| Estimation of the Minimum Number of Replication Origins Per Chromosome in any Organism
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Author:
Date:
2020-10-20
[Abstract] Eukaryote nuclear genomes predominantly replicate through multiple replication origins. The number of replication origins activated per chromosome during the S-phase duration may vary according to many factors, but the predominant one is replication stress. Several studies have applied different approaches to estimate the number and map the positions of the replication origins in various organisms. However, without a parameter to restrict the minimum of necessary origins, less sensitive techniques may suggest conflicting results. The estimation of the minimum number of replication origins (MO) per chromosome is an innovative method that allows the establishment of a threshold, which serves as a parameter for genomic approaches that map origins. For this, the MO can be easily ...
[摘要] [摘要] 比率可能因多种因素而变化，但最主要的因素是复制应力。一些研究应用了不同的方法来估计复制源在不同生物体中的数量和位置。然而，如果没有一个参数来限制必要起源的最小值，那么不太敏感的技术可能会产生相互矛盾的结果。估计每个染色体的最小复制源数量（MO）是一种创新的方法，它允许建立一个阈值，作为绘制起源的基因组方法的参数。为此，MO可以很容易地通过一个公式得到，这个公式需要作为参数：染色体大小、S期持续时间和复制率。在基因组数据库（如NCBI）中可以获得任何生物体的染色体大小，通过监测DNA复制来估计S期的持续时间，并通过DNA组合方法获得复制率。 提供了一种简单、快速的估算MO的方法一个新的方法学框架来协助研究任何有机体。
关键词： DNA复制，复制来源，复制率，S期持续时间，染色体大小
[背景] ...
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| DNA Fiber Assay upon Treatment with Ultraviolet Radiations
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Author:
Date:
2017-06-05
[Abstract] Genome stability is continuously challenged by a wide range of DNA damaging factors. To promote a correct DNA repair and cell survival, cells orchestrate a coordinated and finely tuned cascade of events collectively known as the DNA Damage Response (DDR). Ultra Violet (UV) rays are among the main environmental sources of DNA damage and a well recognized cancer risk factor. UV rays induce the formation of toxic cyclobutane-type pyrimidine dimers (CPD) and [6-4]pyrimidine-pyrimidone (6-4PP) photoproducts which trigger the activation of the intra-S phase cell cycle checkpoint (Kaufmann, 2010) aimed at preventing replication fork collapse, late origin firing, and stabilizing fragile sites (Branzei and Foiani, 2009). To monitor the activation of the intra-S phase checkpoint in response to UV ...
[摘要] 基因组稳定性不断受到DNA损伤因素的广泛影响。为了促进正确的DNA修复和细胞存活，细胞协调统一称为DNA损伤反应（DDR）的协调和精细调整的事件级联。超紫外线（UV）是DNA损伤的主要环境来源之一，也是公认的癌症危险因素。紫外线诱导形成毒性环丁烷型嘧啶二聚体（CPD）和[6-4]嘧啶嘧啶酮（6-4PP）光产物，其触发S期细胞周期检查点的活化（Kaufmann，2010），目的在于防止复制叉崩溃，晚期起火和稳定脆弱场所（Branzei和Foiani，2009）。为了监测响应于UV型C（UVC）暴露的S-S相检查点的激活，DNA纤维测定可用于分析新的起始点和DNA合成速率（Jackson等， ，1998; Merrick等人，2004; Alfano等人，2016）。 DNA纤维测定技术在90年代被设想，然后通过使用并入新生DNA链中的胸苷类似物（如CldU和IdU）进一步开发。通过用这些类似物以连续模式处理细胞，可以通过携带不同荧光团的特异性抗体来观察细胞，可以监测复制叉活性并评估其如何受到紫外辐射或其他试剂的影响。
背景 ...
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| Single-molecule Analysis of DNA Replication Dynamics in Budding Yeast and Human Cells by DNA Combing
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Author:
Date:
2017-06-05
[Abstract] The DNA combing method allows the analysis of DNA replication at the level of individual DNA molecules stretched along silane-coated glass coverslips. Before DNA extraction, ongoing DNA synthesis is labeled with halogenated analogues of thymidine. Replication tracks are visualized by immunofluorescence using specific antibodies. Unlike biochemical and NGS-based methods, DNA combing provides unique information on cell-to-cell variations in DNA replication profiles, including initiation and elongation. Finally, this assay can be used to monitor the effect of DNA lesions on fork progression, arrest and restart.
[摘要] DNA梳理方法允许在沿着硅烷涂覆的玻璃盖玻片拉伸的单个DNA分子的水平上分析DNA复制。在DNA提取前，进行的DNA合成用胸苷的卤化类似物标记。使用特异性抗体通过免疫荧光可视化复制轨迹。与生物化学和基于NGS的方法不同，DNA梳理提供了DNA复制谱中细胞间细胞变化的独特信息，包括引发和延长。最后，该测定可用于监测DNA损伤对叉进展，停止和重新启动的影响。
背景 在称为复制起点的真核染色体上的数千个位点处启动DNA合成。原始激活遵循由检查点激酶和染色质的表观遗传修饰（Prioleau和MacAlpine，2016）控制的定义良好的复制计时程序。复制叉在正常S阶段经常停顿。叉停止是由多个事件引起的，例如DNA损伤，紧密结合的蛋白质复合物和高表达基因的转录（Tourriere和Pasero 2007; Zeman and Cimprich，2013）。真核生物已经制定了不同的策略来应对这种复制压力，包括修复机制来重新启动捕获的叉子和激活休眠复制起源以抢救终末抓捕的叉。
＆NBSP; ...
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