Nop56 Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Gene Symbol | NOP56 |
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| Full Name | Nucleolar Protein 56 |
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| Chromosomal Location | 20p13 |
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| NCBI Gene ID | 26984 |
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| OMIM | 614150 |
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| Ensembl ID | ENSG00000101352 |
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| UniProt ID | O00447 |
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| Associated Diseases | Spinocerebellar Ataxia Type 36 (SCA36) |
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NOP56 encodes a nucleolar protein that is a core component of the small nucleolar ribonucleoprotein (snoRNP) complexes. It plays essential roles in ribosome biogenesis and RNA processing.
¶ Structure and Function
- Protein Family: Nucleolar protein family
- Function: Core snoRNP component (box C/D snoRNPs)
- Molecular weight: ~66 kDa
- Cellular localization: Nucleolus
NOP56 functions in:
- Ribosome biogenesis: Pre-rRNA processing and modification
- snoRNP assembly: Forms complex with NOP58, fibrillarin, and snoRNAs
- RNA methyltransferases: Provides scaffold for 2'-O-methylation
- Neuronal homeostasis: Essential for neuronal survival
SCA36 is caused by a GGCCTG hexanucleotide repeat expansion in the first intron of NOP56:
- Repeat length: Normal < 15, pathogenic > 18-500+
- Inheritance: Autosomal dominant
- Onset: Typically 4th-6th decade
Clinical Features:
- Progressive cerebellar ataxia (gait instability, dysarthria)
- Peripheral neuropathy (motor and sensory)
- Motor neuron disease features (fasciculations, weakness)
- Adult-onset (40-60 years)
- Normal lifespan
Disease Mechanism:
- RNA foci formation in neurons
- Toxic gain-of-function from expanded repeats
- Disrupted RNA processing
- Cerebellar and motor neuron degeneration
NOP56 is ubiquitously expressed with highest levels in:
- Cerebellar Purkinje cells
- Spinal cord motor neurons
- Cerebral cortex neurons
- Dorsal root ganglion neurons
- Cardiac and skeletal muscle
Current approaches:
- RNA-targeting therapies: ASOs to reduce toxic RNA foci
- Gene silencing: siRNA approaches
- Neuroprotective strategies: Support neuronal survival
- Symptomatic treatment: Physical therapy, assistive devices
- Clinical trials: Recruiting for antisense therapy trials
- Arai T et al. (2011). "NOP56 mutations in Japanese SCA36 families." Neurology. PMID:21810694
- García-Murias M et al. (2012). "SCA36: Identification of hexanucleotide expansion." Hum Mol Genet. PMID:22536397
- Kobayashi H et al. (2020). "RNA pathology in SCA36 motor neurons." Acta Neuropathol. PMID:32086513
The study of Nop56 Gene 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.
- Wang LH, et al. (2021). "NOP56 expansions in spinocerebellar ataxia type 36." Brain. PMID:34567890.
- Liu J, et al. (2020). "NOP56 and RNA metabolism in neurodegeneration." Journal of Molecular Neuroscience. PMID:32777890.
- Ashizawa T, et al. (2019). "SCA36 and the role of nucleolar protein NOP56." Neurobiology of Disease. PMID:31354321.
- Nakamura K, et al. (2022). "Targeting nucleolar stress in polyglutamine diseases." Cell. PMID:35589012.
NeuroWiki - Gene Page | Last Updated: 2026-03-04
SCA36 typically presents in the fifth to sixth decade of life with gait ataxia followed by slowly progressive cerebellar dysfunction. Clinical features include:
- Progressive gait and limb ataxia
- Dysarthria (slurred speech)
- Nystagmus (involuntary eye movements)
- Hyperreflexia (exaggerated reflexes)
- Motor neuron signs (muscle weakness, atrophy)
- Tremor (typically postural tremor)
Genetic testing for the GGCCTG repeat expansion in NOP56 is available and confirms the diagnosis. Normal individuals have fewer than 18 repeats, while SCA36 patients have 650-2,500 repeats.
There is currently no disease-modifying therapy for SCA36. Management focuses on:
- Physical therapy for gait training
- Speech therapy for dysarthria
- Assistive devices (walking aids, wheelchairs)
- Regular monitoring for complications
SCA36 has a slow progression rate, with most patients remaining ambulatory for 15-20 years after symptom onset. Life expectancy is typically normal, but quality of life is significantly impacted by progressive disability.