Luda Shlyaktenko, Chris Woodcock (2010) CIL:7107, 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DNA甲基化模式中编码的（通常）抑制信号。MeCP2基因突变导致雷特综合症。在此，采用空气环境下的原子力显微镜（Digital Instruments Nanoscope）对含有多个甲基化CpG的人源MeCP2和828碱基对的DNA序列的MeCP2-DNA复合物进行了成像。MeCP2分子在原子力显微镜图像中呈现为明亮的颗粒。复合物的体积测量表明，MeCP2单体（圆形颗粒）和二聚体（较大椭圆颗粒）的存在，并暗示MeCP2与DNA的协同结合。组集中的其他图像展示了环状结构和包含多条DNA链和MeCP2分子的较大复合物。这些构型可能由MeCP2的多个独立的DNA结合域所促进，并与MeCP2与染色质在体内的相互作用相关。