Name: how the mitotic spindle guides cell division
Uploaded: 2025-05-22T09:05:47.000Z
Duration: 2 min 27 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Inheritance and Variation of Traits

3.1.9-12.D

The Mitotic Spindle

Le fuseau mitotique sépare les chromatides sœurs et les déplace vers les côtés opposés de la cellule pendant l’anaphase de la mitose.
Les structures fondamentales du fuseau mitotique sont des cylindres creux appelés microtubules. Deux ensembles de microtubules sont disposés aux extrémités opposées, ou pôles, du fuseau mitotique.
Chaque microtubule a une extrémité négative et une extrémité positive. Les extrémités négatives des microtubules se rejoignent au centre des pôles du fuseau. Les extrémités positives s’étendent vers l’extérieur à partir des pôles.
Il existe différents types de microtubules avec des positions et des rôles distincts dans le fuseau mitose.
Les microtubules kinétochores lient les chromosomes au pôle fusiforme en se fixant à leurs extrémités positives aux kinétochores. Les kinétochores sont de grands complexes protéiques assemblés au niveau du centromère chromatidide, une séquence d’ADN spécialisée qui relie les chromatides sœurs.
La disposition des microtubules interpolaires ressemble à une paire de mains jointes. L’extrémité positive d’un microtubule interpolaire chevauche l’extrémité positive d’un autre microtubule interpolaire s’étendant à partir du pôle opposé. Les protéines motrices s’associent aux microtubules interpolaires pour diriger l’assemblage du fuseau.
Les microtubules astraux ancrent le fuseau dans la cellule. Ces microtubules ressemblent collectivement à une étoile : chaque extrémité positive se projetant vers l’extérieur du pôle du fuseau vers le cortex cellulaire.
Dans la plupart des cellules animales, les microtubules sont organisés autour d’un organite appelé centrosome. Un centrosome est présent à chaque pôle de broche.
Un centrosome est constitué de deux centrioles entourés d’une masse informe de protéines appelée matrice péricentriolaire. Le centrosome produit, organise et ancre les microtubules dans la cellule.
Deux familles de protéines motrices font partie intégrante de la construction et du fonctionnement du fuseau mitotique : les protéines liées à la kinésine et la dynéine. En règle générale, les protéines liées à la kinésine se déplacent vers les extrémités positives des microtubules et la dynéine se déplace vers les extrémités négatives.
La polarité intrinsèque du fuseau mitotique et de ses microtubules facilite la ségrégation mitotique des chromosomes, préparant la cellule à la division.

<ol>
	<li>Heald, Rebecca et Alexey Khodjakov. 2015. « Trente ans de recherche et de capture : la simplicité complexe de l’assemblage du fuseau mitotique. » Le Journal de biologie cellulaire 211 (6) : 1103-11. <a href="https://doi.org/10.1083/jcb.201510015">https://doi.org/10.1083/jcb.201510015</a>.</li>
	<li>Petry, Sabine. 2016. « Mécanismes de l’assemblage du fuseau mitotique. » Revue annuelle de biochimie 85 (1) : 659-83. <a href="https://doi.org/10.1146/annurev-biochem-060815-014528">https://doi.org/10.1146/annurev-biochem-060815-014528</a>.</li>
</ol>

le fuseau mitotique

Le fuseau mitotique – ou appareil à fuseau – est une structure cytosquelettique eucaryote composée de longues fibres protéiques appelées microtubules. Formé lors de la division cellulaire, le fuseau sépare les chromatides sœurs et les déplace vers les extrémités opposées d'une cellule parentale, où les chromosomes désormais individuels sont distribués vers deux noyaux de cellules filles.

La configuration bipolaire du fuseau mitotique facilite la ségrégation chromosomique, préparant la cellule à la division. Un mécanisme qui assure la formation du fuseau mitotique bipolaire repose sur les centrosomes.

