Luda Shlyaktenko, Chris Woodcock (2010) CIL:7114, 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，并被认为能够传递DNA甲基化模式中编码的（通常）抑制信号。MeCP2基因突变会导致Rett综合征。在本研究中，通过原子力显微镜（Digital Instruments Nanoscope）在空气中，使用人源MeCP2和包含多个甲基化CpG的828碱基对DNA序列，对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，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以协同方式与DNA结合。组图中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。这些结构很可能由MeCP2的多个独立DNA结合域促进，并与MeCP2与染色质的体内相互作用相关。