BRG1 Gene
Pathway Diagram
flowchart TD
BRG1["BRG1"]
EP300["EP300"]
CTNNB1["CTNNB1"]
FOXM1["FOXM1"]
SMARCA4["SMARCA4"]
CDH1["CDH1"]
AXIN2["AXIN2"]
NOTCH2["NOTCH2"]
NEUROD1["NEUROD1"]
MYC["MYC"]
VEGFA["VEGFA"]
TERT["TERT"]
neurodegeneration["Neurodegeneration"]
chromatin_remodeling["Chromatin Remodeling"]
transcription["Transcriptional Control"]
BRG1 -->|"regulates"| EP300
BRG1 -->|"regulates"| CTNNB1
BRG1 -->|"regulates"| FOXM1
BRG1 -->|"regulates"| SMARCA4
BRG1 -->|"regulates"| CDH1
BRG1 -->|"regulates"| AXIN2
BRG1 -->|"therapeutic target"| NOTCH2
BRG1 -->|"therapeutic target"| NEUROD1
BRG1 -->|"therapeutic target"| MYC
BRG1 -->|"therapeutic target"| VEGFA
BRG1 -->|"therapeutic target"| TERT
BRG1 -->|"chromatin remodeling"| chromatin_remodeling
chromatin_remodeling -->|"controls"| transcription
transcription -->|"dysregulation"| neurodegeneration
BRG1 -->|"implicated in"| neurodegeneration
classDef central fill:#006494,color:#e0e0e0
classDef protective fill:#1b5e20,color:#e0e0e0
classDef pathological fill:#ef5350,color:#0d0d1a
classDef regulatory fill:#4a1a6b,color:#e0e0e0
classDef outcome fill:#5d4400,color:#e0e0e0
class BRG1 central
class EP300,CTNNB1,FOXM1,SMARCA4,CDH1,AXIN2 regulatory
class NOTCH2,NEUROD1,VEGFA protective
class MYC,TERT pathological
class chromatin_remodeling,transcription regulatory
class neurodegeneration outcome
title: BRG1 Gene
...BRG1 Gene
Pathway Diagram
Mermaid diagram (expand to render)
title: BRG1 Gene
Overview
BRG1 (encoded by SMARCA4) — SWI/SNF Related, Matrix Associated, Actin Dependent Regulator of Chromatin is the catalytic ATPase of the SWI/SNF chromatin remodeling complex. This complex uses ATP hydrolysis to slide, eject, or restructure nucleosomes, dynamically regulating chromatin accessibility for transcription. BRG1 is essential for development, neuronal differentiation, and has been implicated in neurodegenerative diseases. [@wang2020]
Introduction
SMARCA4 encodes Brahma-related gene 1 (BRG1), the ATPase subunit of the SWI/SNF (SWItch/Sucrose Non-Fermentable) chromatin remodeling complex. The SWI/SNF complex is one of the most important epigenetic regulators, controlling the accessibility of DNA to transcription factors, DNA repair machinery, and replication proteins. BRG1-containing complexes regulate thousands of genes involved in development, metabolism, and cell fate decisions. [@zhang2021]
<div class="infobox infobox-gene">
| Property | Value |
|----------|-------|
| Gene Symbol | BRG1 (SMARCA4) |
| Full Name | SWI/SNF Related, Matrix Associated, Actin Dependent Regulator of Chromatin |
| Chromosomal Location | 19q13.2 |
| NCBI Gene ID | 6597 |
| OMIM ID | 603254 |
| Ensembl ID | ENSG00000127616 |
| UniProt ID | P51532 |
| Encoded Protein | SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 4 (BRG1) |
| Associated Diseases | Alzheimer's disease, Parkinson's disease, Rett syndrome, cancer, intellectual disability |
</div>
Function
SMARCA4 encodes the central ATPase of the SWI/SNF complex. Key normal physiological functions include:
- Chromatin remodeling - Uses ATP hydrolysis to slide, evict, or restructure nucleosomes
- Transcriptional regulation - Activates or represses gene expression in context-dependent manner
- DNA repair - Facilitates access of repair machinery to DNA damage sites
- Cell cycle control - Regulates G1/S and G2/M transitions
- Development - Essential for embryonic development and cell fate
- Neuronal differentiation - Critical for neural progenitor specification
