GO:1990477 MTREC complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1990477 defines the MTREC complex, a nuclear RNA surveillance machine conserved from fission yeast to humans.
• MTREC is composed of Red1, Mtl1, Red5, Rmn1, Iss10/Pir1, and Ars2/Pir2, and recruits the nuclear exosome to Mmi1-bound RNAs.
• It targets cryptic unstable transcripts (CUTs) and unspliced pre-mRNAs for degradation, safeguarding the transcriptome.
• MTREC is essential for meiotic gene silencing and for preventing aberrant expression of meiosis-specific genes during vegetative growth.
• The human ortholog, CBCN/PAXT, shares structural and functional features with MTREC, linking it to RNA quality control in higher eukaryotes.
• CRISPR-based knockout, point mutation, knock-in, and overexpression models enable precise dissection of MTREC subunit functions.
Description
The MTREC complex (GO:1990477) is a nuclear RNA surveillance assembly that targets unstable transcripts for degradation by the exosome. First characterized in Schizosaccharomyces pombe, it is required for the recruitment of the nuclear exosome to Mmi1 nuclear foci, where it silences meiotic genes during vegetative growth. The complex is also known as the NURS complex and is related to the human CBCN/PAXT complex, highlighting its evolutionary conservation. Understanding MTREC provides fundamental insights into RNA quality control, heterochromatin formation, and gene regulation. Researchers study MTREC to uncover how cells distinguish aberrant from functional RNAs and to model human diseases linked to RNA processing defects.
MTREC complex At A Glance
| GO ID | GO:1990477 |
|---|---|
| GO term | MTREC complex |
| Ontology | cellular_component |
| Synonym | Mtl1-Red1 core complex, NURS complex, PAXT complex |
| Major function | Recruits nuclear exosome to Mmi1-bound RNAs for degradation; targets CUTs and unspliced pre-mRNAs |
| Subunits | Red1, Mtl1, Red5, Rmn1, Iss10/Pir1, Ars2/Pir2 |
| Conservation | Related to human CBCN/PAXT complex |
| Associated process | Meiotic gene silencing, RNA quality control, heterochromatin assembly |
What Is GO:1990477?
The MTREC complex is a protein complex formed by the RNA-binding protein Red1, the RNA helicase Mtl1, Red5, Rmn1, Iss10/Pir1, and Ars2/Pir2. It is required for the recruitment of the nuclear exosome to Mmi1 nuclear foci and is likely related to the human CBCN complex. This complex is also known as the RNA silencing (NURS) complex.
Why Is MTREC complex Important in Cell Biology?
The MTREC complex is a central node in nuclear RNA surveillance, ensuring that cryptic and aberrant transcripts are eliminated before they can be translated. Its role in recruiting the exosome to Mmi1 targets is critical for meiotic gene silencing and for preventing inappropriate heterochromatin formation. Dysregulation of MTREC or its human counterpart has been linked to defects in RNA processing and genome stability, making it a model for studying RNA quality control in health and disease.
• Maintains transcriptome integrity by degrading CUTs and unspliced pre-mRNAs.
• Silences meiotic genes during vegetative growth to prevent inappropriate meiosis.
• Recruits the nuclear exosome to Mmi1-bound RNAs via a conserved mechanism.
• Contributes to heterochromatin assembly at repetitive DNA elements.
• Serves as a model for human RNA quality control (CBCN/PAXT).
• Involved in the regulation of poly(A) polymerase Pla1 activity.
• Required for proper meiotic transcript maturation in fission yeast.
• Provides a paradigm for studying RNA-protein complex assembly and function.
• Potential target for antifungal or anticancer strategies targeting RNA surveillance.
• Enables CRISPR-based functional genomics of RNA processing pathways.
Structure and Composition of MTREC complex
Red1: The Scaffold Subunit
In simple terms: Red1 acts like a molecular hub that holds the other parts of the MTREC complex together.
Red1 is an RNA-binding protein that serves as a conserved scaffold for the MTREC/PAXT complex. It orchestrates the assembly of MTREC submodules and directly binds the Mtl1 helicase arch domain. Structural analysis of Red1 revealed a conserved architecture that mediates interactions with other subunits and RNA targets.
