GO:0000070 mitotic sister chromatid segregation: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0000070 mitotic sister chromatid segregation is the cell cycle process in which replicated chromosomes are organized and physically separated into two daughter sets during mitosis.
• Sister chromatid cohesion, established by the cohesin complex and regulated by Wapl, is essential for proper chromosome alignment and segregation.
• Centromere assembly and asymmetric centromere behavior can drive biased sister chromatid segregation in stem cells, linking segregation to cell fate.
• Defects in mitotic sister chromatid segregation can lead to aneuploidy, a hallmark of many cancers and developmental disorders.
• Key genes include cohesins (SMC1A, SMC3, RAD21, STAG1/2), centromere proteins (CENPA, CENPB, CENPC), and mitotic kinases (AURKA, AURKB, PLK1).
• CRISPR-based knockout, point mutation, knock-in, and overexpression models enable causal dissection of segregation genes in human cells.
Description
Mitotic sister chromatid segregation (GO:0000070) is a fundamental biological process that ensures each daughter cell receives an identical set of chromosomes during cell division. This process requires the coordinated action of cohesin complexes, centromeres, kinetochores, and mitotic kinases to align chromosomes at the metaphase plate and then separate sister chromatids during anaphase. Errors in this process result in aneuploidy, which is associated with cancer, birth defects, and stem cell dysfunction. Understanding the molecular players and regulatory mechanisms of mitotic sister chromatid segregation is therefore critical for both basic cell biology and translational research.
mitotic sister chromatid segregation At A Glance
| GO ID | GO:0000070 |
|---|---|
| GO term | mitotic sister chromatid segregation |
| Ontology | biological_process |
| Synonym | mitotic chromosome segregation; mitotic sister-chromatid adhesion release |
| Major function | Faithful separation of replicated chromosomes into two daughter cells during mitosis |
| Key cellular structures | Cohesin complex, centromere, kinetochore, mitotic spindle |
| Key regulatory proteins | Wapl, separase, Aurora B, Plk1, Cdk1 |
| Associated diseases | Cancer, aneuploidy syndromes, stem cell disorders |
| Research methods | Live-cell imaging, CRISPR knockout, RNA-seq, proteomics |
What Is GO:0000070?
According to the Gene Ontology, GO:0000070 mitotic sister chromatid segregation is defined as the cell cycle process in which replicated homologous chromosomes are organized and then physically separated and apportioned to two sets during the mitotic cell cycle. Each replicated chromosome, composed of two sister chromatids, aligns at the cell equator, paired with its homologous partner. One homolog of each morphologic type goes into each of the resulting chromosome sets. In simpler terms, it is the step-by-step process that ensures each new cell gets a complete and accurate copy of the genome during mitosis.
Why Is mitotic sister chromatid segregation Important in Cell Biology?
Mitotic sister chromatid segregation is essential for maintaining genomic stability across cell divisions. When this process fails, cells can become aneuploid, a condition strongly linked to tumorigenesis and developmental abnormalities. Moreover, emerging evidence shows that biased sister chromatid segregation can influence stem cell fate and tissue homeostasis, making this process relevant to regenerative medicine and aging. Studying GO:0000070 therefore provides insights into fundamental cell biology and multiple human diseases.
• Prevents aneuploidy and maintains genomic integrity during cell division.
• Cohesin mutations are found in Cornelia de Lange syndrome and various cancers.
• Centromere dysfunction can lead to chromosome missegregation and birth defects.
• Asymmetric sister chromatid segregation contributes to stem cell fate decisions.
• Wapl dysregulation affects cohesin dynamics and is implicated in cancer progression.
• Mitotic kinases such as Aurora B are targets for anticancer drug development.
• Understanding segregation mechanisms aids in interpreting cancer genome instability.
• CRISPR screens can identify novel segregation genes and therapeutic targets.
What Happens During mitotic sister chromatid segregation?
Prophase and Prometaphase: Chromosome Condensation and Alignment
In simple terms: The cell prepares by condensing chromosomes and moving them to the center.
