Interaction of G-Quadruplexes in the Full-Length 3′ Human Telomeric Overhang
Interaction of G-Quadruplexes in the Full-Length 3′ Human Telomeric Overhang
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DOI：
10.1021/ja510079u
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发表时间：
2014-12-31
影响因子：
15
通讯作者：
Mao, Hanbin
中科院分区：
文献类型：
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作者：
Punnoose, Jibin Abraham;Cui, Yunxi;Mao, Hanbin
端粒3'端的突出端为G-四链体的形成和相互作用提供了充足的机会，G-四链体已经显示出对包括端粒区域的端粒酶活性在内的许多生物学功能的影响。然而，在对接近人类端粒突出端全长的DNA构建的少数调查中，高阶quadruplexquadruplex相互作用的存在仍然是一个争论的主题。本文中，我们采用动态夹板连接（DSL）来制备DNA构建体5 ′-（TTAGGG）（24）或24 G，其具有与3 ′人端粒突出端的完整延伸相当的长度。在激光镊子中使用机械展开分析，我们观察到G-四链体之间的高阶相互作用的少数群体（类似于5%），而大多数的四链体遵循串珠模型。对24 G构建体中非相互作用的G-四链体的分析显示出与5 '-（TTAGGG）4（4G）构建体中独立的G-四链体相似的特征。由于每个24 G构建体含有多达6个G-四链体，因此该方法为非B DNA结构的耗时机械解折叠实验提供了更高的通量。
The 3' human telomeric overhang provides ample opportunities for the formation and interaction of G-quadruplexes, which have shown impacts on many biological functions including telomerase activities in the telomere region. However, in the few investigations on DNA constructs that approach to the full length of the human telomeric overhang, the presence of higher-order quadruplexquadruplex interactions is still a subject of debate. Herein, we employed dynamic splint ligation (DSL) to prepare a DNA construct, 5'-(TTAGGG)(24) or 24G, which has the length comparable to the full stretch of 3' human telomeric overhang. Using mechanical unfolding assays in laser tweezers, we observed a minor population (similar to 5%) of higher-order interactions between G-quadruplexes, while the majority of the quadruplexes follow the bead-on-a-string model. Analyses on the noninteracting G-quadruplexes in the 24G construct showed features similar to those of the stand-alone G-quadruplexes in the 5'-(TTAGGG)4 (4G) construct. As each 24G construct contains as many as six G-quadruplexes, this method offers increased throughput for the time-consuming mechanical unfolding experiments of non-B DNA structures.