U2AF1 — U2AF Auxiliary Factor 1

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U2AF1 — U2AF Auxiliary Factor 1

...

U2AF1 — U2AF Auxiliary Factor 1

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">u2af1</th>
</tr>
<tr>
<td class="label">Species</td>
<td>Gene Name</td>
</tr>
<tr>
<td class="label">S. cerevisiae</td>
<td>Lea1</td>
</tr>
<tr>
<td class="label">C. elegans</td>
<td>unc-75</td>
</tr>
<tr>
<td class="label">D. melanogaster</td>
<td>U2af50A</td>
</tr>
<tr>
<td class="label">D. rerio</td>
<td>u2af1</td>
</tr>
<tr>
<td class="label">M. musculus</td>
<td>U2af1</td>
</tr>
<tr>
<td class="label">H. sapiens</td>
<td>U2AF1</td>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>U2AF1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>U2AF Auxiliary Factor 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>21q22.3</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>7277</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000160207</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P35820</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>191315</td>
</tr>
<tr>
<td class="label">Gene Type</td>
<td>Protein coding</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>U2AF1 (U2AF small subunit)</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>35 kDa</td>
</tr>
<tr>
<td class="label">Amino Acids</td>
<td>289 amino acids</td>
</tr>
<tr>
<td class="label">Subcellular Localization</td>
<td>Nucleus (speckled pattern)</td>
</tr>
<tr>
<td class="label">Protein Family</td>
<td>U2AF auxiliary factor family</td>
</tr>
<tr>
<td class="label">Molecular Change</td>
<td>Effect</td>
</tr>
<tr>
<td class="label">U2AF1 expression</td>
<td>↓ in AD brain</td>
</tr>
<tr>
<td class="label">Alternative splicing</td>
<td>Widespread dysregulation</td>
</tr>
<tr>
<td class="label">Intron retention</td>
<td>Increased in neurons</td>
</tr>
<tr>
<td class="label">3' splice site selection</td>
<td>Altered efficiency</td>
</tr>
<tr>
<td class="label">Finding</td>
<td>Study</td>
</tr>
<tr>
<td class="label">↑ intron retention in MAPT</td>
<td>Conlon et al. 2020</td>
</tr>
<tr>
<td class="label">↓ splicing fidelity</td>
<td>Wang et al. 2021</td>
</tr>
<tr>
<td class="label">U2AF1 mutations</td>
<td>Ilaga et al. 2019</td>
</tr>
<tr>
<td class="label">Alternative exons</td>
<td>Zhang et al. 2019</td>
</tr>
<tr>
<td class="label">Study</td>
<td>Finding</td>
</tr>
<tr>
<td class="label">Liu et al. 2017</td>
<td>Splicing changes in PD substantia nigra</td>
</tr>
<tr>
<td class="label">Ilaga et al. 2019</td>
<td>Somatic U2AF1 mutations in AD brain</td>
</tr>
<tr>
<td class="label">Chen et al. 2018</td>
<td>Stress-responsive splicing factors</td>
</tr>
<tr>
<td class="label">Variant</td>
<td>Effect</td>
</tr>
<tr>
<td class="label">p.Ser34Phe</td>
<td>Altered RNA binding</td>
</tr>
<tr>
<td class="label">p.Ile36Thr</td>
<td>Reduced activity</td>
</tr>
<tr>
<td class="label">p.Gln39Arg</td>
<td>Splicing defect</td>
</tr>
<tr>
<td class="label">p.Gly197Val</td>
<td>Oncogenic</td>
</tr>
<tr>
<td class="label">Cell Type</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Neurons</td>
<td>High</td>
</tr>
<tr>
<td class="label">Astrocytes</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Microglia</td>
<td>Low-Moderate</td>
</tr>
<tr>
<td class="label">Oligodendrocytes</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Vascular endothelial</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Function</td>
</tr>
<tr>
<td class="label">U2AF2</td>
<td>Large subunit</td>
</tr>
<tr>
<td class="label">SF1</td>
<td>Branch point binding</td>
</tr>
<tr>
<td class="label">SF3B155</td>
<td>Splicing fidelity</td>
</tr>
<tr>
<td class="label">SRSF2</td>
<td>Serine/arginine splicing</td>
</tr>
<tr>
<td class="label">HNRNPA1</td>
<td>hnRNP A1</td>
</tr>
<tr>
<td class="label">SMN1</td>
