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DNA demethylation pathways: Additional players and regulators
Author(s) -
Bochtler Matthias,
Kolano Agnieszka,
Xu GuoLiang
Publication year - 2017
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.201600178
Subject(s) - dna demethylation , dna glycosylase , base excision repair , deamination , biology , dna methylation , nucleotide excision repair , cytosine , dna repair , dna , 5 methylcytosine , biochemistry , enzyme , gene , gene expression
DNA demethylation can occur passively by “dilution” of methylation marks by DNA replication, or actively and independently of DNA replication. Direct conversion of 5‐methylcytosine (5mC) to cytosine (C), as originally proposed, does not occur. Instead, active DNA methylation involves oxidation of the methylated base by ten‐eleven translocations (TETs), or deamination of the methylated or a nearby base by activation induced deaminase (AID). The modified nucleotide, possibly together with surrounding nucleotides, is then replaced by the BER pathway. Recent data clarify the roles and the regulation of well‐known enzymes in this process. They identify base excision repair (BER) glycosylases that may cooperate with or replace thymine DNA glycosylase (TDG) in the base excision step, and suggest possible involvement of DNA damage repair pathways other than BER in active DNA demethylation. Here, we review these new developments.