GO:0007052 mitotic spindle organization: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0007052 mitotic spindle organization is the biological process that assembles, arranges, and disassembles the microtubule spindle during mitosis.
• Spindle organization depends on microtubule motors, crosslinkers, and centrosome-associated proteins that generate and balance forces.
• Key regulators include TACC3, KIF11, KIF23, PLK1, AURKA, TPX2, NUMA1, and RAB11A-positive endosomes.
• Errors in spindle organization cause chromosome missegregation, aneuploidy, and are linked to cancer and oocyte aneuploidy.
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal testing of spindle genes.
• Live-cell imaging, proteomics, and CRISPR library screening are standard methods to study spindle organization.
Description
Mitotic spindle organization (GO:0007052) is a fundamental biological process that ensures the accurate segregation of chromosomes during cell division. The spindle is a dynamic microtubule-based machine that assembles at mitotic entry, captures chromosomes, and segregates sister chromatids before disassembling at mitotic exit. This process is carried out at the cellular level and involves the assembly, arrangement, and disassembly of the microtubule spindle. Researchers study mitotic spindle organization because its failure leads to aneuploidy, a hallmark of cancer and developmental disorders. The spindle is not a static structure; it self-organizes through the concerted action of microtubule motors, crosslinking proteins, and regulatory kinases. For example, the plus-end-directed motor Eg5 (KIF11) is required for spindle pole separation and bipolar spindle formation. In human oocytes, spindle pole organization is uniquely unstable and error-prone, contributing to high rates of aneuploidy. In somatic cells, proteins such as TACC3 regulate spindle assembly and stability by interacting with microtubules and motors. Endosomal trafficking, including Rab11-positive endosomes, also contributes to spindle organization and orientation. Understanding GO:0007052 therefore has broad implications for cancer biology, reproductive medicine, and regenerative medicine.
mitotic spindle organization At A Glance
| GO ID | GO:0007052 |
|---|---|
| GO term | mitotic spindle organization |
| Ontology | biological_process |
| Definition | A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle. |
| Synonym | mitotic spindle organisation; mitotic spindle organization and biogenesis; spindle organization and biogenesis during mitosis; mitotic spindle stabilization |
| Major function | Assembly, arrangement, and disassembly of the microtubule spindle during mitosis |
| Related cellular component | Spindle, spindle pole, centrosome, kinetochore, microtubule |
| Related molecular functions | Microtubule motor activity, microtubule binding, protein kinase activity |
| Key regulators | KIF11, TACC3, PLK1, AURKA, TPX2, NUMA1, RAB11A |
What Is GO:0007052?
GO:0007052 mitotic spindle organization is defined as a process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the microtubule spindle during a mitotic cell cycle. In simpler terms, it covers everything that builds, positions, and eventually takes apart the mitotic spindle. This includes the nucleation of microtubules, the focusing of spindle poles, the attachment of kinetochores to microtubules, and the generation of forces that move chromosomes. The term also encompasses spindle stabilization and the dynamic rearrangements that occur throughout mitosis.
Why Is mitotic spindle organization Important in Cell Biology?
Mitotic spindle organization is essential for faithful chromosome segregation, and its dysfunction is directly linked to aneuploidy, cancer, and infertility. Because the spindle is a self-organizing system, even subtle perturbations in motor proteins or crosslinkers can cause spindle instability and missegregation. Understanding GO:0007052 provides mechanistic insight into how cells maintain genomic stability and offers targets for anticancer drugs that disrupt mitosis.
• Ensures accurate chromosome segregation and genomic stability.
• Prevents aneuploidy, a hallmark of many cancers.
• Spindle assembly checkpoint defects are common in tumor cells.
• Oocyte spindle instability contributes to age-related aneuploidy.
• Spindle proteins are targets for anti-mitotic chemotherapies.
• Endosomal trafficking influences spindle orientation and asymmetric division.
• Plant preprophase band guides spindle orientation in asymmetric division.
• Spindle dynamics are regulated by phosphorylation and motor activity.
• Defects in spindle organization impair development and tissue homeostasis.
• CRISPR screens identify novel spindle assembly factors.
What Happens During mitotic spindle organization?
Spindle assembly and bipolarity establishment
In simple terms: The cell builds a bipolar spindle from microtubules and motors.