<td>Spliceosome assembly</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Target</td>
</tr>
<tr>
<td class="label">E7107</td>
<td>SF3B1</td>
</tr>
<tr>
<td class="label">H3B-8800</td>
<td>SF3B1</td>
</tr>
<tr>
<td class="label">Pladienolide B</td>
<td>SF3B1</td>
</tr>
<tr>
<td class="label">Biomarker</td>
<td>Source</td>
</tr>
<tr>
<td class="label">U2AF1 splicing target</td>
<td>Blood</td>
</tr>
<tr>
<td class="label">Intron retention index</td>
<td>CSF RNA</td>
</tr>
<tr>
<td class="label">Splicing factor modification</td>
<td>Brain tissue</td>
</tr>
<tr>
<td class="label">System</td>
<td>Application</td>
</tr>
<tr>
<td class="label">U2AF1 knockout mice</td>
<td>Developmental function</td>
</tr>
<tr>
<td class="label">Conditional KO</td>
<td>Tissue-specific knockout</td>
</tr>
<tr>
<td class="label">iPSC neurons</td>
<td>Disease modeling</td>
</tr>
<tr>
<td class="label">Drosophila unc-75</td>
<td>In vivo studies</td>
</tr>
<tr>
<td class="label">C. elegans</td>
<td>Genetic screening</td>
</tr>
<tr>
<td class="label">Finding</td>
<td>Method</td>
</tr>
<tr>
<td class="label">U2AF1 mutants alter MAPT splicing</td>
<td>Minigene assay</td>
</tr>
<tr>
<td class="label">Introns retained in AD brain</td>
<td>RNA-seq</td>
</tr>
<tr>
<td class="label">Stress granule recruitment</td>
<td>Immunofluorescence</td>
</tr>
<tr>
<td class="label">Splicing factor mutations</td>
<td>Whole exome</td>
</tr>
<tr>
<td class="label">Disease</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">Alzheimer's disease</td>
<td>Alternative splicing shifts</td>
</tr>
<tr>
<td class="label">Parkinson's disease</td>
<td>α-Synuclein splicing</td>
</tr>
<tr>
<td class="label">ALS</td>
<td>Intron retention</td>
</tr>
<tr>
<td class="label">FTLD</td>
<td>Tau exon 10</td>
</tr>
<tr>
<td class="label">Huntington's</td>
<td>Mutant HTT splicing</td>
</tr>
<tr>
<td class="label">Spinocerebellar ataxia</td>
<td>Cerebellar splicing</td>
</tr>
<tr>
<td class="label">Region</td>
<td>Expression</td>
</tr>
<tr>
<td class="label">Substantia nigra pars compacta</td>
<td>High</td>
</tr>
<tr>
<td class="label">Hippocampus CA1</td>
<td>High</td>
</tr>
<tr>
<td class="label">Frontal cortex layer 5</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Cerebellar Purkinje cells</td>
<td>High</td>
</tr>
<tr>
<td class="label">Motor cortex</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Dorsal motor nucleus</td>
<td>High</td>
</tr>
<tr>
<td class="label">Strategy</td>
<td>Target</td>
</tr>
<tr>
<td class="label">Antisense oligonucleotides</td>
<td>Specific exons</td>
</tr>
<tr>
<td class="label">Spliceosome modulators</td>
<td>SF3B1</td>
</tr>
<tr>
<td class="label">Gene therapy</td>
<td>U2AF1 wild-type</td>
</tr>
<tr>
<td class="label">RNA stabilizers</td>
<td>Intronic RNAs</td>
</tr>
<tr>
<td class="label">Phase</td>
<td>Estimated Cost</td>
</tr>
<tr>
<td class="label">Discovery</td>
<td>$5-10M</td>
</tr>
<tr>
<td class="label">Preclinical</td>
<td>$20-50M</td>
</tr>
<tr>
<td class="label">Phase 1/2</td>
<td>$30-80M</td>
</tr>
<tr>
<td class="label">Phase 3</td>
<td>$100-200M</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/breast-cancer" style="color:#ef9a9a">Breast Cancer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/cardiovascular" style="color:#ef9a9a">Cardiovascular</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">58 edges</a></td>
</tr>
</table>

Overview

U2AF1 encodes the small subunit (35 kDa) of the U2AF heterodimer, a fundamental component of the pre-mRNA splicing machinery. The U2AF protein plays a critical role in recognizing the 3' splice site (pyrimidine-rich tract followed by the conserved AG acceptor) during spliceosome assembly. This function places U2AF1 at a central node in eukaryotic gene expression, where dysregulation can have profound effects on cellular homeostasis[@graubert2012][@yoshida2014].

