MBD2‐MBD3 complex binds to hemi‐methylated DNA and forms a complex containing DNMT1 at the replication foci in late S phase

摘要: Background In vertebrates and plants, DNA methylation is one of the major mechanisms regulating gene expression. Recently, a family methyl-CpG-binding proteins has been identified, some members, such as MeCP2 MBD2, were shown to mediate repression by recruiting histone deacetylase complexes methylated genes. However, function another member this family, MBD3, remained elusive. Results It was that MBD2 MBD3 form homo- hetero-dimers (or multimers) in vitro vivo. Significantly, MBD2-MBD3 complex showed an affinity hemi-methylated DNAs, property never reported with any proteins. co-localized DNMT1 at replication foci 293 cell nuclei late S phase. Moreover, co-immunoprecipitation experiment, MBD3. Finally, abundance highest phase when also most abundant, whereas level largely constant throughout cycle. Conclusions The results suggest may play important role We hypothesize recognizes concurrent recruits complexes, well DNMT1, establish and/or maintain transcriptionally repressed chromatin.