Gene Number: 1786

Location: 19p13.2

Key Functions: DNA methylation maintenance, epigenetic regulation, gene silencing

DNMT1 encodes DNA (cytosine-5)-methyltransferase 1, the central enzyme responsible for copying and maintaining DNA methylation patterns during DNA replication. Acting as the “guardian” of the epigenetic code, DNMT1 recognizes hemimethylated DNA strands and restores full methylation, ensuring that gene silencing and chromatin states are preserved with each cell division.

Functionally, DNMT1 serves as a molecular bridge between genomic stability and epigenetic inheritance. It maintains cellular identity by keeping key developmental and tissue-specific genes either active or repressed according to the cell’s lineage. DNMT1 also interacts with histone-modifying enzymes, chromatin remodeling complexes, and the replication machinery, coordinating methylation with nucleosome positioning and cell-cycle progression.

From a genetic and biomedical standpoint, mutations or altered expression of DNMT1 can disrupt the delicate balance of methylation, leading to aberrant gene silencing or activation of oncogenes. Such dysregulation is implicated in multiple human diseases, including cancer, neurological disorders, and imprinting syndromes.

Moreover, DNMT1 dysfunction contributes to global hypomethylation—a hallmark of genomic instability—as well as locus-specific hypermethylation that silences tumor suppressor genes.

In essence, DNMT1 operates as the epigenetic memory keeper of the genome, ensuring that the molecular signatures defining cellular function and identity are faithfully transmitted through generations of cells, while errors in its regulation can reprogram the epigenome toward disease.