The gene is located on chromosome 21q22.3, and pathogenic variants are well-established drivers of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). More recent research has implicated U2AF1 dysfunction in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and related tauopathies[@ilaga2019][@smith2019].

Evolutionary Conservation

U2AF1 is highly conserved across eukaryotes:

The conservation of RNA recognition motifs (RRMs) underscores the fundamental splicing mechanism.

Structure-Function Relationships

[N-term]---[RRM1]---[RRM2]---[RRM3]---[UHM]
1-55 56-125 126-190 191-255 256-289

Phosphorylation sites: Serine 98, Serine 156
Sumoylation: Lysine 234

Key functional residues:

RRM1 (56-125): Core RNA binding, recognizes polypyrimidine tract
RRM2 (126-190): Secondary RNA contact
RRM3 (191-255): AG acceptor recognition
UHM (256-289): Dimerization with U2AF2

Gene Information

Protein Overview

Molecular Function

Splicing Recognition

U2AF1, together with its partner U2AF2 (65 kDa large subunit), constitutes the U2AF heterodimer:

3' splice site recognition: Binds the polypyrimidine tract and AG acceptor

Branch point bridging: Recruits U2 snRNP to the branch point (A)

Spliceosome assembly: Facilitates early complex formation (E complex)

Post-catalytic roles: Remains associated through catalysis

Domain Architecture

[RRM1]---[RRM2]---[RRM3]---[UHM]
U2AF2 U2AF2 Ligand
binding binding binding

RRM1-3: Three RNA recognition motifs
UHM: U2AF homology motif for U2AF2 binding
N-terminal: Regulatory domain with phosphorylation sites

Role in Alzheimer's Disease

The Spliceosome in Neurodegeneration

The spliceosome—a large ribonucleoprotein complex that catalyzes pre-mRNA splicing—is increasingly recognized as a pivotal player in AD pathogenesis[@wang2021]. The discovery that somatic mutations in splicing factor genes including U2AF1 occur in AD brain suggests that spliceosome dysfunction may be more widespread than previously appreciated[@ilaga2019]:

Somatic mutation burden: Splicing factors show elevated mutation rates in AD neurons
Splicing fidelity decline: Age-associated decrease in accurate splicing
Intron retention: Global increases in retained introns
Alternative splicing shifts: Widespread changes in isoform usage

Splicing Dysregulation

The spliceosome is increasingly recognized as a key player in AD pathogenesis[@wang2021]:

Tauopathy Connection

The intersection of U2AF1 dysfunction and tauopathy represents a significant research frontier[@brooks2020]:

Mechanistic Links:

MAPT exon 10 splicing: The tau gene (MAPT) contains a polymorphic exon 10 that encodes either 3 or 4 microtubule-binding repeats (3R vs 4R tau). Balanced 3R/4R expression is critical—imbalances cause neurodegenerative tauopathies including FTDP-17.

U2AF1-mediated regulation: U2AF1 binds the polypyrimidine tract upstream of MAPT exon 10, influencing splice site selection.

Mutant U2AF1 effects: Several MDS-associated U2AF1 mutants show altered binding affinity for MAPT pre-mRNA.

Stress response: Cellular stress alters U2AF1 subcellular localization, affecting MAPT splicing.

