Luda Shlyaktenko, Chris Woodcock (2010) CIL:7118, Homo sapiens, neuron. CIL. Dataset

The protein MeCP2 binds to symmetrically methylated CpG dinucleotides and is thought to transmit the (generally) repressive signals encoded in DNA methylation patterns. Mutations in MeCP2 lead to Rett syndrome. Here, MeCP2-DNA complexes have been imaged by AFM (Digital Instruments Nanoscope) in air using human MeCP2 and an 828 bp DNA sequence containing several methylated CpGs. MeCP2 molecules appear as bright particles in AFM images. Volume measurements of the complexes suggest that MeCP2 monomers (circular particles) and dimers (larger elliptical particles) are present and suggest that MeCP2 binds DNA cooperatively. Other images in the grouped set show looped structures and large complexes containing multiple DNA strands and MeCP2 molecules. These configurations are likely promoted by the multiple independent DNA-binding domains of MeCP2 and relevant to the in vivo interactions between MeCP2 and chromatin.

蛋白质 MeCP2 与对称甲基化的 CpG 二核苷酸结合，并被认为传递编码在 DNA 甲基化模式中的（通常）抑制信号。MeCP2 基因的突变会导致雷特综合征。在本研究中，使用人体 MeCP2 和包含多个甲基化 CpG 的 828 bp DNA 序列，通过原子力显微镜（Digital Instruments Nanoscope）在空气中对 MeCP2-DNA 复合物进行了成像。在原子力显微镜图像中，MeCP2 分子呈现为明亮的颗粒。复合物的体积测量表明，存在 MeCP2 单体（圆形颗粒）和二聚体（较大的椭圆形颗粒），并暗示 MeCP2 与 DNA 的结合是协同的。组图中其他图像显示了环状结构和包含多个 DNA 链和 MeCP2 分子的大型复合物。这些构型可能由 MeCP2 的多个独立的 DNA 结合域促进，并与其与染色质的体内相互作用相关。