During mitotic entry, centrosomes separate and microtubules nucleate to form two asters that mature into spindle poles. The plus-end-directed kinesin Eg5 (KIF11) slides antiparallel microtubules apart, driving centrosome separation and bipolar spindle formation. TACC3, a centrosomal and spindle-associated protein, contributes to spindle assembly and stability by recruiting motors and crosslinkers. In human oocytes, spindle pole organization is uniquely unstable, with acentriolar poles that rely on different mechanisms.
Chromosome capture and congression
In simple terms: Chromosomes attach to spindle microtubules and line up at the center.
Kinetochores on sister chromatids attach to spindle microtubules, and errors are corrected by Aurora B kinase. Chromosomes congress to the metaphase plate through the coordinated action of motors and microtubule depolymerization. The spindle assembly checkpoint monitors attachments and delays anaphase until all chromosomes are properly bi-oriented.
Force generation and spindle stabilization
In simple terms: Motors and crosslinkers generate forces that keep the spindle stable.
Spindle organization relies on a balance of pushing and pulling forces generated by motors such as Eg5, dynein, and kinesins, as well as by microtubule depolymerization. Crosslinking proteins including NuMA and TPX2 contribute to spindle pole focusing and stability. TACC3 is required for spindle stabilization and has been implicated in maintaining spindle integrity under tension.
Endosomal contribution to spindle organization
In simple terms: Membrane vesicles help position the spindle.
Rab11-positive endosomes contribute to mitotic spindle organization and orientation by delivering membranes and signaling molecules to the spindle periphery. This endosomal pathway influences spindle positioning and asymmetric cell division.
Spindle disassembly and mitotic exit
In simple terms: The spindle is taken apart after chromosomes separate.
After anaphase, the spindle disassembles as cells exit mitosis, a process that requires inactivation of mitotic kinases and dephosphorylation of spindle components. Proper disassembly is essential for cytokinesis and for preventing binucleation.
Key Genes Involved in GO:0007052 mitotic spindle organization
The following genes and proteins are central to mitotic spindle organization, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| KIF11 (Eg5) | Plus-end-directed motor; drives centrosome separation and bipolar spindle assembly | Target for anti-mitotic drugs; knockout causes monopolar spindles |
| TACC3 | Spindle assembly and stabilization; recruits motors and crosslinkers | Overexpressed in cancers; regulates spindle integrity |
| PLK1 | Mitotic kinase; regulates spindle assembly, centrosome maturation, and cytokinesis | Inhibitors in clinical trials; key regulator of mitosis |
| AURKA | Kinase; regulates centrosome maturation and spindle assembly | Amplified in cancers; target for inhibitors |
| TPX2 | Microtubule nucleation and spindle pole focusing | Regulates Aurora A; essential for spindle assembly |
| NUMA1 | Spindle pole focusing and crosslinking | Maintains spindle stability; interacts with dynein |
| RAB11A | Endosomal trafficking; contributes to spindle organization and orientation | Links membrane trafficking to spindle positioning |
| DYNC1H1 | Dynein heavy chain; minus-end-directed motor | Required for spindle pole focusing and chromosome movement |
| KIF23 (MKLP1) | Kinesin; central spindle assembly and cytokinesis | Essential for late mitotic events |
| KIF2A | Kinesin; microtubule depolymerization at spindle poles | Regulates spindle length and pole integrity |
| CLASP1 | Microtubule plus-end tracking protein | Regulates spindle microtubule dynamics |
| MAPRE1 (EB1) | Microtubule plus-end tracking protein | Controls spindle positioning and dynamics |
| CDK1 | Cyclin-dependent kinase; master mitotic regulator | Phosphorylates spindle components to drive mitosis |
| CCNB1 | Cyclin B1; activates CDK1 | Regulates mitotic entry and spindle assembly |
| BUB1 | Spindle assembly checkpoint kinase | Monitors kinetochore attachments |
| MAD2L1 | Spindle assembly checkpoint protein | Prevents anaphase until chromosomes are aligned |
| NDC80 | Kinetochore component; microtubule attachment | Essential for chromosome segregation |
| SPDL1 | Spindle pole body component; centrosome integrity | Regulates spindle pole organization |
How Is mitotic spindle organization Regulated?