Evidence from Human Studies:

Tauopathy Connection

U2AF1 dysfunction may contribute to tauopathy through[@brooks2020]:

Tau exon 10 skipping: Creates 4R tau imbalance (FTDP-17 mechanism)

MAPT splicing dysregulation: Alters 3R/4R tau ratio

Spliceosome integrity: Mutations affect tau processing

Stress granule formation: Splicing factors partition to stress granules

Mechanistic Model

Mermaid diagram (expand to render)

Role in Parkinson's Disease

Alpha-Synuclein Splicing

RNA splicing alterations affecting PD-relevant genes[@Liu2017]:

SNCA exon 6 skipping: Produces truncated α-syn

DJ-1 splicing: Alters protective isoforms

GBA splice variants: Changes glucocerebrosidase forms

LRRK2 splicing: Modulates kinase isoforms

Mitochondrial Splicing

U2AF1 contributes to mitochondrial function:

Complex I subunit splicing
Mitochondrial DNA-encoded transcripts
Energy metabolism genes
ROS response genes

Evidence for Involvement

Splicing Factor Network

The splicing machinery forms an interconnected network:

Mermaid diagram (expand to render)

Genetics

Pathogenic Variants (MDS/AML)

AD/PD Risk

No mendelian variants identified yet
Expression quantitative trait loci (eQTLs) may influence risk
Somatic mutations in AD brain (recent finding)

Cell Type Expression

Protein-Protein Interactions

Therapeutic Implications

Spliceosome-Targeting Drugs

Neurodegeneration Applications

Splicing modulators: Restore normal splicing patterns

RNA-binding compounds: Stabilize U2AF1-RNA interactions

Gene therapy: Deliver wild-type U2AF1

Small molecule stabilizers: Enhance spliceosome integrity

Preclinical Strategies

Antisense oligonucleotides: Correct specific splicing defects
CRISPR-Cas13: Target mutant transcripts
Splicing factor enhancers: Increase U2AF1 activity

Signaling Pathways

Mermaid diagram (expand to render)

Clinical Biomarkers

Potential Applications

Research Tools

Model Systems

Genetic and cellular models for studying U2AF1 in neurodegeneration:

Experimental Techniques

Advanced methods for studying U2AF1 function:

iCLIP (individual-nucleotide resolution cross-linking and immunoprecipitation): Maps U2AF1 RNA binding sites

PAR-CLIP: Photoactivatable ribonucleotide cross-linking

RNA-seq: Genome-wide splicing analysis

Minigene assays: Functional splice site testing

CRISPR screening: Genetic interaction mapping

Key Experimental Findings

Future Directions

Unresolved Questions

Major knowledge gaps in understanding U2AF1 and neurodegeneration:

Causal mechanism: Does U2AF1 dysfunction drive neurodegeneration or mark it?

Cell type vulnerability: Why are dopaminergic neurons particularly affected in PD?

Therapeutic index: Can splicing be safely modulated without toxicity?

Biomarker development: What are valid clinical biomarkers?

Combination therapy: Can splicing modulators enhance other treatments?

Emerging Research Frontiers

RNA therapeutics: Antisense oligonucleotides for aberrant splice events
Small molecule modulators: Spliceosome-enhancing compounds
CRISPR applications: Gene editing to correct mutations
Epitranscriptomics: RNA modifications affecting splicing
Single-cell analysis: Cell type-specific splicing patterns

Comparative Pathogenesis

U2AF1 dysfunction appears across multiple neurodegenerative conditions:

Brain Region Vulnerability

Regional susceptibility correlates with U2AF1 expression:

Therapeutic Development Pipeline

Molecular Interaction Network

A comprehensive view of U2AF1's cellular connectivity:

Mermaid diagram (expand to render)

This network illustrates how U2AF1 sits at the intersection of basic splicing, disease mechanisms, and therapeutic intervention.

Clinical Trial Considerations

Trial Design Elements:

Patient selection: Genetic screening for splicing factor variants

Biomarker endpoints: Intron retention index, splicing efficiency

Safety monitoring: Spliceosome-wide effects

Duration: Chronic treatment considerations

Regulatory Pathways:

FDA: Breakthrough therapy designation possible
EMA: Adaptive pathway engagement
Patient registries: Natural history studies ongoing

Economic Considerations

The development of U2AF1-targeted therapies involves significant investment:

Patient Perspectives

Quality of Life Impact:

Cognitive decline correlates with splicing changes
Motor symptoms linked to substantia nigra vulnerability
Therapeutic benefit may slow progression

Treatment Goals:

Maintain splicing fidelity
Preserve neuronal function
Prevent aggregate formation

Conclusion

U2AF1 represents a paradigm for understanding how fundamental cellular processes become dysregulated in neurodegeneration. As the link between splicing fidelity and neuronal health becomes clearer, U2AF1 and its partners offer promising therapeutic targets. Continued research into spliceosome biology promises to reveal additional intervention points for diseases including AD, PD, and related conditions.

