GO:0071020 post-spliceosomal complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0071020 (post-spliceosomal complex) is a cellular component defined as a spliceosomal complex formed after the second splicing event, containing the spliced product, the excised intron, and three snRNPs including U5.
• The complex is also known as mammalian spliceosomal complex C2 or yeast spliceosomal complex A2-3.
• It represents a late stage in pre-mRNA splicing, after exon ligation and before complex disassembly and snRNP recycling.
• The U6 snRNA within the complex undergoes 3'-cyclic phosphorylation, which recruits the recycling factor p110 via LSm proteins.
• Studying this complex helps understand splicing fidelity, intron turnover, and snRNP recycling, with implications for diseases linked to splicing defects.
• Research methods include affinity purification, RNA-seq, proteomics, and CRISPR-based perturbation of splicing factors.
Description
The post-spliceosomal complex (GO:0071020) is a cellular component that forms after the second catalytic step of pre-mRNA splicing. It contains the ligated exon product, the excised intron lariat, and three small nuclear ribonucleoproteins (snRNPs), including U5. This complex is a key intermediate in the splicing cycle, marking the transition from catalysis to disassembly and recycling of splicing machinery. Understanding its composition and dynamics is essential for researchers studying RNA processing, gene expression regulation, and splicing-related diseases. The complex has been characterized in both mammalian and yeast systems, where it is known as complex C2 or A2-3, respectively. Its study provides insights into how cells maintain splicing efficiency and fidelity, and how defects in these processes can lead to disease.
post-spliceosomal complex At A Glance
| GO ID | GO:0071020 |
|---|---|
| GO term | post-spliceosomal complex |
| Ontology | cellular_component |
| Synonym | mammalian spliceosomal complex C2, yeast spliceosomal complex A2-3 |
| Major function | Contains the spliced product, excised intron, and three snRNPs including U5 after the second splicing event |
| Related process | Pre-mRNA splicing, spliceosome disassembly, snRNP recycling |
| Key modification | 3'-cyclic phosphorylation of U6 snRNA recruits p110 via LSm proteins |
| Cellular location | Nucleus |
What Is GO:0071020?
According to the Gene Ontology, GO:0071020 (post-spliceosomal complex) is a spliceosomal complex that is formed following the second splicing event and contains the spliced product, the excised intron, and three snRNPs, including U5. This definition captures a late-stage assembly that exists after exon ligation but before the complex is disassembled and its components recycled.
Why Is post-spliceosomal complex Important in Cell Biology?
The post-spliceosomal complex is important because it represents a critical checkpoint in the splicing cycle where the products of splicing are released and the splicing machinery is prepared for recycling. Defects in this stage can lead to accumulation of unspliced or mis-spliced transcripts, which are associated with various diseases including cancer and neurodegeneration. Studying this complex helps elucidate mechanisms of splicing fidelity and provides potential targets for therapeutic intervention.
• Marks the completion of the second splicing event and ensures proper exon ligation.
• Facilitates the release of spliced mRNA for export and translation.
• Enables recycling of snRNPs and splicing factors for subsequent rounds of splicing.
• Its U6 snRNA modification (3'-cyclic phosphorylation) is crucial for recruiting recycling factor p110.
• Dysregulation of splicing is linked to cancer, neurodegenerative diseases, and genetic disorders.
• Provides a target for understanding splicing-related drug mechanisms.
• Helps in studying intron turnover and RNA quality control.
• Offers insights into evolutionary conservation of splicing machinery.
What Happens During post-spliceosomal complex?
Formation after second splicing event
In simple terms: After the intron is cut out and exons are joined, the splicing machinery rearranges into a new complex.
The post-spliceosomal complex forms immediately after the second catalytic step of splicing, which involves exon ligation and release of the intron lariat. At this stage, the complex contains the spliced product, the excised intron, and three snRNPs including U5.
U6 snRNA modification and p110 recruitment
In simple terms: A chemical tag is added to U6 snRNA, which acts like a signal to bring in a recycling factor.
The U6 snRNA within the post-spliceosomal complex undergoes 3'-cyclic phosphorylation, which is recognized by LSm proteins that recruit the recycling factor p110. This modification is essential for the disassembly of the complex and recycling of splicing components.
