[Functional significance of MeCP2 mutations in patients with Rett syndrome]

Mutations in the MeCP2 gene cause Rett syndrome and are observed in approximately 80% of Rett syndrome patients. To investigate the functional significance of these mutations, we established two functional assays using transient expression systems. Transcriptional repressive activities of MeCP2 mutants were analyzed by the reporter assay in Drosophila cells. The influences of mutations on methyl-CpG-binding activities were indirectly assessed by examining the affinity of fluorescent labelled mutant proteins to mouse heterochromatins, where approximately one half of all methyl-CpG-base pairs are located. These functional assays are useful in evaluating mutations in the methyl-CpG-binding domain of MeCP2 and will provide insight into the relationship between the genotype and the phenotype of Rett syndrome.