GO:0099607 lateral attachment of mitotic spindle microtubules to kinetochore: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0099607 describes the lateral attachment of sister chromatids to spindle microtubules during mitotic metaphase plate congression, a step that precedes end-on attachment and chromosome migration to the spindle equator.
• Lateral attachment is enriched in prometaphase rosette configurations and facilitates chromosome alignment and bi-orientation establishment.
• The kinetochore-microtubule interface involves a network of proteins including NDC80 complex, SKA complex, and dynein, which mediate initial lateral contacts before converting to end-on attachments.
• EB1 decoration of the microtubule lattice promotes lateral attachment, as shown in Plasmodium male gametogenesis, highlighting an evolutionarily conserved mechanism.
• Microtubule pivoting around the spindle pole accelerates kinetochore capture, a process that can lead to lateral attachment before full bipolar orientation.
• Defects in lateral attachment can lead to chromosome misalignment, aneuploidy, and are implicated in cancer and developmental disorders.
Description
The accurate segregation of genetic material during mitosis depends on the precise attachment of spindle microtubules to kinetochores. GO:0099607, lateral attachment of mitotic spindle microtubules to kinetochore, defines a critical early step in this process where sister chromatids become laterally attached to the sides of microtubules during metaphase plate congression. This lateral interaction is distinct from the subsequent end-on attachment that ultimately pulls chromosomes to the spindle poles. Understanding this process is essential for researchers studying chromosome instability, cell division, and related diseases such as cancer. Lateral attachment is particularly prominent in prometaphase rosette structures, where chromosomes are arranged around the spindle pole, and it facilitates the establishment of bi-orientation. The kinetochore-microtubule interface is a highly dynamic structure, and lateral attachment represents a key intermediate state that allows for error correction and proper chromosome alignment. This article synthesizes current knowledge on the molecular players, regulatory mechanisms, and experimental approaches to study GO:0099607, providing a resource for biomedical researchers.
lateral attachment of mitotic spindle microtubules to kinetochore At A Glance
| GO ID | GO:0099607 |
|---|---|
| GO term | lateral attachment of mitotic spindle microtubules to kinetochore |
| Ontology | biological_process |
| Synonym | None |
| Major function | Initial lateral binding of kinetochores to microtubule sides during prometaphase, facilitating chromosome congression and bi-orientation |
| Related cellular component | Kinetochore, spindle microtubules, prometaphase rosette |
| Related molecular function | Microtubule binding, kinetochore-microtubule attachment |
| Pathological relevance | Chromosome missegregation, aneuploidy, cancer |
What Is GO:0099607?
GO:0099607 is a biological process term describing the cellular process in which sister chromatids become laterally attached to spindle microtubules as part of mitotic metaphase plate congression. This attachment occurs before the chromosomes migrate along microtubules towards the spindle equator (metaphase plate). In simpler terms, it is the initial side-on connection between chromosomes and the microtubule spindle that helps them get ready to align properly before being pulled apart.
Why Is lateral attachment of mitotic spindle microtubules to kinetochore Important in Cell Biology?
Lateral attachment of mitotic spindle microtubules to kinetochores is a fundamental step in mitosis because it ensures that chromosomes are properly positioned before they are segregated. Errors in this process can lead to chromosome misalignment, aneuploidy, and genomic instability, which are hallmarks of cancer and developmental disorders. Studying GO:0099607 provides insights into the mechanisms of chromosome congression and the error-correction machinery that safeguards genome integrity.
• Lateral attachment is a prerequisite for efficient chromosome congression and bi-orientation establishment.
• It is enriched in prometaphase rosettes, which are transient structures that facilitate rapid chromosome capture.
• Defects in lateral attachment can cause chromosome misalignment and aneuploidy, contributing to tumorigenesis.
• The process is regulated by Aurora B kinase, which phosphorylates kinetochore substrates to correct erroneous attachments.
• EB1-mediated microtubule lattice decoration promotes lateral attachment, as shown in Plasmodium, suggesting conserved mechanisms.
• Microtubule pivoting around the spindle pole accelerates kinetochore capture and may lead to lateral attachment.
• Understanding lateral attachment can inform therapeutic strategies targeting mitotic kinases in cancer.
• It is a key area of research for understanding cell division in diverse organisms, from humans to parasites.
What Happens During lateral attachment of mitotic spindle microtubules to kinetochore?
Initial Kinetochore Capture by Microtubules
In simple terms: The kinetochore first grabs onto the side of a microtubule.
During prometaphase, kinetochores are initially captured by the lateral surface of spindle microtubules. This lateral attachment is mediated by the NDC80 complex and other kinetochore proteins that bind to the microtubule lattice. In many cell types, this occurs within a rosette structure where chromosomes surround the spindle pole, allowing for efficient capture. Microtubule pivoting around the spindle pole can accelerate this capture process.
Formation of Prometaphase Rosette
In simple terms: Chromosomes cluster around the spindle pole in a flower-like arrangement.
The prometaphase rosette is a transient configuration where sister chromatids are laterally attached to microtubules emanating from a single pole. This arrangement is enriched in lateral attachments and facilitates the subsequent establishment of bi-orientation. The rosette helps to bring chromosomes close to the spindle equator for proper alignment.
Transition to End-on Attachment
In simple terms: The side attachment converts to a tip attachment.
Lateral attachments are gradually replaced by end-on attachments, where microtubules insert into the kinetochore's outer plate. This transition is crucial for chromosome congression and requires the coordinated action of proteins such as dynein and the SKA complex. The conversion is regulated by Aurora B kinase, which phosphorylates substrates to destabilize incorrect attachments.
Chromosome Congression to Metaphase Plate
In simple terms: Chromosomes move to the center of the cell.
Once lateral attachments are established, chromosomes migrate along microtubules towards the spindle equator. This movement is driven by microtubule depolymerization and motor proteins, and it ensures that chromosomes align at the metaphase plate before anaphase. Lateral attachment facilitates this congression by providing an initial connection that can be rapidly remodeled.
Key Genes Involved in GO:0099607 lateral attachment of mitotic spindle microtubules to kinetochore
The following genes and proteins are key players in the lateral attachment of mitotic spindle microtubules to kinetochores, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NDC80 | Core kinetochore component that binds microtubules | Essential for lateral and end-on attachment; knockout causes chromosome misalignment |
| NUF2 | Part of NDC80 complex, mediates microtubule binding | Mutations affect kinetochore-microtubule attachment |
| SPC24 | NDC80 complex subunit | Required for stable kinetochore-microtubule interactions |
| SPC25 | NDC80 complex subunit | Involved in initial lateral attachment |
| SKA1 | SKA complex, links kinetochore to microtubules | Facilitates lateral-to-end-on conversion |
| SKA2 | SKA complex subunit | Important for chromosome congression |
| SKA3 | SKA complex subunit | Regulates attachment stability |
| Dynein | Minus-end directed motor | Mediates lateral attachment and chromosome movement |
| Aurora B | Mitotic kinase | Phosphorylates kinetochore substrates to correct attachments |
| BubR1 | Spindle checkpoint protein | Acetylation by Aurora B regulates checkpoint control |
| EB1 | Microtubule plus-end tracking protein | Decorates microtubule lattice to promote lateral attachment |
| CLASP | Microtubule stabilizer | Regulates microtubule dynamics during attachment |
| KIF18A | Kinesin motor | Controls chromosome congression |
| CENP-E | Kinesin motor | Facilitates chromosome alignment |
| MAD1 | Spindle checkpoint protein | Monitors attachment status |
| MAD2 | Spindle checkpoint protein | Inhibits anaphase until attachments are correct |
| PLK1 | Polo-like kinase | Regulates kinetochore-microtubule attachment |
| CDK1 | Cyclin-dependent kinase | Controls mitotic progression |
How Is lateral attachment of mitotic spindle microtubules to kinetochore Regulated?
