The MeCP1 complex represses transcription through preferential binding, remodeling, and deacetylating methylated nucleosomes

Histone deacetylation plays an important role in methylated DNA silencing. Recent studies indicated that the methyl-CpG-binding protein, MBD2, is a co mponent of the MeCP1 histone deacetylase complex. Interestingly, MBD2 is ab le to recruit the nucleosome remodeling and histone deacetylase, NuRD, to m ethylated DNA in vitro. To understand the relationship between the MeCP1 co mplex and the NuRD complex, we purified the MeCP1 complex to homogeneity an d found that it contains 10 major polypeptides including MBD2 and all of th e known NuRD components. Functional analysis of the purified MeCP1 complex revealed that it preferentially binds, remodels, and deacetylates methylate d nucleosomes. Thus, our study defines the MeCP1 complex, and provides bioc hemical evidence linking nucleosome remodeling and histone deacetylation to methylated gene silencing.