Summary

Maintenance DNA methylation is a process of vital importance in the development of animals and to the prevention of disease. mDNMT1 is the enzyme responsible for maintaining the inherent methylation pattern  during DNA replication in mice. Two crystal structures of mDNMT1 have been determined. The autoinhibitory and the productive complex. These two complexes are brought together to form a complementary mechanism which allows the enzyme  efficiently pass methylation pattern to the daughter cells after each round of replication.

 The autoinhibitory complex protects CpG sites which should not be methylated from De Novo methylation. Differently, the productive complex through the TRD domains recognize the correct targets and performs maintenance methylation to hemimethylated CpG sites exiting the replication fork.The two mechanisms work paralelly and complement each other together with other regulatory proteinss (i.e UHFR) which guaranty the faithfull maintenance of DNAmethylationpaterns.