GO:1901673 regulation of mitotic spindle assembly: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1901673 (regulation of mitotic spindle assembly) describes any process that modulates the frequency, rate or extent of mitotic spindle assembly, the microtubule-based machine that segregates chromosomes during mitosis.
• Spindle assembly is controlled by phosphorylation, RanGTP gradients, importin cargo release, and microtubule-associated proteins such as NuMA and TPX2 [1,3,6].
• Spindle orientation and size are actively regulated to ensure accurate chromosome segregation and proper cell division [4,5,8].
• Liquid-liquid phase separation of microtubule-binding proteins is an emerging regulatory layer in spindle assembly.
• Dysregulation of spindle assembly is linked to aneuploidy, cancer, and developmental disorders, making it a key research and therapeutic target [1,4].
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal dissection of spindle regulators in human cells.
Description
The mitotic spindle is a dynamic microtubule-based structure that segregates duplicated chromosomes into daughter cells during mitosis. Its assembly is not a passive process; it is tightly regulated in space and time by a network of kinases, phosphatases, motor proteins, and microtubule-associated proteins. The Gene Ontology term GO:1901673, regulation of mitotic spindle assembly, captures any process that modulates the frequency, rate or extent of this assembly. Understanding this regulation is fundamental to cell biology because errors in spindle assembly lead to chromosome missegregation, aneuploidy, and cell death. Regulation of mitotic spindle assembly integrates multiple inputs, including centrosome maturation, RanGTP-mediated cargo release, Aurora kinase and PLK1 signaling, and spindle assembly checkpoint (SAC) control [1,3,4]. These inputs ensure that the spindle reaches the correct size, orientation, and bipolarity before anaphase onset [5,8]. Recent work has also revealed that liquid-liquid phase separation of microtubule-binding proteins contributes to spindle assembly regulation. For researchers, GO:1901673 provides a precise annotation framework to study how specific genes and mutations alter spindle assembly. This article reviews the definition, molecular mechanisms, key genes, disease links, and experimental models for investigating regulation of mitotic spindle assembly, with a focus on CRISPR-based approaches.
regulation of mitotic spindle assembly At A Glance
| GO ID | GO:1901673 |
|---|---|
| GO term | regulation of mitotic spindle assembly |
| Ontology | biological_process |
| Synonym | regulation of spindle assembly involved in mitosis |
| Major function | Modulates the frequency, rate or extent of mitotic spindle assembly |
| Related processes | Mitotic spindle assembly, spindle assembly checkpoint, spindle orientation, spindle scaling |
| Key regulators | Aurora kinases, PLK1, RanGTP, importins, NuMA, TPX2, motor proteins |
| Disease relevance | Aneuploidy, cancer, developmental disorders |
What Is GO:1901673?
GO:1901673 (regulation of mitotic spindle assembly) is a biological process term defined as any process that modulates the frequency, rate or extent of mitotic spindle assembly. It encompasses positive and negative regulatory inputs that control when, where, and how the mitotic spindle forms, without being the assembly process itself. The synonym 'regulation of spindle assembly involved in mitosis' reflects its mitotic context.
Why Is regulation of mitotic spindle assembly Important in Cell Biology?
Regulation of mitotic spindle assembly is essential for faithful chromosome segregation and genome stability. Defects in this regulation cause aneuploidy, which is a hallmark of cancer and a driver of developmental disorders [1,4]. Moreover, spindle assembly is a validated target for anticancer drugs such as taxanes and Aurora kinase inhibitors. Studying GO:1901673 helps researchers identify causal genes, understand resistance mechanisms, and develop new therapeutic strategies.
• Ensures accurate chromosome segregation and prevents aneuploidy.
• Controls spindle size and scaling in different cell types.
• Integrates with the spindle assembly checkpoint to delay mitosis when needed.
• Regulates spindle orientation, which influences cell fate and tissue architecture.
• Involves phosphorylation cascades that are druggable targets in cancer.
• Phase separation of spindle proteins adds a new layer of regulation.
• Dysregulation is linked to cancer, infertility, and neurodevelopmental disorders [1,4].
