信息的丢失。双链 DNA 断裂 (DSB) 是一种会导致特别灾难性后果的损伤，如果不加以纠正，DSB 可能会导致严重的染色体重排，这是所有形式的染色体重排的标志。令人惊讶的是，DNA 复制是 DSB 的主要来源。同源重组 (HR) 是细胞用来修复 DSB 的高度保守途径，并且 HR 对于预防和修复 DNA 复制过程中出现的损伤是必要的。发生这种情况时，DNA 末端会被加工生成 3' 单链 DNA (ssDNA) 突出端，然后 ssDNA 末端与基因组中其他位置的同源序列配对，并使用 ssDNA 序列替换缺失的 DNA 序列。最后，复制的中间体被解析，恢复断裂 DNA 的连续性，虽然看似简单，但 HR 需要复杂的蛋白质库的协调作用，这些蛋白质负责感知损伤、招募重要因子。 ，以及处理和修复受损的 DNA 的后果是毁灭性的，例如，Rad51 重组酶的突变对小鼠来说是致命的，而人类 Rad51 的突变与乳腺癌有关。 BRCA2 至少占所有乳腺癌的 5%，而且 BRCA2 被认为有助于调节 HR，而这种调节的丧失可能是该基因与遗传性癌症相关的原因。为了充分了解这些结果的机制基础，我们的整体研究计划的重点是了解（i）蛋白质如何感知和响应受损的 DNA，（ii）DNA 损伤如何修复，（iii）DNA 复制如何导致。到损伤，以及（iv）复制和重组如何联系起来，我们开发了独特的技术，使我们能够使用光学显微镜直接可视化数百个单个分子，从而使我们能够监测 DNA 修复的空间和时间进程。使用这种方法，我们试图定义细胞用于复制和修复 DNA 的基本机制，长期目标是了解这些过程中的错误如何导致。染色体重排。