During prophase, chromosomes condense and the mitotic spindle begins to form. In prometaphase, sister chromatids attach to spindle microtubules via kinetochores and align at the metaphase plate. Cohesin complexes hold sister chromatids together, while centromere proteins ensure proper attachment.
Metaphase: Bi-orientation and Tension Sensing
In simple terms: Chromosomes line up and the cell checks that each is properly attached.
At metaphase, sister chromatids are bi-oriented, with each kinetochore attached to microtubules from opposite poles. The spindle assembly checkpoint monitors tension and attachment, delaying anaphase until all chromosomes are correctly aligned. Aurora B kinase plays a key role in correcting erroneous attachments.
Anaphase: Cohesin Cleavage and Chromatid Separation
In simple terms: The glue holding sister chromatids is cut, and they are pulled apart.
Anaphase onset is triggered by separase-mediated cleavage of cohesin subunit RAD21, allowing sister chromatids to separate and move to opposite poles. Wapl regulates cohesin release and is critical for timely chromatid separation.
Telophase and Cytokinesis: Nuclear Envelope Reassembly
In simple terms: The cell divides its cytoplasm and forms two new nuclei.
After chromatids reach the poles, nuclear envelopes reassemble around each set, and cytokinesis physically divides the cell. This completes the segregation process and ensures each daughter cell receives a full chromosome complement.
Asymmetric Sister Chromatid Segregation in Stem Cells
In simple terms: Some stem cells deliberately separate old and new DNA strands unequally.
In certain stem cells, sister chromatids are segregated non-randomly, with asymmetric centromere behavior guiding biased segregation. This phenomenon links chromosome segregation to cell fate and tissue maintenance.
Key Genes Involved in GO:0000070 mitotic sister chromatid segregation
The following genes and proteins are central to mitotic sister chromatid segregation, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SMC1A | Core cohesin subunit, holds sister chromatids | Mutations in Cornelia de Lange syndrome; target for segregation studies |
| SMC3 | Core cohesin subunit, ATPase for DNA loop extrusion | Cohesinopathy and cancer research |
| RAD21 | Cohesin subunit cleaved by separase | Essential for anaphase onset; knockout causes cohesion defects |
| STAG1 | Cohesin accessory subunit | Defines cohesin complexes; implicated in cancer |
| STAG2 | Cohesin accessory subunit | Frequently mutated in bladder cancer and glioblastoma |
| WAPL | Releases cohesin from chromatin | Regulates cohesion dynamics; knockout affects chromatid segregation |
| CENPA | Centromere-specific histone H3 variant | Required for kinetochore assembly; key for segregation fidelity |
| CENPB | Centromere protein B, binds CENP-B box | Centromere organization and asymmetric segregation |
| CENPC | Inner kinetochore protein | Links centromere to kinetochore; essential for chromosome alignment |
| AURKA | Mitotic kinase, centrosome maturation | Regulates spindle assembly; target in cancer therapy |
| AURKB | Chromosomal passenger kinase | Corrects kinetochore-microtubule attachments |
| PLK1 | Polo-like kinase 1 | Promotes anaphase onset and cytokinesis |
| SEPARASE | Protease that cleaves cohesin | Triggers sister chromatid separation |
| CDK1 | Cyclin-dependent kinase 1 | Master regulator of mitosis; phosphorylates cohesin and separase |
| BUB1 | Spindle assembly checkpoint kinase | Monitors chromosome bi-orientation |
| MAD2 | Spindle checkpoint protein | Inhibits anaphase until all chromosomes are attached |
| NDC80 | Kinetochore component | Connects centromere to microtubules |
How Is mitotic sister chromatid segregation Regulated?
