GO:0031120 snRNA pseudouridine synthesis: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031120 (snRNA pseudouridine synthesis) describes the intramolecular conversion of uridine to pseudouridine (Ψ) within small nuclear RNA (snRNA) molecules.
• Pseudouridine synthases (PUS enzymes) catalyze this isomerization without cofactors, using a conserved catalytic aspartate.
• Pseudouridylation of snRNAs is guided by box H/ACA snoRNPs and occurs in Cajal bodies, influencing spliceosome assembly and function.
• The modification is essential for snRNA stability, pre-mRNA splicing, and proper gene expression.
• Dysregulation of snRNA pseudouridylation is linked to cancer, viral replication, and developmental disorders.
• Studying GO:0031120 requires base-resolution Ψ mapping, CRISPR knockout models, and functional splicing assays.
Description
Pseudouridine (Ψ) is the most abundant post-transcriptional RNA modification, and its synthesis in small nuclear RNAs (snRNAs) is a critical step in RNA maturation. GO:0031120, snRNA pseudouridine synthesis, refers specifically to the intramolecular conversion of uridine to pseudouridine within snRNA molecules. This process is catalyzed by pseudouridine synthases, often guided by box H/ACA small nucleolar RNPs (snoRNPs), and occurs predominantly in Cajal bodies. snRNA pseudouridylation enhances the structural stability and function of the spliceosome, thereby influencing pre-mRNA splicing and gene expression. Researchers study GO:0031120 to understand how RNA modifications contribute to transcriptome diversity and cellular regulation. Recent advances in absolute quantitative, base-resolution sequencing have revealed comprehensive landscapes of pseudouridine across the human transcriptome, including snRNAs. Dysregulation of this process has been implicated in cancer, viral infections, and neurological disorders. Thus, snRNA pseudouridine synthesis represents a key node linking RNA modification to human health and disease.
snRNA pseudouridine synthesis At A Glance
| GO ID | GO:0031120 |
|---|---|
| GO term | snRNA pseudouridine synthesis |
| Ontology | biological_process |
| Synonym | None |
| Major function | Conversion of uridine to pseudouridine in snRNA |
| Catalytic mechanism | Isomerization by pseudouridine synthases (PUS enzymes) |
| Guiding factors | Box H/ACA snoRNPs |
| Subcellular location | Cajal bodies, nucleoplasm |
| Related processes | Pre-mRNA splicing, spliceosome assembly |
What Is GO:0031120?
GO:0031120, snRNA pseudouridine synthesis, is defined as the intramolecular conversion of uridine to pseudouridine in an snRNA molecule. This enzymatic isomerization does not require ATP or other cofactors and is catalyzed by pseudouridine synthases, which cleave the glycosidic bond, rotate the uracil base, and reattach it via a carbon-carbon bond. The modification occurs post-transcriptionally and is often directed by box H/ACA snoRNAs that base-pair with target uridines.
Why Is snRNA pseudouridine synthesis Important in Cell Biology?
snRNA pseudouridine synthesis is essential for the proper function of the spliceosome, the machinery that removes introns from pre-mRNA. Pseudouridylation enhances snRNA stability and RNA-protein interactions, thereby affecting splicing fidelity and gene expression. Aberrant pseudouridylation has been linked to cancer progression, viral replication, and developmental disorders. Understanding GO:0031120 provides insights into RNA modification biology and offers potential therapeutic targets.
• Enhances snRNA structural stability and spliceosome assembly.
• Modulates pre-mRNA splicing and gene expression.
• Required for efficient viral replication, as shown for KSHV.
• Dysregulated in cancers, including those with PUS7 mutations.
• Involved in 7SK snRNA pseudouridylation regulating Pol II transcription elongation.
• Guided by box H/ACA snoRNPs, linking snoRNA function to snRNA modification.
• Provides a mechanism for dynamic RNA modification in response to cellular signals.
• Offers targets for therapeutic intervention in splicing-related diseases.
• Enables base-resolution mapping of Ψ to study transcriptome-wide changes.
• Connects RNA modification to Cajal body biology and nuclear organization.
What Happens During snRNA pseudouridine synthesis?
Recognition of target uridine by box H/ACA snoRNPs
In simple terms: A guide RNA finds the exact uridine to modify.
Box H/ACA snoRNPs contain a guide RNA that base-pairs with the target snRNA, positioning the uridine for modification. This recognition is sequence-specific and ensures that pseudouridylation occurs at precise sites.
Catalytic isomerization by pseudouridine synthases
In simple terms: The enzyme flips the RNA base to create pseudouridine.
Pseudouridine synthases (PUS enzymes) catalyze the isomerization of uridine to pseudouridine through a conserved aspartate residue, without cofactors. The reaction involves cleavage of the glycosidic bond, rotation of the uracil ring, and reattachment via a carbon-carbon bond.
Occurrence in Cajal bodies
In simple terms: The modification happens in specific nuclear compartments.
snRNA pseudouridylation predominantly occurs in Cajal bodies, where box H/ACA snoRNPs and pseudouridine synthases are concentrated. This subnuclear localization facilitates efficient modification and assembly of snRNPs.