• Provides a framework for CRISPR screens to identify novel regulators [1,3].
What Happens During regulation of mitotic spindle assembly?
Initiation and RanGTP gradient
In simple terms: A chemical gradient around chromosomes tells the cell where to build the spindle.
Regulation of mitotic spindle assembly begins with the establishment of a RanGTP gradient around chromosomes, which releases spindle assembly factors such as TPX2 and NuMA from importins [3,6]. This spatial cue ensures that microtubule nucleation and stabilization occur near chromatin. Phosphorylation by Aurora A and PLK1 further activates these factors.
Microtubule nucleation and organization
In simple terms: The cell builds and organizes the protein cables that will pull chromosomes apart.
Microtubule nucleation is regulated by kinases including Aurora A and PLK1, which control centrosome maturation and microtubule stability [1,3]. Motor proteins such as Eg5 and dynein generate forces that organize microtubules into a bipolar spindle. Spindle scaling mechanisms adjust microtubule mass to cell size.
Spindle orientation and positioning
In simple terms: The spindle must point in the right direction to divide cells correctly.
Regulation of spindle orientation involves cortical force generators, LGN, NuMA, and dynein, which couple the spindle to cell polarity cues. This orientation is critical for asymmetric divisions and tissue organization. Phosphorylation of NuMA by Aurora A regulates its cortical localization.
Spindle assembly checkpoint and timing
In simple terms: A safety checkpoint delays division until the spindle is ready.
The spindle assembly checkpoint (SAC) monitors kinetochore-microtubule attachments and delays anaphase until all chromosomes are properly attached. In cells lacking centrosomes, SAC-dependent mitotic delay is required for cell division. This checkpoint is a key regulatory node in GO:1901673.
Phase separation in spindle assembly
In simple terms: Some spindle proteins form liquid droplets that help build the spindle.
Liquid-liquid phase separation of microtubule-binding proteins such as TPX2 and NuMA contributes to spindle assembly regulation by concentrating factors and promoting microtubule nucleation. This emerging mechanism adds a physical layer of regulation to GO:1901673.
Key Genes Involved in GO:1901673 regulation of mitotic spindle assembly
The following genes and proteins are established regulators of mitotic spindle assembly, supported by the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| AURKA | Kinase that regulates centrosome maturation and spindle assembly | Target in cancer; phosphorylates spindle factors |
| PLK1 | Kinase controlling mitotic entry and spindle assembly | Druggable target; regulates microtubule dynamics |
| TPX2 | Spindle assembly factor; activates Aurora A | RanGTP-regulated; phase separation [3,7] |
| NUMA1 | Spindle organizing protein; regulates spindle orientation | Importin-beta cargo; cortical force generation [5,6] |
| RAN | GTPase establishing RanGTP gradient | Controls cargo release near chromosomes |
| KPNB1 | Importin-beta; sequesters spindle factors | Regulates NuMA and TPX2 localization |
| KIF11 | Eg5 kinesin; crosslinks and slides microtubules | Required for bipolar spindle formation |
| DYNC1H1 | Dynein heavy chain; spindle positioning | Cortical force generator |
| LGN | Spindle orientation protein | Links polarity cues to spindle |
| MAD2L1 | Spindle assembly checkpoint protein | Monitors kinetochore attachments |
| BUB1 | Spindle assembly checkpoint kinase | Required for SAC signaling |
| CLASP1 | Microtubule plus-end tracking protein | Regulates microtubule dynamics |
| HAUS complex | Microtubule nucleation and spindle assembly | Augmin complex; regulates spindle assembly |
| CDK1 | Cyclin-dependent kinase; mitotic master regulator | Phosphorylates spindle proteins |
| PPP2CA | Protein phosphatase 2A catalytic subunit | Counteracts mitotic phosphorylations |
| RCC1 | Ran guanine nucleotide exchange factor | Generates RanGTP gradient |
| NEDD1 | Gamma-tubulin ring complex component | Regulates microtubule nucleation |
How Is regulation of mitotic spindle assembly Regulated?
