The Methyl-CpG Binding Transcriptional Repressor MeCP2 Stably Associates with Nucleosomal DNA

We have investigated the interactions of the methyl-CpG binding transcriptional repressor MeCP2 with nucleosomal DNA. We find that MeCP2 forms discrete complexes with nucleosomal DNA associating with methyl-CpGs exposed in the major groove via the methyl-CpG-binding domain (MBD). In addition to the MBD, the carboxyl-terminal segment of MeCP2 facilitates binding both to naked DNA and to the nucleosome core. These observations provide a molecular mechanism by which MeCP2 can gain access to chromatin in order to target corepressor complexes that further modify chromatin structure.