Mitotic sister chromatid segregation is tightly regulated by phosphorylation and proteolysis. CDK1-cyclin B phosphorylates cohesin and separase, while Aurora B kinase corrects attachment errors. The spindle assembly checkpoint (BUB1, MAD2) delays anaphase until all chromosomes are bi-oriented. Wapl regulates cohesin turnover, and its interaction with cohesin is critical for dynamic chromosome segregation. Additionally, centromere assembly and asymmetric centromere behavior can modulate segregation in stem cells.
mitotic sister chromatid segregation and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| STAG2 | Bladder cancer, glioblastoma | Knockout in cancer cell lines; xenograft models |
| SMC1A | Cornelia de Lange syndrome | Patient-derived iPSCs with point mutations |
| WAPL | Cancer progression, cohesinopathy | Knockout and overexpression in HeLa cells |
| AURKB | Cancer, chromosomal instability | Point mutation (kinase-dead) knock-in |
| CENPA | Centromere dysfunction, aneuploidy | Overexpression and knockout in stem cells |
Cancer and Aneuploidy
Defects in mitotic sister chromatid segregation lead to aneuploidy, a hallmark of many cancers. Mutations in cohesin subunits (STAG2, RAD21) and mitotic kinases (AURKA, AURKB) are found in various tumors, making segregation genes potential therapeutic targets.
Cornelia de Lange Syndrome and Cohesinopathies
Mutations in cohesin complex genes such as SMC1A, SMC3, and RAD21 cause Cornelia de Lange syndrome, a developmental disorder characterized by growth retardation and intellectual disability. These mutations impair sister chromatid cohesion and segregation.
Stem Cell Dysfunction and Aging
Asymmetric sister chromatid segregation is important for stem cell maintenance. Disruption of this process can lead to stem cell exhaustion or biased differentiation, contributing to aging and tissue degeneration.
From mitotic sister chromatid segregation-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does knockout of a candidate gene cause segregation defects? | CRISPR knockout in HeLa or RPE1 cells |
| Does a specific point mutation in cohesin affect sister chromatid cohesion? | CRISPR point mutation knock-in |
| How does a gene fusion affect mitotic progression? | Knock-in of fusion construct |
| Where does a protein localize during mitosis? | Tagged knock-in (e.g., GFP) |
| Does overexpression of a kinase drive aneuploidy? | CRISPR overexpression (dCas9-VP64) |
| Which genes are essential for segregation? | Genome-wide CRISPR library screening |
How to Study the mitotic sister chromatid segregation Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live-cell imaging | Chromosome dynamics and segregation timing | Assessing anaphase onset and lagging chromosomes |
| RNA-seq | Transcriptional changes | Identifying pathways altered by segregation defects |
| Proteomics (Co-IP/MS) | Protein-protein interactions | Mapping cohesin complex interactors |
| CRISPR knockout screening | Gene essentiality for segregation | Discovering novel segregation genes |
| Flow cytometry | DNA content and aneuploidy | Quantifying chromosome missegregation |
| Immunofluorescence | Protein localization and kinetochore structure | Visualizing centromere and spindle components |
| FRAP | Protein dynamics at kinetochores | Measuring cohesin turnover |
| Chromosome spreads | Sister chromatid cohesion | Assessing cohesion defects in mutants |
Live-Cell Imaging
Live-cell imaging with fluorescently tagged histones or centromere proteins allows real-time visualization of chromosome alignment and segregation dynamics. This method is ideal for assessing segregation fidelity and timing.
RNA-Seq and Transcriptomics
RNA sequencing can reveal gene expression changes in cells with segregation defects or after CRISPR knockout of candidate genes. It helps identify pathways affected by aneuploidy.
Proteomics and Co-Immunoprecipitation
Proteomic approaches identify cohesin interactors and post-translational modifications. Co-IP followed by mass spectrometry can map the cohesin interaction network.
CRISPR Library Screening
Genome-wide CRISPR knockout or activation screens can identify genes required for mitotic sister chromatid segregation. Hits are validated by imaging and flow cytometry.
How CRISPR Can Be Used to Study GO:0000070 mitotic sister chromatid segregation
Knockout
CRISPR knockout of genes such as RAD21, STAG2, or WAPL in human cell lines leads to sister chromatid cohesion defects, aneuploidy, and cell cycle arrest. These models are used to study the consequences of losing segregation factors.
