The mysteries of telomere structure and recognition: could radioprobing help?
The mysteries of telomere structure and recognition: could radioprobing help?
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端粒结构和识别之谜：放射探测有帮助吗？
DOI：
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发表时间：
2004
影响因子：
2.6
通讯作者：
H. Nikjoo
中科院分区：
文献类型：
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作者：
C. Laughton;C. Grindon;P. Girard;H. Nikjoo
目的：端粒是在真核生物染色体末端发现的特殊的DNA -蛋白质复合物。在正常的体细胞中，随着细胞的分裂，它们变得更短，似乎控制着它们的复制寿命。然而，几乎所有肿瘤都表现出端粒酶的激活，端粒酶是一种特殊的逆转录酶/DNA聚合酶，它可以在染色体末端添加新的端粒重复序列，这似乎是细胞永生过程中的关键因素。因此，目前对端粒延伸抑制剂在癌症治疗中的潜力有很大的兴趣。一些研究小组已经发现，有可能产生针对端粒重复（底物）DNA而不是端粒酶本身的抑制分子。这被认为是有效的，因为已经发现在体外，这些DNA序列可以折叠成药物识别和稳定的四链（四重体）结构，但不被酶识别。然而，尽管药物化学家继续在这一假设的基础上进行合理的设计方案，但目前很少有证据表明这些结构在体内形成，并且在体内药物通过与它们结合而起作用。因此，获得端粒酶抑制剂与DNA在何处以及如何相互作用的确凿证据，是对它们的作用机制和有效药物开发的基本理解的迫切关注。材料和方法：放射性探针是研究DNA结构的一种有价值的新方法。最近，我们通过计算机模拟放射探测表明，该技术是一种非常敏感的DNA构象细节探测技术。在这里，我们报告了我们对一种放射性标记的端粒酶抑制剂（与诺丁汉大学正在开发的一类新型抑制剂有关）与端粒DNA多种可能结构结合的模拟。结果与结论：预测的切割模式对DNA结构和药物结合方式非常敏感。这些结果表明，放射性探测实验应该能够为端粒-药物复合物的“真实”性质提供明确的证据，从而有助于合理的设计方案。
Purpose: Telomeres are specialized DNA‐protein complexes found at the ends of eukaryotic chromosomes. In normal somatic cells these become shorter with each cell division and appear to control their replicative lifespan. However almost all tumours show activation of the enzyme telomerase, a specialised reverse transcriptase/DNA polymerase, that can add new telomeric repeats to the ends of chromosomes and this appears to be a key factor in the cell immortalization process. Consequently there is much current interest in the potential for inhibitors of telomere extension in the treatment of cancer. Several groups have found that it is possible to produce inhibitory molecules that target the telomeric repeat (substrate) DNA rather than the telomerase enzyme itself. This is thought to work because it has been found that in vitro, these DNA sequences can fold up into a four‐stranded (quadruplex) structure that the drugs recognise and stabilize, but which is not recognised by the enzyme. However, while medicinal chemists continue to base rational design programs on this hypothesis, there is currently very little evidence that these structures form in vivo, and that in vivo the drugs work by binding to them. To have incontrovertible evidence of where and how these telomerase inhibitors and DNA interact is therefore a pressing concern for a basic understanding of their mechanism of action and effective drug development. Materials and methods: Radioprobing represents a valuable new approach to the study of DNA structures. Recently we have shown through computer simulations of radioprobing that the technique is a remarkably sensitive probe of quite fine details of DNA conformation. Here we report on our simulations of the binding of a radiolabelled telomerase inhibitor, related to a class of novel inhibitors under development at Nottingham, to a variety of possible structures for telomeric DNA. Results and Conclusions: The predicted cleavage patterns prove to be very sensitive to the DNA structure, and the mode of binding of the drug. These results suggest that radioprobing experiments should be able to provide unambiguous evidence as to the ‘true’ nature of the telomere‐drug complexes, and so aid the rational design programme.