BACH1 — BTB Domain and CNC Homolog 1

BACH1 — BTB Domain and CNC Homolog 1

<table class="infobox infobox-gene">
<tr><th class="infobox-header" colspan="2">BACH1 — BTB Domain and CNC Homolog 1</th></tr>
<tr><td class="label">Symbol</td><td><strong>BACH1</strong></td></tr>
<tr><td class="label">Full Name</td><td>BTB Domain and CNC Homolog 1</td></tr>
<tr><td class="label">Chromosome</td><td>21q21.3</td></tr> [@sunuwar2023]
<tr><td class="label">NCBI Gene</td><td><a href="https://www.ncbi.nlm.nih.gov/gene/571" target="_blank">571</a></td></tr> [@casares2024]
<tr><td class="label">Ensembl</td><td><a href="https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000156273" target="_blank">ENSG00000156273</a></td></tr>
<tr><td class="label">OMIM</td><td><a href="https://omim.org/entry/602751" target="_blank">602751</a></td></tr>
<tr><td class="label">UniProt</td><td><a href="https://www.uniprot.org/uniprot/O14867" target="_blank">O14867</a></td></tr>
<tr><td class="label">Diseases</td><td>[Alzheimer's Disease](/diseases/alzheimers), [Parkinson's Disease](/diseases/parkinsons-disease), [ALS](/diseases/als)</td></tr>
<tr><td class="label">Expression</td><td>Ubiquitous, high in brain, liver, spleen</td></tr>
<tr><th class="infobox-subheader" colspan="2">Key Features</th></tr>
<tr><td colspan="2" style="font-size:0.85em">Transcriptional repressor competing with NRF2<br>Heme-sensing transcription factor<br>Regulates oxidative stress response genes</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="co

BACH1 — BTB Domain and CNC Homolog 1

<table class="infobox infobox-gene">
<tr><th class="infobox-header" colspan="2">BACH1 — BTB Domain and CNC Homolog 1</th></tr>
<tr><td class="label">Symbol</td><td><strong>BACH1</strong></td></tr>
<tr><td class="label">Full Name</td><td>BTB Domain and CNC Homolog 1</td></tr>
<tr><td class="label">Chromosome</td><td>21q21.3</td></tr> [@sunuwar2023]
<tr><td class="label">NCBI Gene</td><td><a href="https://www.ncbi.nlm.nih.gov/gene/571" target="_blank">571</a></td></tr> [@casares2024]
<tr><td class="label">Ensembl</td><td><a href="https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000156273" target="_blank">ENSG00000156273</a></td></tr>
<tr><td class="label">OMIM</td><td><a href="https://omim.org/entry/602751" target="_blank">602751</a></td></tr>
<tr><td class="label">UniProt</td><td><a href="https://www.uniprot.org/uniprot/O14867" target="_blank">O14867</a></td></tr>
<tr><td class="label">Diseases</td><td>[Alzheimer's Disease](/diseases/alzheimers), [Parkinson's Disease](/diseases/parkinsons-disease), [ALS](/diseases/als)</td></tr>
<tr><td class="label">Expression</td><td>Ubiquitous, high in brain, liver, spleen</td></tr>
<tr><th class="infobox-subheader" colspan="2">Key Features</th></tr>
<tr><td colspan="2" style="font-size:0.85em">Transcriptional repressor competing with NRF2<br>Heme-sensing transcription factor<br>Regulates oxidative stress response genes</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">140 edges</a></td>
</tr>
</table>

Overview

BACH1 (BTB Domain and CNC Homolog 1) encodes a transcriptional repressor that competes with [NRF2](/genes/nfe2l2) for binding to antioxidant response elements (AREs) in the promoters of cytoprotective genes. BACH1 acts as a heme sensor — when intracellular heme levels rise (as occurs during oxidative stress or hemolysis), heme binds to BACH1's cysteine-proline (CP) motifs, triggering its nuclear export and proteasomal degradation. This derepression allows NRF2 to activate target genes including [HMOX1](/genes/hmox1) (heme oxygenase-1), [NQO1](/genes/nqo1), and glutathione synthesis enzymes.