Disassembly and recycling
In simple terms: The complex falls apart, and its parts are reused for new rounds of splicing.
Following p110 recruitment, the post-spliceosomal complex is disassembled, releasing the spliced mRNA, intron lariat, and snRNPs for reuse. This step is critical for maintaining splicing efficiency and cellular homeostasis.
Key Genes Involved in GO:0071020 post-spliceosomal complex
The following genes and proteins are key components or regulators of the post-spliceosomal complex, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| U5 snRNP | snRNP component of the complex | Essential for splicing catalysis and complex stability |
| U6 snRNA | Catalytic RNA that undergoes 3'-cyclic phosphorylation | Modification recruits p110 for recycling |
| LSm proteins | Bind U6 snRNA and recruit p110 | Mediate recycling factor recruitment |
| p110 | Recycling factor | Facilitates complex disassembly |
| Prp8 | U5 snRNP protein | Core component of spliceosome |
| Prp19 | Component of NTC complex | Involved in spliceosome activation |
| Snu114 | U5 snRNP GTPase | Regulates splicing dynamics |
| Brr2 | RNA helicase | Unwinds RNA during splicing |
| Prp43 | RNA helicase | Disassembles spliceosome |
| Npl3 | SR-like protein | Couples splicing to export |
| Sub2 | RNA helicase | Involved in spliceosome disassembly |
| Prp22 | RNA helicase | Releases mRNA after splicing |
| Cwc22 | Splicing factor | Required for exon junction complex deposition |
| Prp16 | RNA helicase | Proofreads splicing |
| Slx5 | E3 ligase | Regulates splicing factors |
| Prp45 | Splicing factor | Involved in complex stability |
| U2 snRNP | snRNP component | Present in earlier complexes but may influence post-spliceosomal stage |
How Is post-spliceosomal complex Regulated?
The post-spliceosomal complex is regulated by post-translational modifications and RNA modifications. Specifically, 3'-cyclic phosphorylation of U6 snRNA is a key regulatory event that recruits p110 through LSm proteins, controlling the timing of complex disassembly. This modification ensures proper recycling of splicing components and maintains splicing efficiency.
post-spliceosomal complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| U6 snRNA | Cancer, splicing dysregulation | Knockout of U6 modification enzymes in cell lines |
| p110 | Splicing-related disorders | Overexpression or knockout of p110 in mammalian cells |
| LSm proteins | Neurodegeneration | Point mutations in LSm genes in yeast or human cells |
| Prp8 | Retinitis pigmentosa | Knock-in of patient mutations in cell models |
| Prp43 | Cancer | Knockout or knockdown in cancer cell lines |
Splicing defects in cancer
Mutations in splicing factors that affect the post-spliceosomal complex can lead to aberrant splicing patterns, contributing to cancer development. For example, dysregulation of U6 snRNA modification or p110 recruitment may promote oncogenic splicing variants.
Neurodegenerative disorders
Defects in spliceosome disassembly and recycling have been linked to neurodegeneration, as impaired splicing leads to accumulation of toxic RNA species. The post-spliceosomal complex is a potential target for understanding these pathologies.
From post-spliceosomal complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of U6 3'-cyclic phosphorylation in complex disassembly? | Point mutation of U6 snRNA in cell lines |
| How does p110 recruitment affect splicing efficiency? | Knockout of p110 in mammalian cells |
| What are the protein interactions in the post-spliceosomal complex? | Tagged knock-in of LSm proteins for affinity purification |
| Does overexpression of p110 rescue splicing defects? | Overexpression of p110 in mutant cells |
| What is the effect of LSm mutations on complex stability? | Knock-in of patient-derived LSm mutations |
| Can CRISPR screening identify novel regulators of complex disassembly? | CRISPR library screening in splicing reporter cells |
How to Study the post-spliceosomal complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Affinity purification | Protein interactions | Identifying complex components |
| Mass spectrometry | Protein composition and modifications | Detecting post-translational changes |
| RNA-seq | Splicing efficiency and products | Quantifying spliced mRNA and intron lariats |
| In vitro splicing assay | Catalytic activity | Studying mutant effects |
| CRISPR knockout | Gene function | Loss-of-function studies |
| CRISPR knock-in | Mutant protein behavior | Modeling patient mutations |
| Cryo-EM | 3D structure | Visualizing complex architecture |
Affinity purification and mass spectrometry
Affinity purification of tagged snRNP components followed by mass spectrometry can identify proteins associated with the post-spliceosomal complex. This method reveals dynamic interactions and post-translational modifications.