Regulation of mitotic spindle assembly is controlled by reversible phosphorylation, primarily through CDK1, Aurora A, PLK1, and opposing phosphatases such as PP2A. The RanGTP gradient provides spatial regulation by releasing importin-bound spindle factors near chromosomes [3,6]. The spindle assembly checkpoint adds temporal regulation by delaying anaphase until attachments are correct. Additionally, liquid-liquid phase separation of microtubule-binding proteins contributes to the regulation of spindle assembly.
regulation of mitotic spindle assembly and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| AURKA | Cancer; aneuploidy | Knockout and point mutation in cancer cell lines |
| PLK1 | Cancer; mitotic arrest | Knockout and overexpression models |
| NUMA1 | Neurodevelopmental disorders | Knock-in of patient mutations |
| DYNC1H1 | Microcephaly; neuropathy | Knock-in and knockout in neurons |
| MAD2L1 | Cancer; chromosomal instability | Knockout in HCT116 cells |
Cancer and aneuploidy
Dysregulation of mitotic spindle assembly causes chromosome missegregation and aneuploidy, a hallmark of cancer [1,4]. Overexpression of Aurora A and PLK1 is observed in many cancers, and inhibitors are in clinical trials. Targeting spindle assembly regulators is a validated anticancer strategy.
Developmental disorders
Mutations in spindle assembly genes such as NUMA1 and DYNC1H1 are linked to neurodevelopmental disorders and microcephaly. Defects in spindle orientation disrupt asymmetric divisions in neural progenitors.
Infertility and oocyte meiosis
Regulation of spindle assembly is critical in oocyte meiosis, where errors lead to aneuploid eggs and infertility. Meiotic spindle assembly shares regulators with mitosis but has unique features.
From regulation of mitotic spindle assembly-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is AURKA required for spindle assembly? | CRISPR knockout in HeLa cells |
| Does a cancer-associated PLK1 mutation alter spindle assembly? | Point mutation knock-in |
| How does NUMA1 localization change with a tag? | Tagged knock-in (GFP) |
| Does overexpression of TPX2 drive aneuploidy? | Overexpression cell line |
| Which genes regulate spindle assembly in a genome-wide screen? | CRISPR library screening |
| What is the role of phase separation in spindle assembly? | Knock-in of phase separation mutants |
How to Study the regulation of mitotic spindle assembly Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live-cell imaging | Spindle dynamics and chromosome segregation | Assess spindle assembly defects |
| Phosphoproteomics | Phosphorylation changes | Identify kinase substrates |
| CRISPR knockout screen | Gene requirement for spindle assembly | Discover novel regulators |
| RNA-seq | Transcriptional changes | Assess gene expression after perturbation |
| Proximity ligation assay | Protein-protein interactions | Map spindle protein complexes |
| In vitro microtubule assays | Microtubule nucleation and bundling | Test direct regulation |
| Phase separation assays | Droplet formation | Study LLPS of spindle proteins |
Live-cell imaging
Live-cell imaging of fluorescently tagged tubulin and spindle proteins measures spindle assembly dynamics, bipolarity, and chromosome segregation in real time [3,5].
Proteomics and phosphoproteomics
Mass spectrometry identifies phosphorylation changes in spindle regulators upon perturbation, revealing signaling networks.
CRISPR screens
Genome-wide CRISPR knockout screens identify genes that regulate spindle assembly and chromosome segregation [1,3].
In vitro reconstitution
Purified proteins and microtubules reconstitute spindle assembly steps to test sufficiency and mechanism [3,7].
How CRISPR Can Be Used to Study GO:1901673 regulation of mitotic spindle assembly
Knockout
CRISPR knockout of spindle assembly genes such as AURKA or PLK1 causes mitotic arrest and spindle defects, validating their essential roles [1,3]. Knockout cell lines are used to test rescue by wild-type or mutant constructs.
Point Mutation
Point mutation knock-in of cancer-associated mutations in PLK1 or AURKA allows testing of allele-specific effects on spindle assembly. This approach distinguishes driver from passenger mutations.
Knock-in
Tagged knock-in of NUMA1 or TPX2 with fluorescent proteins enables live-cell imaging of spindle assembly dynamics at endogenous expression levels [5,6].
Overexpression
Overexpression of spindle assembly factors such as TPX2 or Aurora A induces spindle abnormalities and aneuploidy, modeling cancer-associated overexpression [1,7].
How EDITGENE Supports regulation of mitotic spindle assembly Research
Researchers studying regulation of mitotic spindle assembly-related genes often need to determine whether a candidate gene is causally involved in spindle assembly, chromosome segregation, or disease. EDITGENE provides CRISPR-based cell models and screening services to enable this causal dissection.
Contact EDITGENE today to design your custom CRISPR model for regulation of mitotic spindle assembly research.
Frequently Asked Questions About regulation of mitotic spindle assembly
What is GO:1901673?
GO:1901673 is the Gene Ontology term for regulation of mitotic spindle assembly, defined as any process that modulates the frequency, rate or extent of mitotic spindle assembly.
What genes are involved in regulation of mitotic spindle assembly?
Key genes include AURKA, PLK1, TPX2, NUMA1, RAN, KPNB1, KIF11, and MAD2L1, among others [1,3,5,6].
How is mitotic spindle assembly regulated?
It is regulated by phosphorylation, RanGTP gradients, importin cargo release, motor proteins, and phase separation [1,3,6,7].
Why is regulation of mitotic spindle assembly important?
It ensures accurate chromosome segregation; defects cause aneuploidy, cancer, and developmental disorders [1,4].
What diseases are linked to spindle assembly defects?
Cancer, aneuploidy, neurodevelopmental disorders, and infertility are linked to spindle assembly defects [1,2,4,5].
What is the role of Aurora A in spindle assembly?
Aurora A is a kinase that regulates centrosome maturation, microtubule nucleation, and spindle assembly.
How does NuMA regulate spindle assembly?
NuMA is a spindle organizing protein regulated by importin-beta and Aurora A, important for spindle orientation [5,6].
What methods study regulation of mitotic spindle assembly?
Live-cell imaging, phosphoproteomics, CRISPR screens, and in vitro reconstitution are common methods [1,3,7].
Can CRISPR be used to study spindle assembly?
Yes, CRISPR knockout, knock-in, and overexpression models are widely used to dissect spindle assembly gene function [1,3].
What is the spindle assembly checkpoint?
The SAC is a surveillance mechanism that delays anaphase until all chromosomes are properly attached to the spindle.
Conclusion
GO:1901673 regulation of mitotic spindle assembly is a central biological process that ensures genome stability. Its molecular mechanisms involve kinases, RanGTP gradients, importins, motor proteins, and phase separation [1,3,6,7]. Dysregulation leads to cancer and developmental disorders, making it a key research area [1,4]. CRISPR-based models from EDITGENE enable causal studies of spindle assembly regulators.
References
- 1. Ong JY et al.. 2020. Phospho-regulation of mitotic spindle assembly.. Cytoskeleton (Hoboken) 77(12):558-578 PMID: 33280275
- 2. Severson AF et al.. 2016. Oocyte Meiotic Spindle Assembly and Function.. Curr Top Dev Biol 116:65-98 PMID: 26970614
- 3. Petry S. 2016. Mechanisms of Mitotic Spindle Assembly.. Annu Rev Biochem 85:659-83 PMID: 27145846
- 4. Farrell KC et al.. 2024. Spindle assembly checkpoint-dependent mitotic delay is required for cell division in absence of centrosomes.. Elife 12 PMID: 39092485
- 5. di Pietro F et al.. 2016. Regulation of mitotic spindle orientation: an integrated view.. EMBO Rep 17(8):1106-30 PMID: 27432284
- 6. Chang CC et al.. 2017. Regulation of mitotic spindle assembly factor NuMA by Importin-β.. J Cell Biol 216(11):3453-3462 PMID: 28939615
- 7. Sun S et al.. 2024. Liquid-liquid phase separation of microtubule-binding proteins in the regulation of spindle assembly.. Cell Prolif 57(10):e13649 PMID: 38736355
- 8. Krüger LK et al.. 2020. Spindle scaling mechanisms.. Essays Biochem 64(2):383-396 PMID: 32501481
