NEIL1 Protein — Nei Endonuclease VIII-Like 1

NEIL1 Protein — Nei Endonuclease VIII-Like 1

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">NEIL1 Protein — Nei Endonuclease VIII-Like 1</th>
</tr>
<tr>
<td class="label">Lesion</td>
<td>Type</td>
</tr>
<tr>
<td class="label">8-oxoguanine (8-oxoG)</td>
<td>Purine</td>
</tr>
<tr>
<td class="label">5-hydroxyuracil</td>
<td>Pyrimidine</td>
</tr>
<tr>
<td class="label">Thymine glycol</td>
<td>Pyrimidine</td>
</tr>
<tr>
<td class="label">FapyGuanine</td>
<td>Purine</td>
</tr>
<tr>
<td class="label">5-hydroxycytosine</td>
<td>Pyrimidine</td>
</tr>
<tr>
<td class="label">8-oxoadenine</td>
<td>Purine</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/carcinoma" style="color:#ef9a9a">Carcinoma</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/senescence" style="color:#ef9a9a">Senescence</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">30 edges</a></td>
</tr>
</table>

Introduction

NEIL1 Protein — Nei Endonuclease VIII-Like 1

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">NEIL1 Protein — Nei Endonuclease VIII-Like 1</th>
</tr>
<tr>
<td class="label">Lesion</td>
<td>Type</td>
</tr>
<tr>
<td class="label">8-oxoguanine (8-oxoG)</td>
<td>Purine</td>
</tr>
<tr>
<td class="label">5-hydroxyuracil</td>
<td>Pyrimidine</td>
</tr>
<tr>
<td class="label">Thymine glycol</td>
<td>Pyrimidine</td>
</tr>
<tr>
<td class="label">FapyGuanine</td>
<td>Purine</td>
</tr>
<tr>
<td class="label">5-hydroxycytosine</td>
<td>Pyrimidine</td>
</tr>
<tr>
<td class="label">8-oxoadenine</td>
<td>Purine</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/carcinoma" style="color:#ef9a9a">Carcinoma</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/senescence" style="color:#ef9a9a">Senescence</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">30 edges</a></td>
</tr>
</table>

Introduction

NEIL1 (Nei Endonuclease VIII-Like 1) is a DNA glycosylase that initiates the base excision repair (BER) pathway by recognizing and removing oxidized base lesions from DNA. As a member of the Fpg/Nei family of DNA glycosylases, NEIL1 plays a critical role in maintaining genomic integrity by repairing oxidative DNA damage that accumulates from normal cellular metabolism and environmental exposures. This protein is essential for protecting both nuclear and mitochondrial DNA, and its dysfunction has been implicated in neurodegenerative diseases including Alzheimer's disease and Parkinson's disease, as well as in cancer development [@hegde2020].

Overview

NEIL1 is a 44.6 kDa protein encoded by the NEIL1 gene located on chromosome 15q24.2. It contains 406 amino acids and is expressed in various tissues, with high expression in the brain, liver, and testis. Unlike other DNA glycosylases, NEIL1 has a unique C-terminal mitochondrial targeting sequence that directs it to both the nucleus and mitochondria, allowing it to protect both genomes from oxidative damage.

The enzyme is particularly important in neurons, which have high metabolic rates and are exposed to significant oxidative stress. NEIL1's ability to recognize and repair a broad spectrum of oxidized purine and pyrimidine bases makes it a crucial defender against the accumulation of DNA damage that can lead to neurodegeneration [@chan2022].

Structure

NEIL1 possesses a characteristic Fpg/Nei family domain architecture:

Domain Organization

• Catalytic Domain (residues 1-300): Contains the DNA glycosylase active site
• Zinc Finger Domain (residues 80-120): Facilitates DNA binding through a zinc finger motif
• Helix-hairpin-helix (HhH) motif: Common DNA binding structure in glycosylases
• C-terminal Domain (residues 301-406): Substrate recognition and mitochondrial targeting

Structural Features

The protein contains several key structural elements:

• Catalytic Residue: Asp⁷⁵ acts as the nucleophile that cleaves the glycosidic bond
• Base Flipping Mechanism: The enzyme extrudes damaged bases from the DNA helix for inspection
• Zinc Finger: Stabilizes DNA binding and lesion recognition
• Mitochondrial Targeting Sequence: C-terminal signal that directs protein to mitochondria

Active Site Architecture

The active site of NEIL1 is optimized for recognizing and processing oxidized bases:

• Lesion Recognition Pocket: Specifically shaped for oxidized purines and pyrimidines
• Catalytic Center: Contains the essential Asp residue for nucleophilic attack
• DNA Backbone Contacts: Interacts with the phosphate backbone to position the substrate

Normal Function

NEIL1 performs essential DNA repair functions in both the nucleus and mitochondria:

Substrate Specificity

NEIL1 recognizes and removes a wide range of oxidized DNA bases:

Base Excision Repair Mechanism

NEIL1 initiates the BER pathway through a stepwise process:

Biological Functions

• Nuclear DNA Repair: Maintains genomic integrity in the nucleus
• Mitochondrial DNA Repair: Protects mtDNA from oxidative damage [@morrish2020]
• Cell Cycle Regulation: Couples DNA repair to cell cycle progression
• Genomic Stability: Prevents mutations from accumulating
• Neuroprotection: Protects neurons from oxidative stress-induced death

Role in Disease

Alzheimer's Disease

NEIL1 expression and activity are reduced in Alzheimer's disease brain [@bochkareva2018]:

• Epigenetic silencing: NEIL1 promoter hypermethylation reduces expression
• BER impairment: Accumulation of 8-oxoG and other lesions
• DNA damage accumulation: Triggers neuronal apoptosis
• Therapeutic potential: BER pathway enhancers may benefit AD patients

Parkinson's Disease

NEIL1 dysfunction contributes to PD pathology [@kelley2019]:

• Mitochondrial vulnerability: Dopaminergic neurons are particularly sensitive to mtDNA damage
• Altered activity: Reduced NEIL1 function in PD models
• Dopaminergic neuron loss: Accumulated DNA damage contributes to cell death
• α-Synuclein interaction: Possible connection to PD pathology

Amyotrophic Lateral Sclerosis (ALS)

• Motor neuron sensitivity: Motor neurons accumulate DNA damage
• BER deficiency: Impaired repair mechanisms in ALS
• Therapeutic target: DNA repair enhancement strategies

Cancer

NEIL1 functions as a tumor suppressor:

• Polymorphisms: Certain NEIL1 variants increase cancer risk
• Epigenetic silencing: Promoter hypermethylation in various cancers
• Genomic instability: Loss of NEIL1 leads to increased mutations
• Therapeutic targeting: NEIL1 expression affects chemosensitivity

Therapeutic Implications

Targeting NEIL1 offers therapeutic opportunities:

Key Publications

Cross-links

• [NEIL1 Gene](/genes/neil1)
• [OGG1 Protein](/proteins/ogg1-protein)
• [DNA Repair](/mechanisms/dna-repair)
• [Base Excision Repair](/mechanisms/base-excision-repair)
• [Alzheimer's Disease](/diseases/alzheimers)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Mitochondrial DNA](/mechanisms/mitochondrial-dna)
• [Oxidative Stress](/mechanisms/oxidative-stress)

External Links

• [UniProt - NEIL1 (Q9Y3X0)](https://www.uniprot.org/uniprot/Q9Y3X0)
• [GeneCards - NEIL1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=NEIL1)
• [PDB - 1TDH](https://www.rcsb.org/structure/1TDH)
• [Human Protein Atlas - NEIL1](https://www.proteinatlas.org/ENSG00000140323-NEIL1)
• [PubMed - NEIL1 Research](https://pubmed.ncbi.nlm.nih.gov/?term=NEIL1+DNA+glycosylase)

References