RNA sequencing and splicing assays
RNA-seq and in vitro splicing assays can measure the efficiency of complex formation and disassembly by detecting spliced products and intron lariats. These methods are used to study the impact of mutations in complex components.
CRISPR-based perturbation
CRISPR knockout or knock-in of genes encoding complex components allows functional studies of the post-spliceosomal complex in cells. This approach can reveal roles in splicing fidelity and disease.
Structural biology
Cryo-EM and X-ray crystallography can provide structural insights into the post-spliceosomal complex, revealing how snRNPs and splicing factors are arranged. These studies help understand the mechanism of disassembly.
How CRISPR Can Be Used to Study GO:0071020 post-spliceosomal complex
Knockout
CRISPR knockout of genes encoding post-spliceosomal complex components, such as LSm proteins or p110, can reveal their essential roles in splicing and cell viability. These models help determine which factors are required for complex disassembly.
Point Mutation
Introducing point mutations in U6 snRNA or protein factors via CRISPR can mimic disease-associated variants and test their effects on complex stability and recycling. This approach is useful for studying the 3'-cyclic phosphorylation site.
Knock-in
Knock-in of tagged versions of complex components, such as GFP-tagged LSm proteins, allows live-cell imaging and affinity purification to track complex dynamics. This helps in understanding the spatiotemporal regulation of the post-spliceosomal complex.
Overexpression
Overexpression of p110 or other recycling factors using CRISPR activation or cDNA delivery can test whether increased levels enhance splicing efficiency or rescue defects. This is valuable for therapeutic target validation.
How EDITGENE Supports post-spliceosomal complex Research
Researchers studying post-spliceosomal complex-related genes often need to determine whether a candidate gene is causally involved in splicing regulation, complex stability, or disease. EDITGENE provides comprehensive CRISPR services to enable such investigations with high precision and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for post-spliceosomal complex research.
Frequently Asked Questions About post-spliceosomal complex
What is the post-spliceosomal complex?
The post-spliceosomal complex (GO:0071020) is a spliceosomal complex formed after the second splicing event, containing the spliced product, excised intron, and three snRNPs including U5.
What genes are involved in the post-spliceosomal complex?
Key genes include U6 snRNA, LSm proteins, p110, and various snRNP components like U5.
What is the function of GO:0071020?
It functions in the late stage of pre-mRNA splicing, facilitating the release of spliced mRNA and recycling of splicing factors.
How is the post-spliceosomal complex regulated?
It is regulated by 3'-cyclic phosphorylation of U6 snRNA, which recruits p110 via LSm proteins.
What diseases are associated with post-spliceosomal complex defects?
Defects are linked to cancer and neurodegenerative disorders due to aberrant splicing.
What methods are used to study the post-spliceosomal complex?
Methods include affinity purification, mass spectrometry, RNA-seq, and CRISPR-based perturbation.
What is the synonym for post-spliceosomal complex?
It is also known as mammalian spliceosomal complex C2 or yeast spliceosomal complex A2-3.
Why is U6 snRNA modification important?
3'-cyclic phosphorylation of U6 snRNA is crucial for recruiting p110 and disassembling the complex.
Can CRISPR be used to study the post-spliceosomal complex?
Yes, CRISPR knockout, knock-in, and point mutations can model complex component functions.
What is the role of p110 in splicing?
p110 is a recycling factor recruited to the post-spliceosomal complex to facilitate disassembly.
Conclusion
The post-spliceosomal complex (GO:0071020) is a critical intermediate in the splicing cycle, ensuring proper mRNA maturation and snRNP recycling. Its study offers insights into splicing regulation and disease mechanisms, and CRISPR-based models are powerful tools for dissecting its components. EDITGENE provides comprehensive services to support such research, from knockout to overexpression and screening.
References
- 1. Licht K et al.. 2008. 3'-cyclic phosphorylation of U6 snRNA leads to recruitment of recycling factor p110 through LSm proteins.. RNA 14(8):1532-8 PMID: 18567812
