DNA methylation pathway

The **DNA methylation pathway** is an essential epigenetic mechanism involving the covalent addition of a methyl group to the 5-position of cytosine residues within CpG dinucleotides. This process is catalyzed by a family of enzymes known as **DNA methyltransferases**—primarily DNMT1, DNMT3A, and DNMT3B—which regulate both maintenance and de novo establishment of these marks during cell division and development. Methylated cytosines can alter chromatin structure directly or indirectly by recruiting proteins that recognize these modifications (“readers” such as MBD proteins), leading to transcriptional repression or activation depending on context. The patterning established by this pathway plays critical roles in regulating gene expression programs during embryogenesis, cellular differentiation, X-chromosome inactivation, genomic imprinting, aging processes, neurogenesis, immune function regulation—and is frequently dysregulated in human disease. Aberrant activity within the DNA methylation pathway contributes significantly to carcinogenesis through inappropriate silencing of tumor suppressor genes via promoter hypermethylation or genome-wide hypomethylation resulting in chromosomal instability. As such it has become both a **therapeutic target**—with drugs like azacitidine/decitabine approved for certain hematologic malignancies—and an important source for diagnostic/prognostic biomarkers across multiple disease areas including solid tumors and neurological disorders. However—as this entry refers not to a single molecular entity but rather an entire enzymatic/epigenetic process—it should be noted that “DNA methylation pathway” does not correspond precisely to one canonical druggable target but rather encompasses several related molecular targets within its network.[2][3][6][8]

Other names

DNA methylationEpigenetic methylation pathwayCpG methylation pathway

– Inhibition of DNA methyltransferase enzymes to reduce or reverse abnormal gene silencing by demethylating tumor suppressor genes or other regulatory elements[5]