GO:0008278 cohesin complex: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0008278 (cohesin complex) is a ring-shaped protein complex required for sister chromatid cohesion in eukaryotes.
• The complex is built from SMC heterodimers (SMC1A/SMC1B and SMC3) linked by a kleisin subunit (RAD21, REC8, or RAD21L) and a STAG protein (STAG1, STAG2, or STAG3).
• Cohesin also extrudes DNA loops, a function independent of its canonical cohesion role.
• Mutations in cohesin genes cause cohesinopathies such as Cornelia de Lange syndrome and are frequent in myeloid malignancies including AML.
• Meiotic cohesin variants (REC8, RAD21L, STAG3) are essential for chromosome segregation and recombination.
• CRISPR-based knockout, point mutation, knock-in, and overexpression models are key tools for dissecting cohesin function and disease mechanisms.
Description
The cohesin complex (GO:0008278) is a multi-subunit protein machine that holds sister chromatids together from S phase until anaphase, ensuring faithful chromosome segregation. It is also a major architectural factor that organizes the genome by extruding DNA loops. Because of these dual roles, cohesin is central to gene regulation, DNA repair, and development. Dysregulation of cohesin subunits is linked to human disease, including cancer and developmental disorders. Researchers study cohesin to understand chromosome biology, transcriptional control, and to identify therapeutic targets.
cohesin complex At A Glance
| GO ID | GO:0008278 |
|---|---|
| GO term | cohesin complex |
| Ontology | cellular_component |
| Synonym | 14S cohesin; 9S cohesin; cohesin core heterodimer; nuclear cohesin complex; Smc1-Smc3 complex; SMC complex; SMC/kleisin ring complex |
| Major function | Sister chromatid cohesion and DNA loop extrusion |
| Subunits | SMC1A/SMC1B, SMC3, RAD21/REC8/RAD21L, STAG1/STAG2/STAG3 |
| Associated processes | Chromosome segregation, DNA repair, gene regulation |
| Disease links | Cornelia de Lange syndrome, acute myeloid leukemia, other cancers |
What Is GO:0008278?
GO:0008278 describes a protein complex required for sister chromatid cohesion in eukaryotes. It forms a molecular ring composed of structural maintenance of chromosomes (SMC) proteins and kleisin proteins. In vertebrates, the core is an SMC1 (SMC1A or SMC1B) and SMC3 heterodimer whose hinge domains interact, with a kleisin (RAD21, REC8, or RAD21L) linking the SMC heads, plus one STAG protein (STAG1, STAG2, or STAG3).
Why Is cohesin complex Important in Cell Biology?
Cohesin is essential for genome stability and gene regulation, and its dysfunction leads to developmental disorders and cancer. Understanding its assembly, regulation, and diverse roles provides insight into basic chromosome biology and offers targets for therapeutic intervention.
• Ensures accurate sister chromatid segregation during mitosis and meiosis.
• Mediates DNA loop extrusion to shape 3D genome architecture.
• Facilitates DNA double-strand break repair by holding sister chromatids.
• Regulates gene expression by organizing enhancer-promoter contacts.
• Mutations cause Cornelia de Lange syndrome and related cohesinopathies.
• Recurrently mutated in acute myeloid leukemia and other cancers.
• Meiotic cohesin variants are required for gametogenesis.
• Provides targets for cancer therapy, e.g., via synthetic lethality.
• Serves as a model for studying SMC complex mechanics.
• Enables CRISPR screens to identify cohesin vulnerabilities.
Structure and Composition of cohesin complex
SMC heterodimer formation
In simple terms: Two long proteins, SMC1 and SMC3, pair up to form the core of the ring.
SMC1A (or SMC1B in meiosis) and SMC3 form a heterodimer through their hinge domains, creating a V-shaped structure that is the backbone of the cohesin ring.
Kleisin linkage
In simple terms: A smaller protein called kleisin connects the two SMC heads to close the ring.
The kleisin subunit (RAD21 in mitosis, REC8 or RAD21L in meiosis) binds to the ATPase heads of SMC1 and SMC3, forming a tripartite ring that topologically entraps DNA.
STAG subunit association
In simple terms: A HEAT-repeat protein called STAG binds to kleisin and helps regulate the complex.
One STAG protein (STAG1, STAG2, or STAG3) associates with the kleisin subunit, contributing to cohesin's stability and its interactions with regulatory factors.
Accessory factors and dynamic assembly
In simple terms: Other proteins like NIPBL and PDS5 help load and regulate cohesin on DNA.
Loading of cohesin onto chromatin requires NIPBL and MAU2, while PDS5, WAPL, and sororin modulate its dynamic binding and release.
Key Genes Involved in GO:0008278 cohesin complex
The following genes encode core cohesin subunits and key regulators, representing major research targets.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SMC1A | Core SMC subunit | Mutations in Cornelia de Lange syndrome; loop extrusion studies |
| SMC1B | Meiosis-specific SMC subunit | Meiotic cohesion and recombination |
| SMC3 | Core SMC subunit | Cohesinopathy and cancer mutations |
| RAD21 | Mitotic kleisin | Essential for cohesion; mutated in cancer |
| REC8 | Meiotic kleisin | Required for meiosis; knockout causes infertility |
| RAD21L | Meiotic kleisin | Meiotic-specific cohesion |
| STAG1 | HEAT-repeat subunit | Cohesin stability; synthetic lethality with STAG2 loss |
| STAG2 | HEAT-repeat subunit | Frequently mutated in AML and other cancers |
| STAG3 | Meiotic STAG subunit | Meiotic cohesion; mutations cause premature ovarian failure |
| NIPBL | Cohesin loader | Mutated in Cornelia de Lange syndrome |
| MAU2 | Cohesin loader | Required for cohesin loading |
| WAPL | Cohesin release factor | Regulates cohesin turnover |
| PDS5A | Cohesin-associated factor | Modulates cohesion and loop extrusion |
| PDS5B | Cohesin-associated factor | Modulates cohesion and loop extrusion |
| ESCO1 | Acetyltransferase | Acetylates SMC3 to establish cohesion |
| ESCO2 | Acetyltransferase | Mutated in Roberts syndrome |
| CDCA5 | Sororin | Stabilizes cohesin on chromatin |
How Is cohesin complex Regulated?
Cohesin function is regulated by post-translational modifications and accessory proteins. Acetylation of SMC3 by ESCO1/2 stabilizes cohesin on chromatin, while WAPL promotes its release. Phosphorylation of cohesin subunits by Polo-like kinase and Aurora B regulates its dynamics during mitosis. In meiosis, cohesin is regulated by meiosis-specific factors and phosphorylation to ensure stepwise loss.
cohesin complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NIPBL | Cornelia de Lange syndrome | Knockout or point mutation in cell lines; patient iPSCs |
| STAG2 | AML and solid tumors | Knockout in hematopoietic cells; xenograft models |
| SMC1A | Cornelia de Lange syndrome; cancer | Knock-in of patient mutations; overexpression |
| REC8 | Meiotic failure; infertility | Knockout in mouse models; meiosis-competent cell lines |
| ESCO2 | Roberts syndrome | Knockout or point mutation in fibroblasts |
Cohesinopathies: Cornelia de Lange syndrome and Roberts syndrome
Mutations in NIPBL, SMC1A, SMC3, RAD21, and ESCO2 cause developmental disorders characterized by growth retardation, limb defects, and intellectual disability. These cohesinopathies highlight the importance of cohesin in gene regulation and development.
Cohesin mutations in acute myeloid leukemia
Recurrent mutations in cohesin genes (STAG2, RAD21, SMC1A, SMC3) are found in myeloid malignancies, including AML, and are associated with altered chromatin architecture and gene expression. Targeting cohesin-deficient cells is a therapeutic strategy.
Cohesin in other cancers
STAG2 mutations occur in bladder cancer, glioblastoma, and Ewing sarcoma, among others. Cohesin dysfunction contributes to aneuploidy and tumor heterogeneity.
Meiotic cohesin defects and infertility
Mutations in REC8, RAD21L, and STAG3 cause meiotic arrest and premature ovarian failure, underscoring the role of meiotic cohesin in fertility.
From cohesin complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of STAG2 affect proliferation? | STAG2 knockout cell lines |
| How do point mutations in SMC1A affect cohesin function? | SMC1A point-mutation knock-in |
| What is the effect of cohesin overexpression? | Cohesin subunit overexpression |
| Where does cohesin bind in the genome? | Tagged knock-in (e.g., HiBiT, GFP) for ChIP-seq |
| What is the role of REC8 in meiosis? | REC8 knockout in meiosis-competent cells |
| Can cohesin mutations be targeted therapeutically? | CRISPR library screening in cohesin-mutant cells |
How to Study the cohesin complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Hi-C | 3D genome organization | Assessing loop extrusion and TADs |
| ChIP-seq | Genome-wide binding sites | Mapping cohesin occupancy |
| Live-cell imaging | Protein dynamics | Visualizing cohesin loading and turnover |
| CRISPR knockout screens | Gene essentiality and synthetic lethality | Identifying therapeutic targets |
| Proteomics | Protein interactions | Identifying cohesin-associated factors |
| RNA-seq | Transcriptional changes | Evaluating gene expression upon cohesin loss |
| Single-molecule imaging | DNA loop extrusion | Mechanistic studies of cohesin |
| Flow cytometry | Cell cycle and aneuploidy | Assessing chromosome segregation defects |
Chromosome conformation capture (Hi-C)
Hi-C measures 3D genome organization and can reveal changes in loop extrusion upon cohesin perturbation.
