Chromosomal consequences of DNA precursor pools imbalances and contamination

在此输入文本，它是您的应用程序的新摘要信息。这 部分不得超过30行文本。 这项研究的主要目标是研究细胞的染色体后果 无法维持DNA前体池的三个关键方面：它们的数量， 他们的平衡和纯洁。DNA前体池的质量早已得到认可 因为它在避免突变方面发挥了重要作用，这对生物的进化具有重要意义 任何物种。最近，我们一直主张有限的、 不平衡或受污染的DNA前体池，这是染色体的形成 威胁细胞生存的损伤，需要复杂的DNA修复系统，称为 “重组修复”。我们已经提出了两个基本类比的通用模型 整合到DNA中可能导致染色体碎裂，这需要 重组修复。在我们之前的工作中，我们确定尿嘧啶和次黄嘌呤是 主要的碱基类似物污染了大肠杆菌中的DNA前体池。同时， 污染DNA前体的其他天然碱基类似物的鉴定和来源 池子仍然未知。而且，即使一开始DNA前体池不平衡 会导致可修复的染色体损伤，最终会产生不可修复的 未知性质的染色体损伤。我们最近的观察为我们提供了对 可能导致无法修复的染色体损伤的情况以及导致 这些损伤，虽然基因组分析的引入提供了一个机会来识别 染色体中受影响最严重的部分。这项研究的目标1涉及具体的 次黄嘌呤、尿嘧啶或丙二醛诱发染色体断裂的机制 氟尿嘧啶。目标2侧重于描述神秘来源的DNA 在胸腺嘧啶饥饿期间消失，与无胸腺嘧啶的死亡同时发生。AIM 3测试 我们最近提出的无胸腺素性死亡的多阶段模型，开始于 现有复制分叉的停滞，通过未知数量的 中间阶段，以复制起点的破坏结束。总而言之，这 工作将强调保持DNA前体池充足、平衡和 通过确定泳池不平衡和污染的各种来源进行消毒， 以及染色体上的后果，包括不可修复的损伤，由 池塘污染和失衡。

Enter the text here that is the new abstract information for your application. This section must be no longer than 30 lines of text. The broad goal of this study is to investigate the chromosomal consequences of cell's inability to maintain the three critical aspects of the DNA precursors pools: their quantity, their balance and their purity. Quality of DNA precursor pools has been long recognized for its important role in avoidance of mutagenesis, which is significant for evolution of any species. Recently, we have argued for a more immediate consequence of limited, imbalanced or contaminated DNA precursor pools, which is formation of chromosomal lesions that threaten cell's survival and that require complex DNA mending system called "recombinational repair". We have proposed two general models of how base analog incorporation into DNA could lead to chromosomal fragmentation that requires recombinational repair. In our previous work, we identified uracil and hypoxanthine as the major base analogs contaminating DNA precursor pools in E. coli. At the same time, the identity and the sources of other natural base analogs contaminating DNA precursor pools remain unknown. Moreover, even though DNA precursor pool imbalance at first leads to reparable chromosomal lesions, it eventually generates irreparable chromosomal lesions of unknown nature. Our recent observations provide insights into the possible scenarios leading to irreparable chromosomal lesions and into the nature of these lesions, while introduction of genome analysis presents an opportunity to identify the most affected parts of the chromosome. Aim 1 of this study addresses specific mechanisms of chromosomal fragmentation, induced by hypoxanthine, uracil or fluorouracil. Aim 2 focuses on characterization of the mysterious origin DNA disappearance during thymine starvation, coinciding with thymineless death. Aim 3 tests our recently-proposed multi-stage model for thymineless death, which begins with stalling of the existing replication forks, proceeds through unknown number of intermediate stages and ends with the replication origin destruction. Collectively, this work will emphasize the importance to keep DNA precursor pools plentiful, balanced and sanitized by characterizing various sources of imbalance and contamination of the pools, as well as the chromosomal consequences, including irreparable lesions, that result from pool contamination and imbalance.