Structure of the replication foci-targeting sequence of human DNA cytosine methyltransferase DNMT1
[DNMT1_HUMAN] Defects in DNMT1 are the cause of hereditary sensory neuropathy type 1E (HSN1E) [MIM:614116]. A neurodegenerative disorder characterized by adult onset of progressive peripheral sensory loss associated with progressive hearing impairment and early-onset dementia.
[DNMT1_HUMAN] Methylates CpG residues. Preferentially methylates hemimethylated DNA. Associates with DNA replication sites in S phase maintaining the methylation pattern in the newly synthesized strand, that is essential for epigenetic inheritance. Associates with chromatin during G2 and M phases to maintain DNA methylation independently of replication. It is responsible for maintaining methylation patterns established in development. DNA methylation is coordinated with methylation of histones. Mediates transcriptional repression by direct binding to HDAC2. In association with DNMT3B and via the recruitment of CTCFL/BORIS, involved in activation of BAG1 gene expression by modulating dimethylation of promoter histone H3 at H3K4 and H3K9.  
Publication Abstract from PubMed
Dnmt1 (DNA methyltransferase 1) is the principal enzyme responsible for maintenance of cytosine methylation at CpG dinucleotides in the mammalian genome. The N-terminal replication focus targeting sequence (RFTS) domain of Dnmt1 has been implicated in subcellular localization, protein association, and catalytic function. However, progress in understanding its function has been limited by the lack of assays for and a structure of this domain. Here, we show that the naked DNA- and polynucleosome-binding activities of Dnmt1 are inhibited by the RFTS domain, which functions by virtue of binding the catalytic domain to the exclusion of DNA. Kinetic analysis with a fluorogenic DNA substrate established the RFTS domain as a 600-fold inhibitor of Dnmt1 enzymatic activity. The crystal structure of the RFTS domain reveals a novel fold and supports a mechanism in which an RFTS-targeted Dnmt1-binding protein, such as Uhrf1, may activate Dnmt1 for DNA binding.
The replication focus targeting sequence (RFTS) domain is a DNA-competitive inhibitor of Dnmt1.,Syeda F, Fagan RL, Wean M, Avvakumov GV, Walker JR, Xue S, Dhe-Paganon S, Brenner C J Biol Chem. 2011 Apr 29;286(17):15344-51. Epub 2011 Mar 9. PMID:21389349
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.