Chromatin immunoprecipitation sequencing (ChIP-seq)
ChIP-seq for cohesin subunits or tagged proteins maps binding sites genome-wide, providing insights into its role in gene regulation.
Live-cell imaging
Fluorescently tagged cohesin allows real-time visualization of its dynamics during the cell cycle.
CRISPR screens
Genome-wide CRISPR knockout screens identify synthetic lethal interactions and vulnerabilities in cohesin-mutant cells.
How CRISPR Can Be Used to Study GO:0008278 cohesin complex
Knockout
CRISPR knockout of cohesin genes (e.g., STAG2, RAD21) in cell lines models loss-of-function and reveals effects on proliferation, genome stability, and gene expression.
Point Mutation
Introducing patient-specific point mutations (e.g., in SMC1A or SMC3) via CRISPR knock-in allows study of subtle structural and functional defects.
Knock-in
Tagging endogenous cohesin subunits with fluorescent or epitope tags enables live-cell imaging and ChIP-seq without overexpression artifacts.
Overexpression
Overexpressing cohesin subunits or mutants can test dominant-negative effects and gain-of-function phenotypes in cancer models.
How EDITGENE Supports cohesin complex Research
Researchers studying cohesin complex-related genes often need to determine whether a candidate gene is causally involved in cohesion, gene regulation, or disease. EDITGENE provides tailored CRISPR services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for cohesin complex research.
Frequently Asked Questions About cohesin complex
What is the cohesin complex?
The cohesin complex is a ring-shaped protein complex that holds sister chromatids together and organizes DNA loops.
What genes are involved in the cohesin complex?
Core genes include SMC1A, SMC1B, SMC3, RAD21, REC8, RAD21L, STAG1, STAG2, and STAG3.
What is the function of GO:0008278?
GO:0008278 describes the cohesin complex, which is required for sister chromatid cohesion and DNA loop extrusion.
How is cohesin loaded onto DNA?
Loading requires the NIPBL-MAU2 complex, which opens the cohesin ring and entraps DNA.
What diseases are associated with cohesin mutations?
Mutations cause Cornelia de Lange syndrome, Roberts syndrome, and are frequent in acute myeloid leukemia and other cancers.
What is the role of cohesin in meiosis?
Meiotic cohesin variants (REC8, RAD21L, STAG3) are essential for chromosome segregation and recombination.
How can I study cohesin complex function?
Use CRISPR knockout, knock-in, ChIP-seq, Hi-C, and live-cell imaging.
What are cohesinopathies?
Developmental disorders caused by mutations in cohesin genes, such as Cornelia de Lange syndrome.
Is cohesin involved in cancer?
Yes, cohesin genes are recurrently mutated in AML and solid tumors, and cohesin dysfunction promotes aneuploidy.
What CRISPR models are available for cohesin research?
EDITGENE offers knockout, point mutation, knock-in, overexpression, and library screening services for cohesin genes.
Conclusion
The cohesin complex (GO:0008278) is a fundamental regulator of chromosome structure and gene expression, with critical roles in development and disease. Continued research using advanced CRISPR models will unravel its mechanisms and therapeutic potential.
References
- 1. Ishiguro KI. 2019. The cohesin complex in mammalian meiosis.. Genes Cells 24(1):6-30 PMID: 30479058
- 2. Golov AK et al.. 2024. Cohesin Complex: Structure and Principles of Interaction with DNA.. Biochemistry (Mosc) 89(4):585-600 PMID: 38831498
- 3. Davidson IF et al.. 2019. DNA loop extrusion by human cohesin.. Science 366(6471):1338-1345 PMID: 31753851
- 4. Mintzas K et al.. 2019. Emerging strategies to target the dysfunctional cohesin complex in cancer.. Expert Opin Ther Targets 23(6):525-537 PMID: 31020869
- 5. Rankin S. 2015. Complex elaboration: making sense of meiotic cohesin dynamics.. FEBS J 282(13):2426-43 PMID: 25895170
- 6. Peters JM et al.. 2008. The cohesin complex and its roles in chromosome biology.. Genes Dev 22(22):3089-114 PMID: 19056890
- 7. Pezic D et al.. 2017. More to cohesin than meets the eye: complex diversity for fine-tuning of function.. Curr Opin Genet Dev 43:93-100 PMID: 28189962
- 8. Heimbruch KE et al.. 2021. A cohesive look at leukemogenesis: The cohesin complex and other driving mutations in AML.. Neoplasia 23(3):337-347 PMID: 33621854