Lateral attachment is regulated by Aurora B kinase, which phosphorylates kinetochore substrates such as BubR1 to control attachment stability and checkpoint signaling. The spindle assembly checkpoint monitors attachment status and delays anaphase until all chromosomes are properly bi-oriented. Additionally, microtubule dynamics and post-translational modifications of tubulin, such as detyrosination, influence lateral attachment efficiency.
lateral attachment of mitotic spindle microtubules to kinetochore and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Aurora B | Cancer, chromosomal instability | Knockout or point mutation in cancer cell lines |
| NDC80 | Aneuploidy, developmental defects | Knockout in human cells |
| BubR1 | Mosaic variegated aneuploidy | Knock-in of acetylation mutants |
| EB1 | Malaria transmission | Knockout in Plasmodium |
| SKA1 | Cancer | Overexpression in tumor models |
Cancer and Aneuploidy
Defects in lateral attachment can lead to chromosome missegregation and aneuploidy, which are common features of cancer cells. Overexpression of Aurora B and other mitotic kinases is observed in many tumors, and targeting these proteins is a therapeutic strategy. Mutations in kinetochore genes such as NDC80 can cause chromosomal instability.
Developmental Disorders
Proper chromosome segregation is essential for development. Mutations in genes involved in lateral attachment, such as those encoding NDC80 complex components, can cause developmental abnormalities and are associated with conditions like microcephaly.
Parasitic Infections
In Plasmodium, EB1-mediated lateral attachment is crucial for male gametogenesis. Understanding this process may inform strategies to block malaria transmission.
From lateral attachment of mitotic spindle microtubules to kinetochore-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of NDC80 in lateral attachment? | Knockout cell line |
| How does Aurora B phosphorylation regulate attachment? | Point mutation (phospho-deficient) knock-in |
| Can EB1 overexpression enhance lateral attachment? | Overexpression cell line |
| What is the dynamics of lateral attachment in live cells? | Tagged knock-in (e.g., GFP-NDC80) |
| Which genes are essential for chromosome congression? | CRISPR library screening |
| How does BubR1 acetylation affect checkpoint control? | Knock-in of acetylation mimics |
How to Study the lateral attachment of mitotic spindle microtubules to kinetochore Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live-cell imaging | Dynamics of kinetochore-microtubule attachment | Visualizing lateral attachment in real time |
| CRISPR knockout | Gene function in attachment | Identifying essential genes |
| RNAi | Gene knockdown effects | Transient depletion studies |
| Proteomics | Protein interactions and modifications | Mapping kinetochore network |
| Phosphoproteomics | Kinase substrate identification | Aurora B targets |
| In vitro reconstitution | Minimal components for attachment | Mechanistic dissection |
| Electron microscopy | Ultrastructure of kinetochore-microtubule interface | High-resolution structural analysis |
Live-cell Imaging
Live-cell imaging with fluorescently tagged kinetochore and microtubule markers allows real-time visualization of lateral attachment dynamics and chromosome congression.
RNA Interference and CRISPR Knockout
RNAi or CRISPR knockout of candidate genes can reveal their roles in lateral attachment. For example, NDC80 depletion results in defective attachment.
Proteomics and Phosphoproteomics
Mass spectrometry-based proteomics can identify post-translational modifications and protein interactions at the kinetochore during lateral attachment.
In Vitro Reconstitution
In vitro assays using purified kinetochore proteins and microtubules can dissect the molecular requirements for lateral attachment.
How CRISPR Can Be Used to Study GO:0099607 lateral attachment of mitotic spindle microtubules to kinetochore
Knockout
CRISPR knockout of genes such as NDC80, SKA1, or Aurora B can abolish lateral attachment, leading to chromosome misalignment and mitotic arrest. These models are valuable for studying the essentiality of each component.