Mitotic spindle organization is regulated by reversible phosphorylation, primarily through CDK1-cyclin B, Aurora kinases, and Polo-like kinase 1 (PLK1). CDK1 activity peaks at mitosis and phosphorylates spindle components to promote assembly. Aurora A regulates centrosome maturation and spindle assembly, while Aurora B corrects kinetochore-microtubule attachments. PLK1 controls centrosome maturation, bipolar spindle formation, and cytokinesis. Motor proteins such as Eg5 are regulated by phosphorylation, which controls their localization and activity. TACC3 is phosphorylated by Aurora A and other kinases to regulate its spindle function. Endosomal trafficking via Rab11 also modulates spindle orientation in a cell-cycle-dependent manner. Spindle assembly checkpoint proteins, including BUB1 and MAD2L1, provide a surveillance mechanism that delays anaphase until all chromosomes are properly attached.
mitotic spindle organization and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TACC3 | Cancer (overexpression); spindle instability | Knockout and overexpression in cancer cell lines |
| AURKA | Cancer (amplification); mitotic defects | Point mutation and knockout in HeLa or U2OS cells |
| KIF11 | Cancer; monopolar spindle phenotype | Knockout and point mutation in RPE1 cells |
| RAB11A | Cancer; spindle orientation defects | Knockout and knock-in in epithelial cells |
| PLK1 | Cancer; mitotic arrest | Knockout and point mutation in cancer cell lines |
Cancer and aneuploidy
Defects in mitotic spindle organization cause chromosome missegregation and aneuploidy, which are hallmarks of cancer. Overexpression of TACC3 and Aurora A is observed in multiple cancers and correlates with poor prognosis. Anti-mitotic drugs targeting Eg5, Aurora kinases, and PLK1 are in clinical development.
Oocyte aneuploidy and infertility
Human oocytes have a uniquely unstable spindle pole organization, leading to high rates of aneuploidy, especially with advanced maternal age. Understanding spindle organization in oocytes may improve fertility treatments.
Developmental disorders
Mutations in spindle-associated genes can cause microcephaly and other neurodevelopmental disorders due to impaired neural progenitor division. Proper spindle orientation is critical for asymmetric division and tissue architecture.
From mitotic spindle organization-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of TACC3 disrupt spindle assembly? | CRISPR knockout in HeLa cells |
| Does a specific point mutation in KIF11 affect motor activity? | CRISPR point mutation knock-in in RPE1 cells |
| How does Rab11 endosome trafficking affect spindle orientation? | Knock-in of fluorescent Rab11A in epithelial cells |
| Does overexpression of AURKA cause spindle abnormalities? | CRISPR overexpression in cancer cell lines |
| What is the role of PLK1 in spindle assembly? | Knockout and rescue with point mutants |
| How does oocyte spindle organization differ from somatic cells? | Human oocyte models and knockout of spindle genes |
How to Study the mitotic spindle organization Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live-cell imaging | Spindle assembly, dynamics, and chromosome movement | Assessing bipolarity and anaphase onset |
| Immunofluorescence | Spindle morphology, pole number, chromosome alignment | Phenotyping knockout or mutant cells |
| Proteomics | Spindle-associated protein composition | Identifying novel spindle components |
| CRISPR library screening | Genes required for spindle organization | Discovery of new regulators |
| RNA-seq | Transcriptional changes in spindle genes | Evaluating expression after perturbation |
| Phosphoproteomics | Kinase substrates and signaling | Mapping mitotic phosphorylation |
| Electron microscopy | Ultrastructure of spindle poles | Detailed structural analysis |
| FRAP | Microtubule turnover dynamics | Measuring spindle stability |
Live-cell imaging of spindle dynamics
Live-cell imaging with fluorescently tagged tubulin, histones, and spindle proteins allows real-time visualization of spindle assembly, chromosome congression, and anaphase. This method is essential for assessing spindle bipolarity, pole focusing, and dynamics.
Proteomics and interactomics
Mass spectrometry-based proteomics identifies spindle-associated proteins and their post-translational modifications. Affinity purification of spindle components followed by mass spectrometry reveals interaction networks.
CRISPR library screening
Genome-wide CRISPR knockout screens can identify genes required for mitotic spindle organization and chromosome segregation. These screens are powerful for discovering novel spindle regulators.
Fixed-cell immunofluorescence and high-content imaging
Immunofluorescence with antibodies against alpha-tubulin, pericentrin, and kinetochore proteins allows quantification of spindle morphology, pole number, and chromosome alignment. High-content imaging enables large-scale analysis.