Point Mutation
Point mutations in cohesin subunits (e.g., SMC1A, SMC3) identified in Cornelia de Lange syndrome can be introduced via CRISPR to study their effects on sister chromatid segregation and protein function.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) at endogenous loci allows real-time tracking of centromere proteins and cohesin dynamics during mitosis. This approach is valuable for understanding asymmetric segregation in stem cells.
Overexpression
CRISPR activation (dCas9-VP64) or cDNA overexpression can drive high levels of mitotic kinases like AURKB or PLK1, leading to chromosome missegregation and providing models for cancer research.
How EDITGENE Supports mitotic sister chromatid segregation Research
Researchers studying mitotic sister chromatid segregation-related genes often need to determine whether a candidate gene is causally involved in chromosome segregation fidelity, aneuploidy, or stem cell fate. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models for such studies.
Contact EDITGENE today to design your custom CRISPR model for mitotic sister chromatid segregation research.
Frequently Asked Questions About mitotic sister chromatid segregation
What is mitotic sister chromatid segregation?
It is the cell cycle process in which replicated chromosomes are organized and physically separated into two daughter sets during mitosis, ensuring each new cell receives a complete genome.
What genes are involved in mitotic sister chromatid segregation?
Key genes include cohesin subunits (SMC1A, SMC3, RAD21, STAG1/2), centromere proteins (CENPA, CENPB, CENPC), and mitotic kinases (AURKA, AURKB, PLK1).
What is the role of cohesin in sister chromatid segregation?
Cohesin holds sister chromatids together from S phase until anaphase, when it is cleaved by separase to allow chromatid separation.
How does Wapl regulate sister chromatid cohesion?
Wapl promotes cohesin release from chromatin, and its interaction with cohesin is critical for dynamic chromosome segregation.
What happens when sister chromatid segregation fails?
Failure leads to aneuploidy, which is associated with cancer, developmental disorders, and stem cell dysfunction.
What is asymmetric sister chromatid segregation?
It is a phenomenon in some stem cells where sister chromatids are segregated non-randomly, influencing cell fate decisions.
How can I study mitotic sister chromatid segregation in the lab?
Common methods include live-cell imaging, CRISPR knockout, RNA-seq, proteomics, and CRISPR library screening.
Which diseases are linked to mitotic sister chromatid segregation defects?
Cancer, Cornelia de Lange syndrome, and other cohesinopathies are linked to defects in this process.
What is the GO ID for mitotic sister chromatid segregation?
The Gene Ontology ID is GO:0000070.
Can CRISPR be used to model mitotic sister chromatid segregation defects?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used to study segregation genes and their roles in disease.
Conclusion
Mitotic sister chromatid segregation (GO:0000070) is a highly coordinated process essential for genomic stability. Its dysregulation leads to aneuploidy and diseases such as cancer and cohesinopathies. Advances in CRISPR-based models and imaging technologies continue to unravel the molecular mechanisms and regulatory networks governing this process. Targeting segregation factors holds promise for therapeutic intervention in cancer and developmental disorders.
References
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- 3. Carty BL et al.. 2020. Centromere assembly and non-random sister chromatid segregation in stem cells.. Essays Biochem 64(2):223-232 PMID: 32406510
- 4. Zheng G et al.. 2015. Regulation of sister chromatid cohesion during the mitotic cell cycle.. Sci China Life Sci 58(11):1089-98 PMID: 26511516
- 5. Armakolas A et al.. 2010. Discovery of the mitotic selective chromatid segregation phenomenon and its implications for vertebrate development.. Curr Opin Cell Biol 22(1):81-7 PMID: 20022232
- 6. Mogilner A et al.. 2006. Modeling mitosis.. Trends Cell Biol 16(2):88-96 PMID: 16406522
- 7. Yuan X et al.. 2024. Molecular mechanism and functional significance of Wapl interaction with the Cohesin complex.. Proc Natl Acad Sci U S A 121(33):e2405177121 PMID: 39110738
- 8. Ranjan R et al.. 2019. Asymmetric Centromeres Differentially Coordinate with Mitotic Machinery to Ensure Biased Sister Chromatid Segregation in Germline Stem Cells.. Cell Stem Cell 25(5):666-681.e5 PMID: 31564548