Point Mutation
Point mutations can be introduced to mimic phosphorylation or acetylation states. For example, BubR1 acetylation mutants can be generated to study checkpoint control.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) into endogenous loci allows visualization of protein localization and dynamics during lateral attachment.
Overexpression
Overexpression of EB1 or other microtubule regulators can enhance lateral attachment and alter chromosome congression, providing insights into gain-of-function mechanisms.
How EDITGENE Supports lateral attachment of mitotic spindle microtubules to kinetochore Research
Researchers studying lateral attachment of mitotic spindle microtubules to kinetochore-related genes often need to determine whether a candidate gene is causally involved in this process or merely correlated with it. EDITGENE provides a comprehensive suite of CRISPR-based services to enable such functional studies.
Contact EDITGENE today to design your custom CRISPR model for lateral attachment of mitotic spindle microtubules to kinetochore research.
Frequently Asked Questions About lateral attachment of mitotic spindle microtubules to kinetochore
What is GO:0099607?
GO:0099607 is a Gene Ontology term for the biological process of lateral attachment of mitotic spindle microtubules to kinetochore, where sister chromatids initially bind to the sides of microtubules during metaphase plate congression.
What genes are involved in lateral attachment of mitotic spindle microtubules to kinetochore?
Key genes include NDC80, NUF2, SPC24, SPC25, SKA1, SKA2, SKA3, dynein, Aurora B, BubR1, and EB1.
Why is lateral attachment important for mitosis?
Lateral attachment is crucial for chromosome congression and bi-orientation, ensuring proper chromosome segregation and genomic stability.
How is lateral attachment regulated?
It is regulated by Aurora B kinase, which phosphorylates kinetochore substrates, and by the spindle assembly checkpoint.
What diseases are associated with defects in lateral attachment?
Defects can lead to aneuploidy, cancer, and developmental disorders.
What methods are used to study lateral attachment?
Live-cell imaging, CRISPR knockout, RNAi, proteomics, and in vitro reconstitution are commonly used.
What is the role of EB1 in lateral attachment?
EB1 decorates the microtubule lattice to promote lateral attachment, as shown in Plasmodium male gametogenesis.
How does Aurora B affect lateral attachment?
Aurora B phosphorylates kinetochore proteins to destabilize incorrect attachments and promote proper bi-orientation.
What is a prometaphase rosette?
A prometaphase rosette is a transient structure where chromosomes are laterally attached to microtubules around the spindle pole, facilitating alignment.
Can CRISPR be used to study lateral attachment?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect gene function in lateral attachment.
Conclusion
Lateral attachment of mitotic spindle microtubules to kinetochores (GO:0099607) is a critical early step in mitosis that ensures proper chromosome congression and segregation. Research into its molecular mechanisms has revealed key roles for the NDC80 complex, SKA complex, Aurora B kinase, and EB1. Understanding this process is essential for uncovering the causes of aneuploidy and cancer, and for developing targeted therapies. EDITGENE provides comprehensive CRISPR services to facilitate functional studies of genes involved in this process.
References
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- 4. Monda JK et al.. 2018. The kinetochore-microtubule interface at a glance.. J Cell Sci 131(16) PMID: 30115751
- 5. Matković J et al.. 2022. Kinetochore- and chromosome-driven transition of microtubules into bundles promotes spindle assembly.. Nat Commun 13(1):7307 PMID: 36435852
- 6. Choi SY et al.. 2026. Linking kinetochore attachment to checkpoint control: the role of Aurora B in BubR1 acetylation.. Nucleic Acids Res 54(2) PMID: 41533580
- 7. Kalinina I et al.. 2013. Pivoting of microtubules around the spindle pole accelerates kinetochore capture.. Nat Cell Biol 15(1):82-7 PMID: 23222841
- 8. Itoh G et al.. 2018. Lateral attachment of kinetochores to microtubules is enriched in prometaphase rosette and facilitates chromosome alignment and bi-orientation establishment.. Sci Rep 8(1):3888 PMID: 29497093
