Direct real-time molecular scale visualisation of the degradation of condensed DNA complexes exposed to DNase I
Direct real-time molecular scale visualisation of the degradation of condensed DNA complexes exposed to DNase I
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DOI：
10.1093/nar/gkg462
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发表时间：
2003-07-15
影响因子：
14.9
通讯作者：
Williams, PM
中科院分区：
文献类型：
--
作者：
Abdelhady, HG;Allen, S;Williams, PM
保护DNA免于体内降解的需要是治疗性基因递送的基本原则之一，也是任何提议的递送载体的标准测试。然而，目前采用的体外试验目前没有提供载体复合物的分子结构与它们在该作用中的成功之间的直接联系，因此阻碍了成功的基因递送剂的合理设计。在这里，我们应用原子力显微镜（AFM）在液体中可视化在分子尺度上，并在真实的时间，DNA酶I对第4代聚酰胺胺树枝状聚合物（G4）与DNA复合的效果。这些复合物被揭示为在性质上是动态的，显示出一定程度的流动性，在某些情况下，揭示了树枝状聚合物的添加和损失的个别复合物。观察到G4-DNA复合物的形成为DNA提供了一定程度的保护。这种保护与所形成的复合物的结构形态有关，所形成的复合物的结构形态本身被证明取决于树枝状聚合物负载和复合物形成所允许的时间。
The need to protect DNA from in vivo degradation is one of the basic tenets of therapeutic gene delivery and a standard test for any proposed delivery vector. The currently employed in vitro tests, however, presently provide no direct link between the molecular structure of the vector complexes and their success in this role, thus hindering the rational design of successful gene delivery agents. Here we apply atomic force microscopy (AFM) in liquid to visualise at the molecular scale and in real time, the effect of DNase I on generation 4 polyamidoamine dendrimers (G4) complexed with DNA. These complexes are revealed to be dynamic in nature showing a degree of mobility, in some cases revealing the addition and loss of dendrimers to individual complexes. The formation of the G4-DNA complexes is observed to provide a degree of protection to the DNA. This protection is related to the structural morphology of the formed complex, which is itself shown to be dependent on the dendrimer loading and the time allowed for complex formation.