# DNMT1 (DNA methyltransferase 1)

Source: https://onco.cc/targets/dnmt1/  
OnCo record `dnmt1` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The enzyme that copies methylation marks onto newly made DNA, keeping genes silenced. Azacitidine and decitabine trap and destroy it, waking silenced tumour suppressor genes in blood cancers.

## Summary

DNMT1 maintains DNA methylation by copying the pattern from the parent strand to the new strand after replication. Azacitidine and decitabine are cytidine analogues incorporated into DNA that covalently trap DNMT1, which is then degraded, so methylation is lost over successive cell divisions and silenced genes are re-expressed; at higher doses they are also directly cytotoxic. They are standard treatment for higher-risk myelodysplastic syndromes and, with venetoclax, for older or unfit patients with acute myeloid leukaemia. Oral decitabine with cedazuridine matches intravenous exposure.

## Fields

- Kind: Target
- Last checked: 2026-09-04
- Symbol: DNMT1
- Class: enzyme
- Biology: Maintenance DNA methyltransferase acting at hemimethylated CpG sites after replication; covalently trapped by incorporated azacytosine.
- Where found: Myelodysplastic syndromes; Acute myeloid leukaemia; Chronic myelomonocytic leukaemia

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/DNMT1
- UniProt P26358: DNMT1: https://www.uniprot.org/uniprotkb/P26358/entry

## Connected records

- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [Chronic myelomonocytic leukaemia and MDS/MPN overlap neoplasms](https://onco.cc/cancers/cmml/), [Myelodysplastic syndromes / neoplasms (MDS)](https://onco.cc/cancers/mds/)
- drugs: [Azacitidine](https://onco.cc/drugs/azacitidine/), [Decitabine](https://onco.cc/drugs/decitabine/)
- targets: [DNA methyltransferase 3A (DNMT3A)](https://onco.cc/targets/dnmt3a/)

---
JSON: https://onco.cc/api/v1/entities/dnmt1.json