BACKGROUND MeCP2 and MBD2 are members of a family of proteins that possess a domain that selectively binds 5-methylcytosine in a CpG context. Members of the family interact with other proteins to modulate DNA packing. Stretching of DNA-protein complexes in nanofluidic channels with a cross-section of a few persistence lengths allows us to probe the degree of compaction by proteins. RESULTS We demonstrate DNA compaction by MeCP2 while MBD2 does not affect DNA configuration. By using atomic force microscopy (AFM), we determined that the mechanism for compaction by MeCP2 is the formation of bridges between distant DNA stretches and the formation of loops. CONCLUSIONS Despite sharing a similar specific DNA-binding domain, the impact of full-length 5-methylcytosine-binding proteins can vary drastically between strong compaction of DNA and no discernable large-scale impact of protein binding. We demonstrate that ATTO 565-labeled MBD2 is a good candidate as a staining agent for epigenetic mapping.

中文翻译：

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由两个5-甲基胞嘧啶结合蛋白进行的DNA环化，使用纳米流体装置进行定量。

背景技术MeCP2和MBD2是蛋白质家族的成员，该蛋白质家族具有在CpG背景下选择性结合5-甲基胞嘧啶的结构域。该家族成员与其他蛋白质相互作用以调节DNA堆积。DNA-蛋白质复合物在纳米流体通道中具有几个持续性长度的横截面的拉伸使我们能够探究蛋白质的紧缩程度。结果我们证明了MeCP2可以压实DNA，而MBD2不会影响DNA构型。通过使用原子力显微镜（AFM），我们确定了MeCP2压实的机制是遥远的DNA延伸之间的桥的形成和环的形成。结论尽管共享相似的特定DNA结合域，全长5-甲基胞嘧啶结合蛋白的影响在DNA的紧密压实与蛋白结合没有明显的大规模影响之间会发生巨大变化。我们证明，ATTO 565标记的MBD2是作为表观遗传作图的染色剂的良好候选者。