Gene: DNMT3A
UniProt: Q9Y6K1
Molecular Weight: ~130 kDa
Subcellular Localization: Nucleus
Protein Family: DNA methyltransferase family (DNMT3)
DNMT3A (DNA Methyltransferase 3A) is a de novo DNA methyltransferase that plays critical roles in epigenetic regulation. It is involved in neuronal development and has been implicated in age-related cognitive decline and neurodegenerative diseases.
DNMT3A is a large de novo DNA methyltransferase comprising multiple functional domains:
- N-terminal regulatory domain: Contains the ADD (ATRX-DNMT3-DNMT3L) domain, which recognizes unmethylated histone H3 tails and mediates protein-protein interactions
- PWWP domain: Binds to H3K36me3-modified nucleosomes, targeting DNMT3A to gene bodies
- Bromo-adjacent homology (BAH) domain: Involved in chromatin recognition and regulatory functions
- C-terminal catalytic domain: Contains the methyltransferase active site with conserved motifs (I, IV, VI, IX, X)
The protein forms tetramers and interacts with various chromatin modifiers and transcription factors.
DNA methyltransferases are essential for establishing and maintaining DNA methylation patterns, which regulate gene expression without changing the DNA sequence. In the nervous system, DNMT3A plays critical roles:
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Epigenetic regulation of neurodevelopment: DNMT3A establishes new DNA methylation patterns during neuronal differentiation and brain development, particularly in prefrontal cortex and hippocampal neurons.
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Synaptic plasticity: DNMT3A-mediated DNA methylation regulates genes involved in synaptic formation, function, and plasticity, including NMDA receptor subunits and AMPA receptor components.
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Memory formation: Activity-dependent DNA methylation changes in the hippocampus require DNMT3A for long-term memory consolidation.
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Neuronal identity maintenance: DNMT3A helps maintain neuronal subtype identity by silencing alternative lineage programs through DNA methylation.
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Glial cell development: DNMT3A is essential for astrocyte and oligodendrocyte differentiation from neural progenitors.
DNMT3A dysfunction contributes to AD pathogenesis through several mechanisms:
- DNA methylation changes: Genome-wide hypomethylation and locus-specific hypermethylation are observed in AD brain. DNMT3A levels are reduced in AD neurons.
- Amyloid metabolism: DNMT3A regulates APP processing genes; methylation changes may increase Aβ production.
- Tau pathology: Methylation alterations affect tau kinases and phosphatases, potentially accelerating tau pathology.
- Neuronal dysfunction: Epigenetic dysregulation leads to altered expression of synaptic proteins and neuronal survival genes.
- SOD1 and C9orf72 regulation: DNMT3A contributes to epigenetic silencing of mutant SOD1 and dysregulated C9orf72 expression
- Motor neuron survival: Altered DNA methylation affects genes critical for motor neuron function
- Glial cell activation: DNMT3A in astrocytes may influence neuroinflammation
- alpha-synuclein methylation: SNCA methylation status affects α-synuclein expression
- Locus-specific changes: Hypermethylation of PARK16/IRX2 region associated with PD risk
¶ Rett Syndrome and Intellectual Disabilities
- DNMT3B and DNMT3A mutations: Cause ICF (immunodeficiency, centromeric instability, facial anomalies) syndrome with neurodegeneration
- MeCP2 interaction: Works with methyl-CpG binding proteins to regulate neuronal gene expression
- Epigenetic dysregulation: Altered DNMT3A expression and activity in ASD brain
- Synaptic gene methylation: Abnormal methylation of synaptic plasticity genes
| Approach |
Target/Mechanism |
Status |
| DNMT inhibitors (5-azacytidine, decitabine) |
Global DNA methylation modulation |
Preclinical |
| HDAC inhibitors |
Indirect DNMT modulation |
Clinical trials for cognitive disorders |
| Gene therapy |
Restoration of DNMT3A expression |
Research |
| Small molecule activators |
Enhance DNMT3A activity |
Discovery phase |
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Feng et al., DNMT3A in neural development and function (2020)
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Lin et al., DNA methylation in Alzheimer's disease (2022)
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Chestnut et al., Epigenetic regulation in ALS (2021)
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Jiang et al., DNMT3A and memory formation (2018)
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Morris et al., Epigenetic therapy for neurodegeneration (2023)
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Lv et al., DNMT3A mutations in neurodegenerative diseases (2022)
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Sanchez-Mut et al., DNA methylation signatures in AD (2016)
This page was created as part of the NeuroWiki protein page initiative for neurodegeneration research.
DNMT3A mutations are associated with several neurodegenerative and neurodevelopmental disorders:
- Tatton-Brown-Rahman Syndrome (TBRS): Caused by heterozygous DNMT3A mutations, characterized by intellectual disability, overgrowth, and distinctive facial features.
- Acquired DNMT3A mutations: Found in hematologic malignancies and associated with cognitive decline in some patients.
- Age-related DNA methylation changes: DNMT3A activity declines with age, potentially contributing to cognitive decline and neurodegenerative processes.
Targeting DNMT3A for neurodegeneration is complex due to its dual role in development and disease:
- Epigenetic therapies: DNMT inhibitors are being explored for various neurological conditions
- Gene therapy: Restoring proper DNMT3A expression patterns
- Understanding DNMT3A dynamics is critical for developing targeted interventions