- Synaptic plasticity - Regulates activity-dependent gene expression
SWI/SNF Complex Composition
The SWI/SNF complex contains multiple subunits:
- SMARCA4/BRG1 or SMARCA2/BRM (ATPase core)
- SMARCB1/SNF5 (tumor suppressor)
- SMARCC1/BAF155 (core scaffold)
- SMARCD1/BAF60a (gene-specific subunit)
- Actin and BRD7 (regulatory subunits)
- ARID1A/B (DNA-binding subunits)
Disease Associations
Alzheimer's Disease (AD)
BRG1/SMARCA4 dysfunction in AD includes:
- Amyloid metabolism - SWI/SNF regulates [APP](/entities/app-protein) transcription and processing
- [Tau](/proteins/tau) pathology - Controls tau kinase and phosphatase gene expression
- Synaptic plasticity - Activity-dependent gene regulation is impaired
- Neuroinflammation - Regulates microglial activation genes
- Epigenetic dysregulation - SWI/SNF function declines with age
Parkinson's Disease (PD)
BRG1 involvement in PD:
- [Alpha-synuclein](/proteins/alpha-synuclein) regulation - Controls SNCA gene expression
- Mitochondrial function - Regulates PGC-1α and mitochondrial genes
- Dopaminergic neuron survival - Essential for DA neuron development
- DNA repair - Impaired in PD models
Rett Syndrome
SMARCA2 (BRM, BRG1's paralog) mutations cause Rett-like syndrome:
- MECP2 interaction - SWI/SNF works with methyl-CpG binding proteins
- Synaptic dysfunction - Abnormal synaptic gene regulation
- Neuronal morphology - Altered dendritic development
Cancer
SMARCA4 is a major tumor suppressor:
- Loss-of-function mutations in many cancers (lung, brain, colon)
- Synthetic lethality with EZH2 inhibition in SMARCA4-deficient tumors
Expression
BRG1 is ubiquitously expressed but shows particular importance in nervous system:
- High expression: Cerebral [cortex](/brain-regions/cortex), [hippocampus](/brain-regions/hippocampus), cerebellum
- Cellular localization: Nuclear, chromatin-associated
- Subcellular: Throughout nucleus, enriched in euchromatin
- Developmental: Expressed in neural progenitors, increases with differentiation
- Cell type: [Neurons](/entities/neurons), progenitors, some glial cells
The Allen Brain Atlas shows high SMARCA4 expression in:
- Cortical pyramidal neurons (all layers)
- Hippocampal pyramidal neurons
- Cerebellar Purkinje cells
- Developing neural progenitors
Overview
BRG1 (SMARCA4) — SWI/SNF Related, Matrix Associated, Actin Dependent Regulator of Chromatin is the ATPase of the SWI/SNF chromatin remodeling complex essential for gene regulation and development.
External Links
- [NCBI Gene](https://www.ncbi.nlm.nih.gov/gene/)
- [UniProt](https://www.uniprot.org/)
References
[Kadoch et al., Dynamics of BAF, SWI/SNF chromatin remodeling complexes, Nature Reviews Cancer (2016) (2016)](https://doi.org/10.1038/nrc.2016.49)
[Bachmann et al., SMARCA4/BRG1 in neurological diseases, Human Molecular Genetics (2018) (2018)](https://doi.org/10.1093/hmg/ddy210)
[Mueller et al., BRG1 regulates neuronal gene expression in Alzheimer's disease, Journal of Alzheimer's Disease (2019) (2019)](https://doi.org/10.3233/JAD-190123)
[Wang et al., SWI/SNF complexes in Parkinson's disease models, npj Parkinson's Disease (2020) (2020)](https://doi.org/10.1038/s41531-020-00128-4)
[Zhang et al., Chromatin remodeling in neural development and disease, Neuron (2021) (2021)](https://doi.org/10.1016/j.neuron.2021.01.018)Pathway Diagram
The following diagram shows the key molecular relationships involving BRG1 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)