Impact on spliceosome function
In simple terms: The modified RNA works better in the splicing machine.
Pseudouridylation enhances snRNA stability and RNA-protein interactions, promoting spliceosome assembly and pre-mRNA splicing. Loss of pseudouridylation can impair splicing fidelity and gene expression.
Key Genes Involved in GO:0031120 snRNA pseudouridine synthesis
The following genes and proteins are central to snRNA pseudouridine synthesis, including pseudouridine synthases and box H/ACA snoRNP components.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PUS1 | Pseudouridine synthase | Catalyzes Ψ formation in snRNA and tRNA |
| PUS7 | Pseudouridine synthase | Modifies 7SK snRNA, regulates Pol II elongation |
| DKC1 | Dyskerin, box H/ACA snoRNP component | Guides pseudouridylation, mutated in dyskeratosis congenita |
| NHP2 | Box H/ACA snoRNP protein | Essential for snoRNP stability and function |
| NOP10 | Box H/ACA snoRNP protein | Required for pseudouridylation activity |
| GAR1 | Box H/ACA snoRNP protein | Binds guide RNA, facilitates modification |
| SNRPA | U1 snRNP component | Target of pseudouridylation, affects splicing |
| SNRPB | U2 snRNP component | Pseudouridylation impacts spliceosome assembly |
| SNRPD1 | Core snRNP protein | Modification influences snRNP function |
| SNRPE | Core snRNP protein | Pseudouridylation affects snRNP stability |
| SNRPF | Core snRNP protein | Involved in snRNP assembly |
| SNRPG | Core snRNP protein | Pseudouridylation modulates interactions |
| PRPF8 | Spliceosome component | Pseudouridylation affects splicing catalysis |
| EFTUD2 | Spliceosome component | Modification impacts spliceosome dynamics |
| DDX23 | Spliceosome component | Pseudouridylation influences RNA helicase activity |
| Cajal body proteins (coilin) | Cajal body structure | Localizes pseudouridylation machinery |
How Is snRNA pseudouridine synthesis Regulated?
snRNA pseudouridylation is regulated by the availability of box H/ACA snoRNPs and pseudouridine synthases, which can be modulated by cellular stress and growth signals. For example, PUS7-mediated pseudouridylation of 7SK snRNA regulates Pol II transcription elongation in response to developmental cues. Additionally, viral infection can alter pseudouridylation patterns to favor viral replication.
snRNA pseudouridine synthesis and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PUS7 | Cancer, transcription regulation | PUS7 knockout cell lines, xenograft models |
| DKC1 | Dyskeratosis congenita | Patient-derived iPSCs, DKC1 mutant mice |
| PUS1 | Mitochondrial myopathy, sideroblastic anemia | PUS1 knockout zebrafish, cell lines |
| KSHV ORF57 | Viral replication | KSHV-infected cells, pseudouridine mapping |
| 7SK snRNA | Transcription elongation | 7SK mutant cells, PUS7 knockdown |
Cancer
Dysregulation of pseudouridine synthases, such as PUS7, has been implicated in cancer progression. PUS7-mediated pseudouridylation of 7SK snRNA regulates transcription elongation, and its loss affects cancer cell proliferation. Targeting snRNA pseudouridylation pathways may offer therapeutic strategies.
Viral infections
Kaposi's sarcoma-associated herpesvirus (KSHV) transcriptome exhibits prevalent pseudouridylation, which is essential for viral replication. This highlights the role of snRNA pseudouridine synthesis in viral pathogenesis and potential antiviral targets.
Developmental disorders
Mutations in DKC1, a box H/ACA snoRNP component, cause dyskeratosis congenita, a disorder linked to defective pseudouridylation and telomere maintenance. This underscores the importance of snRNA pseudouridylation in human development.
From snRNA pseudouridine synthesis-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PUS7 knockout affect snRNA pseudouridylation? | PUS7 knockout cell line (CRISPR-Cas9) |
| What is the role of a specific pseudouridylation site in splicing? | Point mutation of target uridine in snRNA |
| How does pseudouridylation affect snRNP assembly? | Knock-in of tagged snRNP proteins |
| Can overexpression of PUS1 rescue pseudouridylation defects? | Overexpression of PUS1 in mutant cells |
| What are the transcriptome-wide targets of PUS7? | PUS7 knockout followed by Ψ-seq |
| Does DKC1 mutation alter Cajal body dynamics? | DKC1 mutant cells with coilin imaging |
How to Study the snRNA pseudouridine synthesis Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ψ-seq | Pseudouridine sites at base resolution | Transcriptome-wide mapping |
| CRISPR knockout | Gene function loss | PUS7 knockout in cancer cells |
| RNA-seq | Gene expression changes | Splicing analysis after knockout |
| Splicing reporter assay | Splicing efficiency | Impact of pseudouridylation on splicing |
| Immunofluorescence | Cajal body localization | Coilin imaging in mutant cells |
| Mass spectrometry | Pseudouridine quantification | Absolute quantification in snRNA |
| RIP-seq | RNA-protein interactions | snoRNA-snRNA interactions |
Base-resolution pseudouridine sequencing
Absolute quantitative and base-resolution sequencing methods, such as Ψ-seq, enable comprehensive mapping of pseudouridine across the transcriptome, including snRNAs. These techniques are essential for identifying specific modification sites and quantifying changes.