Mtl1: The RNA Helicase
In simple terms: Mtl1 is a motor that helps unwind RNA structures so other factors can access the transcript.
Mtl1 is an RNA helicase that interacts with Red1 through its arch domain. It is part of the Mtl1-Red1 core complex, which is essential for MTREC function. The helicase activity of Mtl1 is thought to facilitate the remodeling of RNA-protein complexes during surveillance.
Red5, Rmn1, Iss10/Pir1, and Ars2/Pir2
In simple terms: These additional subunits help MTREC recognize its targets and recruit the exosome.
Red5, Rmn1, Iss10/Pir1, and Ars2/Pir2 are integral components of the MTREC complex. They are required for the recruitment of the nuclear exosome to Mmi1 nuclear foci. Iss10/Pir1 and Ars2/Pir2 are also known as Pir1 and Pir2, respectively, and contribute to the RNA silencing function of the complex.
Assembly and Conservation
In simple terms: The MTREC complex is built in a stepwise manner and is similar to a human complex called CBCN/PAXT.
The assembly of MTREC involves the formation of a core subcomplex containing Red1 and Mtl1, followed by the addition of other subunits. This architecture is conserved in the human CBCN/PAXT complex, which shares structural and functional similarities. The conservation underscores the importance of MTREC as a model for understanding RNA surveillance in higher eukaryotes.
Key Genes Involved in GO:1990477 MTREC complex
The following genes and proteins are the core components and regulators of the MTREC complex, as identified in fission yeast and related organisms.
| Gene | Major Role | Research Relevance |
|---|---|---|
| red1 | RNA-binding scaffold; orchestrates MTREC assembly | Central to complex integrity; target for structural studies |
| mtl1 | RNA helicase; remodels RNA for degradation | Essential for MTREC function; interacts with Red1 |
| red5 | MTREC subunit; required for exosome recruitment | Links MTREC to RNA degradation |
| rmn1 | MTREC subunit; involved in RNA silencing | Contributes to NURS complex activity |
| iss10 (pir1) | MTREC subunit; part of RNA silencing complex | Modulates MTREC targets |
| ars2 (pir2) | MTREC subunit; part of RNA silencing complex | Modulates MTREC targets |
| mmi1 | YTH-RNA-binding protein; recruits MTREC to target RNAs | Defines MTREC target specificity |
| pla1 | Canonical poly(A) polymerase; interacts with MTREC | Adds poly(A) tails to MTREC targets |
| dis3 | Nuclear exosome catalytic subunit | Degrades MTREC-targeted RNAs |
| rrp6 | Nuclear exosome subunit | Processes MTREC targets |
| clr4 | Histone methyltransferase; heterochromatin assembly | Nucleated by RNA quality control factors |
| swi6 | Heterochromatin protein 1 homolog | Binds H3K9me and maintains silencing |
| rad24 | 14-3-3 protein; regulates MTREC targets | Links signaling to RNA surveillance |
| asp1 | Inositol pyrophosphatase; affects MTREC targets | Synthetic growth defects with rad24Δ |
| mtr4 | RNA helicase; exosome cofactor | Assists in RNA degradation |
| air2 | Zinc-finger protein; TRAMP complex subunit | Polyadenylates MTREC targets |
| cid14 | Poly(A) polymerase; TRAMP subunit | Polyadenylates MTREC targets |
| trf4 | Poly(A) polymerase; TRAMP subunit | Polyadenylates MTREC targets |
How Is MTREC complex Regulated?
MTREC activity is regulated by its interaction with Mmi1, which binds specific RNAs and recruits the complex to nuclear foci. The poly(A) polymerase Pla1 modulates MTREC targets by adding poly(A) tails that influence RNA stability. Additionally, the 14-3-3 protein Rad24 and the inositol pyrophosphatase Asp1 affect MTREC-targeted mRNAs, as rad24Δ asp1-H397A synthetic growth defects are alleviated by a Pla1 active site mutation. These regulatory layers ensure precise control of RNA surveillance.
MTREC complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| red1 | RNA processing defects; cancer | Knockout in S. pombe; human cell lines |
| mtl1 | RNA surveillance defects | Point mutation in helicase domain |
| mmi1 | Meiotic gene silencing defects | Knockout and overexpression |
| clr4 | Heterochromatin assembly; cancer | Knockout in S. pombe |
| pla1 | RNA stability; cancer | Point mutation Y86D |
MTREC and Cancer
The human ortholog of MTREC, CBCN/PAXT, is involved in RNA quality control pathways that are often dysregulated in cancer. Defects in RNA surveillance can lead to the accumulation of aberrant transcripts that promote oncogenesis. Studying MTREC provides a model for understanding how RNA processing errors contribute to cancer.
MTREC and Neurodegeneration
RNA processing defects are a hallmark of neurodegenerative diseases. The conserved function of MTREC in degrading aberrant RNAs suggests that its human counterpart may play a role in neuronal RNA homeostasis. Further research is needed to establish direct links.
MTREC and Heterochromatin-Related Diseases
MTREC contributes to heterochromatin assembly at repetitive elements through the recruitment of Clr4/SUV39H. Dysregulation of heterochromatin is associated with various diseases, including cancer and developmental disorders. This connection highlights the broader impact of MTREC on genome stability.
From MTREC complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of Red1 in MTREC assembly? | Knockout of red1 in S. pombe |
| How does Mtl1 helicase activity affect RNA surveillance? | Point mutation in mtl1 helicase domain |
| What are the targets of MTREC? | Knockout of core subunits followed by RNA-seq |
| How does MTREC recruit the exosome? | Tagged knock-in of exosome subunits |
| Does overexpression of Mmi1 alter MTREC function? | Overexpression of mmi1 |
| How does Pla1 mutation affect MTREC targets? | Point mutation pla1-Y86D |
How to Study the MTREC complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| RNA-seq | Transcript abundance and processing | Identify MTREC targets |
| Co-IP/MS | Protein-protein interactions | Define MTREC subunits |
| Cryo-EM | 3D structure of complexes | Determine MTREC architecture |
| Fluorescence microscopy | Localization of proteins and RNA | Visualize Mmi1 foci |
| CRISPR knockout | Gene function | Study MTREC subunit roles |
| CRISPR point mutation | Specific amino acid function | Analyze helicase activity |
| CRISPR knock-in | Tagged protein expression | Track endogenous proteins |
| Overexpression | Gain-of-function effects | Study Mmi1 dosage |
RNA-seq and Transcriptomics
RNA-seq is used to identify MTREC target RNAs by comparing wild-type and mutant strains. This method reveals the accumulation of CUTs and unspliced pre-mRNAs upon MTREC disruption.
Proteomics and Co-immunoprecipitation
Co-immunoprecipitation coupled with mass spectrometry identifies MTREC subunits and interacting partners. This approach has defined the core components and their stoichiometry.
Structural Biology
X-ray crystallography and cryo-EM have provided structural insights into the Red1 scaffold and its interactions with Mtl1. These studies reveal the molecular architecture of the complex.
Imaging and Live-Cell Microscopy
Fluorescence microscopy visualizes Mmi1 nuclear foci and MTREC recruitment in live cells. This method is used to study the dynamics of RNA surveillance.
How CRISPR Can Be Used to Study GO:1990477 MTREC complex
Knockout
CRISPR knockout of MTREC subunits such as red1, mtl1, or red5 in S. pombe leads to the accumulation of target RNAs and defects in meiotic gene silencing. These models are essential for identifying the full set of MTREC targets and for dissecting subunit-specific functions.
Point Mutation
Point mutations in the helicase domain of Mtl1 or the active site of Pla1 (e.g., Y86D) allow precise interrogation of catalytic activities without disrupting complex assembly. Such models have revealed the role of Pla1 in MTREC-mediated RNA degradation.
Knock-in
Tagged knock-in of MTREC subunits (e.g., GFP or TAP tags) enables endogenous protein localization and interaction studies. These models are used to track MTREC recruitment to Mmi1 foci and to purify the complex for proteomics.