How CRISPR Can Be Used to Study GO:0007052 mitotic spindle organization
Knockout
CRISPR knockout of spindle genes such as TACC3, KIF11, or PLK1 causes mitotic arrest, monopolar or multipolar spindles, and chromosome missegregation. Knockout cell lines are valuable for dissecting gene function in spindle organization.
Point Mutation
CRISPR point mutation knock-in allows testing of specific phosphorylation sites or catalytic residues in spindle proteins. For example, mutating the motor domain of KIF11 can reveal its role in spindle assembly.
Knock-in
Knock-in of fluorescent tags (e.g., GFP, mCherry) into endogenous spindle genes enables live-cell imaging of protein localization and dynamics. This approach is ideal for studying Rab11 endosome trafficking during spindle orientation.
Overexpression
CRISPR-mediated overexpression of spindle regulators such as AURKA or TACC3 can mimic cancer-associated overexpression and reveal oncogenic mechanisms. Overexpression models are useful for testing drug sensitivity.
How EDITGENE Supports mitotic spindle organization Research
Researchers studying mitotic spindle organization-related genes often need to determine whether a candidate gene is causally involved in spindle assembly, chromosome segregation, or spindle orientation. 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 mitotic spindle organization research.
Frequently Asked Questions About mitotic spindle organization
What is mitotic spindle organization (GO:0007052)?
GO:0007052 is the biological process that assembles, arranges, and disassembles the microtubule spindle during mitosis.
What genes are involved in mitotic spindle organization?
Key genes include KIF11, TACC3, PLK1, AURKA, TPX2, NUMA1, RAB11A, and many kinesins and dynein subunits.
Why is mitotic spindle organization important for cancer?
Defects in spindle organization cause aneuploidy, a hallmark of cancer, and spindle proteins are targets for anti-mitotic drugs.
How does TACC3 regulate mitotic spindle organization?
TACC3 contributes to spindle assembly and stabilization by recruiting motors and crosslinkers to the spindle.
What is the role of KIF11 (Eg5) in spindle organization?
KIF11 is a plus-end-directed motor that drives centrosome separation and bipolar spindle assembly.
How do Rab11 endosomes contribute to spindle organization?
Rab11-positive endosomes deliver membranes and signaling molecules to the spindle periphery, influencing spindle orientation.
What methods are used to study mitotic spindle organization?
Live-cell imaging, immunofluorescence, proteomics, and CRISPR screens are commonly used.
What happens when mitotic spindle organization fails?
Failure leads to chromosome missegregation, aneuploidy, and cell death or developmental defects.
How is mitotic spindle organization regulated?
It is regulated by CDK1-cyclin B, Aurora kinases, PLK1, and motor protein phosphorylation.
Can CRISPR be used to study mitotic spindle organization?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools for dissecting spindle gene function.
Conclusion
Mitotic spindle organization (GO:0007052) is a dynamic and essential process that ensures accurate chromosome segregation. Its molecular players, including motors, kinases, and endosomal trafficking components, are critical for genomic stability and are implicated in cancer and infertility. Continued research using CRISPR models and advanced imaging will uncover new therapeutic targets and deepen our understanding of cell division.
References
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- 2. Pavin N et al.. 2016. Self-Organization and Forces in the Mitotic Spindle.. Annu Rev Biophys 45:279-98 PMID: 27145873
- 3. Ding ZM et al.. 2017. The role of TACC3 in mitotic spindle organization.. Cytoskeleton (Hoboken) 74(10):369-378 PMID: 28745816
- 4. McIntosh JR. 2016. Mitosis.. Cold Spring Harb Perspect Biol 8(9) PMID: 27587616
- 5. Sawin KE et al.. 1992. Mitotic spindle organization by a plus-end-directed microtubule motor.. Nature 359(6395):540-3 PMID: 1406972
- 6. Hehnly H et al.. 2014. Rab11 endosomes contribute to mitotic spindle organization and orientation.. Dev Cell 28(5):497-507 PMID: 24561039
- 7. Ambrose JC et al.. 2008. Mitotic spindle organization by the preprophase band.. Mol Plant 1(6):950-60 PMID: 19825595
- 8. Fraschini R. 2017. Factors that Control Mitotic Spindle Dynamics.. Adv Exp Med Biol 925:89-101 PMID: 27722958
