Ataxin-7 is a Transcriptional coactivator involved in retinal and neural gene expression. Associated with spinocerebellar ataxia type 7.
Atxn7 — Ataxin 7 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Property |
Value |
| Gene Symbol |
ATXN7 |
| Full Name |
Ataxin-7 |
| Chr Location |
3p12 |
| NCBI Gene ID |
6312 |
|
164655 |
| Ensembl ID |
ENSG00000104135 |
| UniProt ID |
O94905 |
| Encoded Protein |
Ataxin-7 |
| Associated Diseases |
Spinocerebellar ataxia type 7 (SCA7), macular degeneration |
ATXN7 encodes ataxin-7, a protein containing a polyglutamine (polyQ) tract. Like other SCA proteins, expansion of this polyQ tract causes neurodegeneration. Ataxin-7 is a component of the SPT3/SAGA complex, a transcriptional coactivator complex involved in histone acetylation.
Key normal physiological functions include:
- Transcriptional regulation - Component of SAGA/SLIK transcriptional coactivator complexes
- Histone acetylation - Facilitates chromatin remodeling through HAT activity
- DNA repair - Involved in transcription-coupled DNA repair pathways
- Photoreceptor function - Highly expressed in retinal photoreceptors
- Normal development - Essential for normal development and neuronal function
- Protein homeostasis - Involved in protein quality control pathways
The protein structure includes:
- N-terminal domain - Polyglutamine tract (pathological expansion)
- Central region - Protein interaction domains
- C-terminal domain - Nuclear localization signals
SCA7 is caused by CAG repeat expansion in ATXN7:
- Repeat expansion - >36 CAG repeats cause disease
- Age of onset - Typically 30-40 years, earlier with larger repeats
- Phenotype - Progressive ataxia, macular degeneration, visual loss
- Anticipation - Paternal transmission leads to earlier onset
- Neurodegeneration - Purkinje cell loss, retinal degeneration
- Mechanism - Toxic gain-of-function from polyQ-expanded protein
- ATXN7 variants associated with age-related macular degeneration
- Expressed in retinal pigment epithelium
- Links to photoreceptor function
- Inclusions found in other neurodegenerative conditions
- Altered expression in Alzheimer's and Parkinson's disease
Ataxin-7 is expressed in various tissues:
- Highest expression: Retina, cerebellum (Purkinje cells), cortex, heart
- Moderate expression: Most neural tissues
- Cellular localization: Nucleus, cytoplasm
- Cell types: Photoreceptors, neurons (especially Purkinje cells)
The Allen Brain Atlas shows high ATXN7 expression in:
- Cerebellar Purkinje cells
- Retinal photoreceptors
- Cortical pyramidal neurons
- Hippocampal neurons
- Holmes et al., SCA7 pathogenesis (2001)
- Helmlinger et al., Ataxin-7 in transcription (2004)
- Yvert et al., SCA7 and retinal degeneration (2000)
The study of Atxn7 — Ataxin 7 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.
- Pulst et al., SCA2 identification (1996)
- Elden et al., ATXN2 expansions in ALS (2010)
- Bhattacharjee et ATXN2 in RNA metabolism (2011)
- Last et al., Ataxin-2 function and disease (2020)
- Sato et al., ATXN2 in Parkinson's disease (2019)
- Gispert-Sanchez et al., ATXN2 and RNA granules (2015)
- Nonis et al., ATXN2 in diabetes (2022)
- Kumar et al., ATXN2 therapeutic targeting (2021)