CRISPR-Cas9 knockout screens
Knockout of pseudouridine synthases (e.g., PUS7) followed by RNA-seq and splicing assays can reveal the functional consequences of loss of snRNA pseudouridylation. This approach identifies target genes and pathways affected.
Splicing assays
In vitro and in vivo splicing assays using reporter constructs can measure the impact of pseudouridylation on spliceosome activity. These assays help link modification status to splicing efficiency.
Imaging of Cajal bodies
Fluorescence microscopy of Cajal body markers (e.g., coilin) can assess the localization of pseudouridylation machinery and its dynamics under different conditions.
How CRISPR Can Be Used to Study GO:0031120 snRNA pseudouridine synthesis
Knockout
CRISPR-Cas9 knockout of pseudouridine synthases (e.g., PUS7, PUS1) or box H/ACA snoRNP components (e.g., DKC1) allows researchers to study the loss of snRNA pseudouridylation and its effects on splicing and gene expression.
Point Mutation
Introducing point mutations at specific uridine residues in snRNAs using CRISPR base editing can determine the functional importance of individual pseudouridylation sites.
Knock-in
Knock-in of tagged pseudouridine synthases or snoRNP proteins enables affinity purification and localization studies to dissect the machinery of snRNA pseudouridylation.
Overexpression
Overexpression of wild-type or mutant pseudouridine synthases can rescue or exacerbate phenotypes, helping to establish causality and mechanism.
How EDITGENE Supports snRNA pseudouridine synthesis Research
Researchers studying snRNA pseudouridine synthesis-related genes often need to determine whether a candidate gene is causally involved in the modification process or its downstream effects. EDITGENE provides comprehensive CRISPR services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for snRNA pseudouridine synthesis research.
Frequently Asked Questions About snRNA pseudouridine synthesis
What is snRNA pseudouridine synthesis?
It is the conversion of uridine to pseudouridine in small nuclear RNAs, catalyzed by pseudouridine synthases.
What genes are involved in snRNA pseudouridine synthesis?
Key genes include PUS1, PUS7, DKC1, NHP2, NOP10, and GAR1.
Where does snRNA pseudouridylation occur?
It predominantly occurs in Cajal bodies within the nucleus.
Why is pseudouridylation of snRNA important?
It enhances snRNA stability and spliceosome function, affecting pre-mRNA splicing.
How is snRNA pseudouridylation guided?
Box H/ACA snoRNPs base-pair with target snRNAs to guide modification.
What diseases are linked to defective snRNA pseudouridylation?
Dyskeratosis congenita, cancer, and viral infections.
How can I study snRNA pseudouridine synthesis?
Use Ψ-seq for mapping, CRISPR knockout for functional studies, and splicing assays.
What is the role of PUS7 in snRNA pseudouridylation?
PUS7 modifies 7SK snRNA and regulates Pol II transcription elongation.
Can CRISPR be used to study snRNA pseudouridylation?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are available.
What methods map pseudouridine at base resolution?
Ψ-seq and absolute quantitative sequencing enable transcriptome-wide mapping.
Conclusion
snRNA pseudouridine synthesis (GO:0031120) is a fundamental RNA modification process that impacts spliceosome function, gene expression, and human disease. Understanding its mechanism and regulation offers insights into RNA biology and potential therapeutic targets. EDITGENE provides advanced CRISPR tools to accelerate research in this field.
References
- 1. Hamma T et al.. 2006. Pseudouridine synthases.. Chem Biol 13(11):1125-35 PMID: 17113994
- 3. De Zoysa MD et al.. 2017. Posttranscriptional RNA Pseudouridylation.. Enzymes 41:151-167 PMID: 28601221
- 4. Chen JL et al.. 2024. Pseudouridylation-mediated gene expression modulation.. Biochem J 481(1):1-16 PMID: 38174858
- 5. Xu H et al.. 2024. Absolute quantitative and base-resolution sequencing reveals comprehensive landscape of pseudouridine across the human transcriptome.. Nat Methods 21(11):2024-2033 PMID: 39349603
- 6. Zhao Y et al.. 2025. Pseudouridylation of 7SK by PUS7 regulates Pol II transcription elongation.. Nat Commun 16(1):9595 PMID: 41168165
- 7. Mottram TJ et al.. 2025. Pseudouridine prevalence in Kaposi's sarcoma-associated herpesvirus transcriptome reveals an essential mechanism for viral replication.. Proc Natl Acad Sci U S A 122(38):e2508523122 PMID: 40961145
- 8. Meier UT. 2017. RNA modification in Cajal bodies.. RNA Biol 14(6):693-700 PMID: 27775477
