Ballestar E, Yusufzai T M, Wolffe A P
National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-5431, USA.
Biochemistry. 2000 Jun 20;39(24):7100-6. doi: 10.1021/bi0001271.
We have investigated the properties of mutant forms of the methyl-CpG binding transcriptional repressor MeCP2 associated with Rett syndrome, a childhood neurodevelopmental disorder. We find that four Rett syndrome mutations at known sites within the methyl-CpG binding domain (MBD) impair binding to methylated DNA, but have little effect on nonspecific interactions with unmethylated DNA. Three of these mutations (R106W, R133C, and F155S) have their binding affinities for methylated DNA reduced more than 100-fold; this is consistent with the hypothesis that impaired selectivity for methylated DNA of mutant MeCP2 contributes to Rett syndrome. However, a fourth mutant, T158M, has its binding affinity for methylated DNA reduced only 2-fold, indicative either of additional distinct regulatory functions associated with the MBD or of an exquisite sensitivity of developing neurons to the selective association of MeCP2 with methylated DNA.
我们研究了与雷特综合征（一种儿童神经发育障碍）相关的甲基化CpG结合转录抑制因子MeCP2突变体形式的特性。我们发现，甲基化CpG结合结构域（MBD）内已知位点的四个雷特综合征突变会损害与甲基化DNA的结合，但对与未甲基化DNA的非特异性相互作用影响很小。其中三个突变（R106W、R133C和F155S）对甲基化DNA的结合亲和力降低了100倍以上；这与突变型MeCP2对甲基化DNA的选择性受损导致雷特综合征的假设一致。然而，第四个突变体T158M对甲基化DNA的结合亲和力仅降低了2倍，这表明MBD可能具有额外的独特调节功能，或者发育中的神经元对MeCP2与甲基化DNA的选择性结合具有极高的敏感性。