Overexpression
Overexpression of Mmi1 or MTREC subunits can titrate components and reveal dosage-sensitive phenotypes. This approach is useful for studying the regulation of RNA surveillance and for identifying suppressors.
How EDITGENE Supports MTREC complex Research
Researchers studying MTREC complex-related genes often need to determine whether a candidate gene is causally involved in RNA surveillance, meiotic silencing, or heterochromatin assembly. EDITGENE provides comprehensive CRISPR services to generate precisely engineered cell models for such functional studies.
Contact EDITGENE today to design your custom CRISPR model for MTREC complex research.
Frequently Asked Questions About MTREC complex
What is the MTREC complex?
The MTREC complex is a nuclear RNA surveillance machine that recruits the exosome to degrade cryptic and aberrant RNAs.
What genes are involved in the MTREC complex?
Core genes include red1, mtl1, red5, rmn1, iss10/pir1, and ars2/pir2.
What is the function of GO:1990477?
GO:1990477 describes the MTREC complex, which is required for exosome recruitment to Mmi1 foci and RNA silencing.
How does MTREC recruit the exosome?
MTREC interacts with Mmi1-bound RNAs and directly recruits the nuclear exosome for degradation.
What are the targets of MTREC?
MTREC targets cryptic unstable transcripts (CUTs) and unspliced pre-mRNAs.
Is MTREC conserved in humans?
Yes, MTREC is related to the human CBCN/PAXT complex.
What diseases are associated with MTREC?
Dysregulation of RNA surveillance is linked to cancer and neurodegeneration.
How can I study MTREC using CRISPR?
CRISPR knockout, point mutation, knock-in, and overexpression models enable functional dissection of MTREC subunits.
What methods are used to study MTREC?
RNA-seq, co-IP/MS, cryo-EM, and fluorescence microscopy are commonly used.
What is the NURS complex?
NURS is a synonym for the MTREC complex, reflecting its role in RNA silencing.
Conclusion
The MTREC complex (GO:1990477) is a conserved RNA surveillance assembly essential for targeting aberrant transcripts to the nuclear exosome. Its study illuminates fundamental mechanisms of RNA quality control, meiotic silencing, and heterochromatin formation. With CRISPR-based models, researchers can now dissect the precise contributions of each subunit to these processes. EDITGENE provides the tools to accelerate this research and uncover new therapeutic targets.
References
- 1. Soni K et al.. 2023. Mechanistic insights into RNA surveillance by the canonical poly(A) polymerase Pla1 of the MTREC complex.. Nat Commun 14(1):772 PMID: 36774373
- 2. Shichino Y et al.. 2020. Meiotic gene silencing complex MTREC/NURS recruits the nuclear exosome to YTH-RNA-binding protein Mmi1.. PLoS Genet 16(2):e1008598 PMID: 32012158
- 3. Foucher AE et al.. 2022. Structural analysis of Red1 as a conserved scaffold of the RNA-targeting MTREC/PAXT complex.. Nat Commun 13(1):4969 PMID: 36002457
- 4. Zhou Y et al.. 2015. The fission yeast MTREC complex targets CUTs and unspliced pre-mRNAs to the nuclear exosome.. Nat Commun 6:7050 PMID: 25989903
- 5. Khanduja JS et al.. 2024. RNA quality control factors nucleate Clr4/SUV39H and trigger constitutive heterochromatin assembly.. Cell 187(13):3262-3283.e23 PMID: 38815580
- 6. Garg A et al.. 2023. Fission yeast poly(A) polymerase active site mutation Y86D alleviates the rad24Δ asp1-H397A synthetic growth defect and up-regulates mRNAs targeted by MTREC and Mmi1.. RNA 29(11):1738-1753 PMID: 37586723
- 7. Dobrev N et al.. 2021. The zinc-finger protein Red1 orchestrates MTREC submodules and binds the Mtl1 helicase arch domain.. Nat Commun 12(1):3456 PMID: 34103492
- 8. Marayati BF et al.. 2016. The fission yeast MTREC and EJC orthologs ensure the maturation of meiotic transcripts during meiosis.. RNA 22(9):1349-59 PMID: 27365210