In neurodegenerative diseases, the BACH1-NRF2 axis is a critical determinant of cellular resilience to oxidative stress. BACH1 inhibition represents an emerging therapeutic strategy for enhancing neuroprotective antioxidant responses in [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and [ALS](/diseases/als).

The protein encoded by BACH1 is [BACH1 Protein](/proteins/bach1-protein). See the protein page for detailed structural and functional information.

Function

Transcriptional Repression

BACH1 functions as a cap'n'collar (CNC) family transcription factor that:

• Heterodimerizes with small Maf proteins (MafF, MafG, MafK) to bind Maf recognition elements (MAREs) and AREs
• Competes with NRF2 for ARE binding, acting as a constitutive repressor of antioxidant gene expression under basal conditions
• Represses HMOX1: The [HMOX1](/genes/hmox1) promoter contains multiple AREs that are occupied by BACH1-Maf heterodimers in the absence of stress
• Regulates iron metabolism: Controls ferritin heavy chain (FTH1) and ferroportin (SLC40A1) expression

Heme-Dependent Regulation

BACH1 contains six CP motifs that serve as heme-binding sites:

NRF2-BACH1 Switching Model

Disease Associations

Alzheimer's Disease

BACH1 dysregulation contributes to oxidative damage in [AD](/diseases/alzheimers-disease):

• BACH1 protein levels are elevated in AD [hippocampus](/brain-regions/hippocampus), correlating with reduced HMOX1 expression
• [Amyloid-beta](/proteins/amyloid-beta) induces oxidative stress but fails to adequately degrade BACH1 in aged [neurons](/entities/neurons)
• BACH1 knockout mice show enhanced HMOX1 expression and resistance to amyloid-beta-induced oxidative damage
• The BACH1 gene is located on chromosome 21, raising the possibility of gene dosage effects in Down syndrome-associated AD

Parkinson's Disease

In [PD](/diseases/parkinsons-disease), BACH1 opposes neuroprotective NRF2 signaling:

• Dopaminergic neurons in the substantia nigra have high oxidative burden due to dopamine metabolism
• BACH1 repression of HMOX1 limits the ability of these neurons to cope with iron-mediated oxidative stress
• BACH1 inhibition enhances NRF2-dependent protection of dopaminergic neurons in MPTP models
• [Alpha-synuclein](/proteins/alpha-synuclein) aggregation impairs the KEAP1-NRF2 pathway, making BACH1 derepression critical

ALS

• Motor neurons show vulnerability to oxidative stress, partly mediated by BACH1 repression of antioxidant genes
• [SOD1](/entities/sod1) mutant models show altered BACH1-NRF2 balance
• BACH1 inhibition is being explored as a strategy to enhance motor neuron resilience

Therapeutic Targeting

BACH1 inhibitors are in development for neurodegenerative diseases:

• HMOX1 inducers: Compounds that promote BACH1 degradation and HMOX1 derepression
• Direct BACH1 inhibitors: Small molecules blocking BACH1-DNA interaction
• Heme mimetics: Synthetic compounds that bind BACH1 CP motifs, triggering its degradation

Expression

BACH1 is ubiquitously expressed with notable levels in:

• Brain: Cortical neurons, hippocampal neurons, substantia nigra dopaminergic neurons
• Liver: Hepatocytes (major site of heme metabolism)
• Spleen: Macrophages involved in erythrocyte clearance
• Bone marrow: Erythroid precursors
• Immune cells: Monocytes and macrophages (including [microglia](/cell-types/microglia))

See Also

• [NFE2L2 (NRF2)](/genes/nfe2l2) — Competing transcription factor at AREs
• [KEAP1](/genes/keap1) — NRF2 negative regulator
• [HMOX1](/genes/hmox1) — Major BACH1 target gene
• [Oxidative Stress in Neurodegeneration](/mechanisms/oxidative-stress) — Central pathogenic mechanism
• [NQO1](/genes/nqo1) — Cytoprotective NRF2 target

External Links

• [NCBI Gene: BACH1](https://www.ncbi.nlm.nih.gov/gene/571)
• [UniProt: O14867](https://www.uniprot.org/uniprot/O14867)
• [GeneCards: BACH1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=BACH1)
• [OMIM: 602751](https://omim.org/entry/602751)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving BACH1 — BTB Domain and CNC Homolog 1 discovered through SciDEX knowledge graph analysis: