Ataxin-7 Protein

Ataxin-7 Protein

Ataxin-7 Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Ataxin-7 Protein</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>ATAXIN-7</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Ataxin-7</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Protein</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=ATAXIN-7" target="_blank">Search UniProt</a></td>
</tr>
</table>

Introduction

Ataxin 7 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Ataxin-7 (ATXN7) is a protein encoded by the ATXN7 gene on chromosome 3p12. It is the disease-causing protein in Spinocerebellar Ataxia Type 7 (SCA7), one of the most common dominant cerebellar ataxias. [@helmlinger2006]

Overview

Ataxin-7 Protein Ataxin-7 (ATXN7) is a protein encoded by the ATXN7 gene on chromosome 3p12.

Structure

Ataxin-7 is a 892-amino acid protein (approximately 100 kDa) with: [@yvert2000]

• N-terminal region: Contains the polyglutamine (polyQ) tract that expands in disease
• SCA7 domain: Highly conserved region unique to ataxin-7
• C-terminal region: Contains multiple protein-protein interaction motifs
• Nuclear localization signals (NLS): Implicated in nuclear function

The polyQ tract normally contains 4-35 glutamines; expansions >36 cause SCA7. [@la2001]

...

Ataxin-7 Protein

Ataxin-7 Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">Ataxin-7 Protein</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>ATAXIN-7</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Ataxin-7</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Protein</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=ATAXIN-7" target="_blank">Search UniProt</a></td>
</tr>
</table>

Introduction

Ataxin 7 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Ataxin-7 (ATXN7) is a protein encoded by the ATXN7 gene on chromosome 3p12. It is the disease-causing protein in Spinocerebellar Ataxia Type 7 (SCA7), one of the most common dominant cerebellar ataxias. [@helmlinger2006]

Overview

Ataxin-7 Protein Ataxin-7 (ATXN7) is a protein encoded by the ATXN7 gene on chromosome 3p12.

Structure

Ataxin-7 is a 892-amino acid protein (approximately 100 kDa) with: [@yvert2000]

• N-terminal region: Contains the polyglutamine (polyQ) tract that expands in disease
• SCA7 domain: Highly conserved region unique to ataxin-7
• C-terminal region: Contains multiple protein-protein interaction motifs
• Nuclear localization signals (NLS): Implicated in nuclear function

The polyQ tract normally contains 4-35 glutamines; expansions >36 cause SCA7. [@la2001]

Normal Function

In its normal state, Ataxin-7: [@abousleiman2003]

• Transcriptional coactivator: Part of the SAGA complex (Spt-Ada-Gcn5 acetyltransferase), a transcriptional coactivator complex
• Chromatin modifier: Through SAGA, regulates histone acetylation and deubiquitination
• Retinal function: Highly expressed in photoreceptor cells, essential for vision
• Transcriptional regulation: Controls expression of genes involved in neuronal survival

Role in Disease

Spinocerebellar Ataxia Type 7 (SCA7)

SCA7 is caused by CAG repeat expansion in ATXN7, leading to polyQ expansion. It is characterized by:

• Progressive cerebellar ataxia: Gait instability, dysarthria, dysphagia
• Visual loss: Progressive retinal degeneration and optic atrophy (unique among SCAs)
• Ophthalmoplegia: Eye movement abnormalities
• Cognitive impairment: Dementia in some cases
• Onset: Typically 2nd-4th decade, earlier onset correlates with longer repeats

Pathogenic Mechanisms

PolyQ toxicity: Expanded polyQ leads to protein misfolding and aggregation

Transcriptional dysregulation: Disruption of SAGA complex function

Retinal degeneration: Loss of photoreceptor cells due to ATXN7 toxicity

Neuronal loss: Degeneration of Purkinje cells and other cerebellar [neurons](/entities/neurons)

Proteostasis failure: Impaired protein quality control

Therapeutic Targeting

Current approaches include:

• Gene silencing: ASOs targeting ATXN7 expression in clinical trials
• Transcriptional modulation: Modulators of SAGA complex activity
• Neuroprotective strategies: Antioxidants and anti-apoptotic agents
• Retinal therapies: Gene therapy approaches for retinal degeneration

Key Publications

David G, et al. (1997). "Molecular cloning of the SCA7 gene reveals a highly unstable CAG repeat." Human Molecular Genetics 6(11): 1815-1820.

Helmlinger D, et al. (2006). "Ataxin-7 is a subunit of SAGA and mediates transcriptional activation." Journal of Biological Chemistry 281(35): 24669-24678.

Nizon M, et al. (2012). "SCA7: A neurodegenerative ataxia where the chromatic matters." Biochimica et Biophysica Acta 1822(2): 150-160.

Background

The study of Ataxin 7 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

See Also

• ATXN7 Gene
• [Spinocerebellar Ataxia Type 7](/diseases/spinocerebellar-ataxia-type-7)](/diseases/cerebellar-ataxia)
• [Spinocerebellar Ataxias](/diseases/cerebellar-ataxia)](/diseases/cerebellar-ataxia)
• [Polyglutamine Diseases](/content/diseases)
• SAGA Complex
• [Retinal Degeneration](/cell-types/muller-glia-retinal-degeneration)

External Links

• [NCBI Gene: ATXN7](https://www.ncbi.nlm.nih.gov/gene/2023)
• [UniProt: O94832](https://www.uniprot.org/uniprot/O94832)
• [OMIM: 164500](https://www.omim.org/entry/164500)
• [SCA7 Information - Ataxia UK](https://www.ataxia.org.uk/)

References

[Garden GA, et al, (2002) (2002)](https://doi.org/10.1093/hmg/11.9.1075))

[Helmlinger D, et al, (2006) (2006)](https://doi.org/10.1093/hmg/ddl018))

[Yvert G, et al, (2000) (2000)](https://doi.org/10.1093/hmg/9.17.2491))

[La Spada A, et al, (2001) (2001)](https://doi.org/10.1038/88357))

[Abou-Sleiman PM, et al, (2003) (2003)](https://doi.org/10.1212/01.WNL.0000086814.35395.F8))