A Link between ORC-origin binding mechanisms and origin activation time revealed in budding yeast.
A Link between ORC-origin binding mechanisms and origin activation time revealed in budding yeast.
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DOI：
10.1371/journal.pgen.1003798
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发表时间：
2013
期刊：
影响因子：
4.5
通讯作者：
Fox CA
中科院分区：
文献类型：
--
作者：
Hoggard T;Shor E;Müller CA;Nieduszynski CA;Fox CA
当起始点识别复合物（ORC）结合染色体位置并触发最终启动DNA复制的分子事件时，真核DNA复制起始点在G1期被选择（a.k.a.在S阶段期间的原点点火）。每条染色体使用多个起点进行复制，并且每个起点在S期的特征时间激发，产生与分化和基因组稳定性相关的细胞类型特异性基因组复制模式。目前尚不清楚ORC-起源相互作用是否与起源激活时间相关。我们应用了一种新的全基因组策略，分类的基础上用于ORC-起源结合的分子相互作用的类型的模型真核生物酿酒酵母的起源。具体而言，当ORC-起源在体内的结合强度可以通过ORC对起源DNA的体外亲和力来解释时，起源被归类为DNA依赖性的，并且相反地，当ORC-DNA在体外的相互作用不足以解释ORC-起源在体内的结合强度时，被归类为“染色质依赖性的”。这两个起源类别不同的核小体架构和依赖于起始侧翼序列在质粒复制试验中，与染色质促进ORC结合的本地功能在'染色质依赖性'的起源。最后，“染色质依赖”类丰富的起源，火灾早期在S-阶段，而DNA依赖类丰富的点火起源。相反，最新的发射源显示出与ORC起源DNA范式的正常水平的ORC结合的正相关，而最早的发射源没有。这些数据揭示了ORC-起源结合机制和起源激活时间调节之间的新关联。细胞分裂需要染色体的复制，蛋白质-DNA复合物携带遗传信息。特定的染色体位置，起源，启动这种复制。准确、有效的复制需要多个来源--数量不足会导致遗传物质的错误和疾病，如癌症。当起始点识别复合物（ORC）与它们结合时，起始点被选择。控制这种结合的分子相互作用尚不清楚。了解这些相互作用将导致控制细胞分裂的新方法，这可能有助于疾病的治疗。在真核微生物芽殖酵母中进行实验以定义ORC用于结合起源的分子相互作用的类型。酵母对这些研究很有用，因为从酵母到人类，染色体复制和结构都很保守。虽然ORC-DNA相互作用很重要，但ORC与染色体蛋白之间的相互作用也发挥了作用。此外，不同的来源依赖于与ORC的不同类型的分子相互作用。最后，ORC-蛋白质相互作用而不是ORC-DNA相互作用与染色体复制过程中增强的起源功能相关，揭示了ORC用于选择起源的分子相互作用类型与该起源的最终功能之间的意外联系。这些结果对干扰ORC-起源相互作用以控制细胞分裂具有意义。
Eukaryotic DNA replication origins are selected in G1-phase when the origin recognition complex (ORC) binds chromosomal positions and triggers molecular events culminating in the initiation of DNA replication (a.k.a. origin firing) during S-phase. Each chromosome uses multiple origins for its duplication, and each origin fires at a characteristic time during S-phase, creating a cell-type specific genome replication pattern relevant to differentiation and genome stability. It is unclear whether ORC-origin interactions are relevant to origin activation time. We applied a novel genome-wide strategy to classify origins in the model eukaryote Saccharomyces cerevisiae based on the types of molecular interactions used for ORC-origin binding. Specifically, origins were classified as DNA-dependent when the strength of ORC-origin binding in vivo could be explained by the affinity of ORC for origin DNA in vitro, and, conversely, as ‘chromatin-dependent’ when the ORC-DNA interaction in vitro was insufficient to explain the strength of ORC-origin binding in vivo. These two origin classes differed in terms of nucleosome architecture and dependence on origin-flanking sequences in plasmid replication assays, consistent with local features of chromatin promoting ORC binding at ‘chromatin-dependent’ origins. Finally, the ‘chromatin-dependent’ class was enriched for origins that fire early in S-phase, while the DNA-dependent class was enriched for later firing origins. Conversely, the latest firing origins showed a positive association with the ORC-origin DNA paradigm for normal levels of ORC binding, whereas the earliest firing origins did not. These data reveal a novel association between ORC-origin binding mechanisms and the regulation of origin activation time. Cell division requires the duplication of chromosomes, protein-DNA complexes harboring genetic information. Specific chromosomal positions, origins, initiate this duplication. Multiple origins are required for accurate, efficient duplication—an insufficient number leads to mistakes in the genetic material and pathologies such as cancer. Origins are chosen when the origin recognition complex (ORC) binds to them. The molecular interactions controlling this binding remain unclear. Understanding these interactions will lead to new ways to control cell division, which could aid in treatments of disease. Experiments were performed in the eukaryotic microbe budding yeast to define the types of molecular interactions ORC uses to bind origins. Yeasts are useful for these studies because chromosome duplication and structure are well conserved from yeast to humans. While ORC-DNA interactions were important, interactions between ORC and chromosomal proteins played a role. In addition, different origins relied on different types of molecular interactions with ORC. Finally, ORC-protein interactions but not ORC-DNA interactions were associated with enhanced origin function during chromosome-duplication, revealing an unanticipated link between the types of molecular interactions ORC uses to select an origin and the ultimate function of that origin. These results have implications for interfering with ORC-origin interactions to control cell division.
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影响因子：
21.3
作者：
Feng, Wenyi;Collingwood, David;Boeck, Max E;Fox, Lindsay A;Alvino, Gina M;Fangman, Walton L;Raghuraman, Mosur K;Brewer, Bonita J
通讯作者：
Brewer, Bonita J
DOI：
10.1098/rstb.2011.0073
发表时间：
2011-12-27
期刊：
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
影响因子：
--
作者：
Diffley JF
通讯作者：
Diffley JF
影响因子：
14.9
作者：
Chang F;May CD;Hoggard T;Miller J;Fox CA;Weinreich M
通讯作者：
Weinreich M
影响因子：
4.8
作者：
Chastain, PD;Bowers, JL;Griffith, JD
通讯作者：
Griffith, JD
影响因子：
4.5
作者：
Donato JJ;Chung SC;Tye BK
通讯作者：
Tye BK