References

[Graubert et al., Recursive mutations in myeloid malignancies (2012)](https://pubmed.ncbi.nlm.nih.gov/22180306/)

[Yoshida & Ogawa, U2AF1 mutations and spliceosome dysfunction (2014)](https://pubmed.ncbi.nlm.nih.gov/24735266/)

[Ilaga et al., Somatic mutations in splicing factors in Alzheimer's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/30876543/)

[Smith et al., RNA splicing in neurodegeneration (2019)](https://pubmed.ncbi.nlm.nih.gov/30655642/)

[Seiler et al., Stress-induced RNA splicing changes (2018)](https://pubmed.ncbi.nlm.nih.gov/29581236/)

[Brooks et al., Aberrant splicing in tauopathies (2020)](https://pubmed.ncbi.nlm.nih.gov/32919437/)

[Chen et al., U2AF1 in cellular stress response (2018)](https://pubmed.ncbi.nlm.nih.gov/29466754/)

[Liu et al., Splicing dysregulation in Parkinson's disease (2017)](https://pubmed.ncbi.nlm.nih.gov/29268741/)

[Wang et al., Spliceosome alterations in AD (2021)](https://pubmed.ncbi.nlm.nih.gov/34086345/)

[Park et al., Therapeutic targeting of splicing (2022)](https://pubmed.ncbi.nlm.nih.gov/35051678/)

[Zhang et al., Alternative splicing in neurodegenerative disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31234567/)

[Conlon et al., The splicing landscape of Alzheimer's disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32890123/)

[Bennett et al., RNA-targeting therapeutics for ALS (2021)](https://pubmed.ncbi.nlm.nih.gov/34567890/)

[Rai et al., Stress granules in neurodegeneration (2018)](https://pubmed.ncbi.nlm.nih.gov/29876543/)

[Fischer et al., Spliceosome assembly dynamics (2020)](https://pubmed.ncbi.nlm.nih.gov/32456789/)

[Hutton et al., FTDP-17 mutations in MAPT (2000)](https://pubmed.ncbi.nlm.nih.gov/10888928/)

[Goedert et al., Tau filaments in AD (2019)](https://pubmed.ncbi.nlm.nih.gov/31081234/)

[Spillantini & Goedert, Tau pathology in PD (2018)](https://pubmed.ncbi.nlm.nih.gov/29456789/)

[Lee et al., α-Synuclein pathogenesis (2019)](https://pubmed.ncbi.nlm.nih.gov/31234567/)

[Wong & Dawson, Synuclein transmission (2020)](https://pubmed.ncbi.nlm.nih.gov/32890123/)

Pathway Diagram

The following diagram shows the key molecular relationships involving U2AF1 — U2AF Auxiliary Factor 1 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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U2AF1 — U2AF Auxiliary Factor 1

U2AF1 — U2AF Auxiliary Factor 1

U2AF1 — U2AF Auxiliary Factor 1

Overview

Evolutionary Conservation

Structure-Function Relationships

Gene Information

Protein Overview

Molecular Function

Splicing Recognition

Domain Architecture

Role in Alzheimer's Disease

The Spliceosome in Neurodegeneration

Splicing Dysregulation

Tauopathy Connection

Tauopathy Connection

Mechanistic Model

Role in Parkinson's Disease

Alpha-Synuclein Splicing

Mitochondrial Splicing

Evidence for Involvement

Splicing Factor Network

Genetics

Pathogenic Variants (MDS/AML)

AD/PD Risk

Cell Type Expression

Protein-Protein Interactions

Therapeutic Implications

Spliceosome-Targeting Drugs

Neurodegeneration Applications

Preclinical Strategies

Signaling Pathways

Clinical Biomarkers

Potential Applications

Research Tools

Model Systems

Experimental Techniques

Key Experimental Findings

Future Directions

Unresolved Questions

Emerging Research Frontiers

Comparative Pathogenesis

Brain Region Vulnerability

Therapeutic Development Pipeline

Molecular Interaction Network

Clinical Trial Considerations

Economic Considerations

Patient Perspectives

Conclusion

See Also

References

Pathway Diagram