DNA碱基甲基化对碱基间相互作用和DNA构象以及DNA-蛋白质结合的影响

比较了采用量子化学从头算方法(ab initio)计算的非甲基化-甲基化DNA碱基间的氢键和堆积作用.结果表明,碱基甲基化损伤减弱了碱基间的氢键作用能,但使堆积作用能增大.应用自然键轨道(NBO)理论,分析了采用M062x/6-31+G(d,p)算法优化的C5-甲基胞嘧啶(C5-MeC)和O6-甲基鸟嘌呤(O6-MeG)与非甲基化碱基间的氢键结构.NBO分析揭示,甲基插入O6-G,改变了授受体作用方式,产生的空间障碍使cis-O6MeG…C的N1(G)…HN4(C)的距离增大,nN1(G)的电荷迁移能力减小,导致cis-O6MeG…C的氢键作用能小于anti-O6MeG…C.采用分子动力学方法 (MD)模拟了IBRCA基因启动子区富CpG序列中12mer的寡聚体,分析了CpG甲基化(mCpG)对DNA双链体构象的影响.结果表明,不同位点的mCpG,对DNA双链体平面内的碱基对结构基本没有影响,但CpG段的堆积结构参数以及DNA大小沟的宽度和深度发生了不同程度的改变.还进一步分析了mCpG对K50型同源域转录因子PITX2与DNA相互作用的影响.得到的结论与文献基本一致.     

未来电脑、生命科学与DNA

简要介绍了未来电脑（光子电脑、量子电脑、生物电脑）的基本概念和发展前景，阐述了生命科学与税氧核糖核酸（即DNA）的有关知识。     

Genomics, gene expression and DNA arrays

Experimental genomics in combination with the growing body of sequence information promise to revolutionize the way cells and cellular processes are studied. Information on genomic sequence can be used experimentally with high-density DNA arrays that allow complex mixtures of RNA and DNA to be interrogated in a parallel and quantitative fashion. DNA arrays can be used for many different purposes, most prominently to measure levels of gene expression (messenger RNA abundance) for tens of thousands of genes simultaneously. Measurements of gene expression and other applications of arrays embody much of what is implied by the term 'genomics'; they are broad in scope, large in scale, and take advantage of all available sequence information for experimental design and data interpretation in pursuit of biological understanding.     

DNA end resection, homologous recombination and DNA damage checkpoint activation require CDK1

A single double-strand break (DSB) induced by HO endonuclease triggers both repair by homologous recombination and activation of the Mec1-dependent DNA damage checkpoint in budding yeast. Here we report that DNA damage checkpoint activation by a DSB requires the cyclin-dependent kinase CDK1 (Cdc28) in budding yeast. CDK1 is also required for DSB-induced homologous recombination at any cell cycle stage. Inhibition of homologous recombination by using an analogue-sensitive CDK1 protein results in a compensatory increase in non-homologous end joining. CDK1 is required for efficient 5' to 3' resection of DSB ends and for the recruitment of both the single-stranded DNA-binding complex, RPA, and the Rad51 recombination protein. In contrast, Mre11 protein, part of the MRX complex, accumulates at unresected DSB ends. CDK1 is not required when the DNA damage checkpoint is initiated by lesions that are processed by nucleotide excision repair. Maintenance of the DSB-induced checkpoint requires continuing CDK1 activity that ensures continuing end resection. CDK1 is also important for a later step in homologous recombination, after strand invasion and before the initiation of new DNA synthesis.     

preMiDTM:血浆突变检测技术新平台

随着分子生物学技术的发展,癌症分子特征方面的研究得以不断深入。本文旨在探讨肿瘤相关基因突变的研究发展对癌症早期发现的重要意义,介绍原创preMiDTM血浆循环突变检测技术平台及其临床应用前景。     

The electronic structures, magnetism and metastable states of DNA

Molecular devices are the ultimate goal in the miniaturization of the electronic technology. Based on the unique properties of DNA (e.g. self-assembly and molecular recognition), people have made great efforts to develop molecular devices in the last few …     

赖解旋酶恒温基因扩增技术的原理、应用和展望

赖解旋酶恒温基因扩增方法(HDA法)是新近发明的一种简便、快速、高效的体外恒温基因扩增技术.该法依靠DNA解旋酶解开双链DNA、单链DNA结合蛋白(SSB)维持单链状态、DNA聚合酶催化靶片段的扩增.研究表明,HDA能扩增微生物基因组DNA、病原菌DNA、质粒DNA和cDNA等,从灵敏性、准确性和可操作性几方面看,该方法具有广阔的实用前景.     

DNA芯片--世纪之交的技术革命

ＤＮＡ 芯片是以硅、玻璃等材料作固相载片,应用计算机、半导体、光化学合成等微加工技术,将数十万个寡核苷酸片段高密度集成于１ｃｍ ２ 左右的芯片上．它可以作为微反应进行ＰＣＲ、ＬＣＲ等反应,尤其是芯片上的探针列阵可用于检测人类遗传病的基因变异,加速人类基因组的研究及为临床医学开辟新路．ＤＮＡ 芯片有望成为研究生命信息的一种新的有力工具．