Certaines cellules, comme les ovocytes de vertébrés et les cellules végétales supérieures, sont dépourvues de centrosomes ; cependant, la plupart des cellules animales possèdent deux centrosomes lorsqu’elles entrent en mitose. Chaque centrosome s'associe à un arrangement circulaire de microtubules aux extrémités opposées —ou pôles— du fuseau mitotique. En d’autres termes, les centrosomes nucléent les microtubules.

Les protéines motrices— notamment les kinésines et la dynéine— opèrent généralement au niveau ou à proximité des extrémités des microtubules et facilitent la formation du fuseau mitotique bipolaire et la séparation des chromatides sœurs.

Par exemple, les moteurs kinésine-5 situés au niveau de la zone médiane du fuseau s'attachent à et séparent deux microtubules s'étendant à partir des pôles opposés du fuseau ; ce processus favorise la bipolarité et l'allongement du fuseau en éloignant les pôles du fuseau les uns des autres.

On pense que l’activité de la kinésine-5 est contrebalancée par la kinésine-14. Les moteurs Kinesin-14 tirent sur les microtubules s’étendant des pôles opposés, rapprochant ainsi efficacement les pôles. L'activité coordonnée de ces moteurs permet à la broche de s'assembler correctement.

La kinésine-4 et la kinésine-10 sont des chromokinésines, des kinésines qui peuvent s'associer aux chromosomes mitotiques. La kinésine-4 et la kinésine-10 s'associent aux bras chromosomiques, écartant les chromosomes et le pôle du fuseau.

Les dynéines organisent les microtubules dans diverses parties de la cellule. Par exemple, ils relient les microtubules astraux au cytosquelette d’actine, éloignant les pôles du fuseau les uns des autres.

La structure, l'organisation et les composants du fuseau mitotique permettent aux chromatides sœurs de se séparer, préparant ainsi la cellule à une division appropriée.

Le fuseau mitotique

Le fuseau mitotique est une structure cytosquelettique eucaryote composée de longues fibres protéiques appelées microtubules. Formé...

Education

Enseignement

JoVE Core

Cell Biology

Biologie cellulaire

Unit 1

Unité 1

Cell Division

Division cellulaire

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

how the mitotic spindle guides cell division

The mitotic spindle guides chromosome movement during cell division. It is a structure made of microtubules, which are thin protein fibers in the cell. These fibers organize and help separate the genetic material before the cell splits.

The spindle forms as the cell prepares to divide. Its fibers attach to chromosomes and line them up so they can be moved apart in an orderly way. This careful organization helps each new cell receive the correct set of chromosomes.

The mitotic spindle is a key part of mitosis, the process that produces two daughter cells from one parent cell. By directing chromosome separation, it supports accurate cell division in growing and repairing tissues. Understanding the spindle helps explain how cells copy themselves with precision.

How the Mitotic Spindle Guides Cell Division

how-the-mitotic-spindle-guides-cell-division

mitosis and cytokinesis

Stages of Cell Division in Eukaryotes

Cell division in eukaryotes follows a tightly regulated cycle that includes cell growth, DNA replication, chromosome duplication, chromosome distribution to daughter cells, and cell division. Regulatory systems and extracellular signals help control when cells divide. In typical human cells, the cycle takes about 24 hours. The cycle has two major stages. DNA is copied during the S phase of interphase. The mitotic, or M, phase then separates the duplicated chromosomes into two new nuclei and...

chromosome duplication

Chromosome Copying in Cell Division

Chromosome copying is an important step in cell division. Before a cell divides, it must make an exact copy of its chromosomes so each new cell can receive the same genetic information. A chromosome is a DNA-containing structure that carries genes. During duplication, the chromosome is copied into two identical sister chromatids. These copies stay attached until the cell is ready to separate them. This process helps ensure that daughter cells inherit a complete set of chromosomes. Accurate...

cohesins

Cohesins in Sister Chromatid Separation

Cohesins are protein complexes that help hold sister chromatids together after DNA is copied. They play a key role in cell division by keeping the two copies of a chromosome connected until the right time. These proteins act like a link between the sister chromatids. When the cell is ready to separate them, cohesins must be removed or released so each new cell can get one complete set of chromosomes. Cohesins are an important part of chromosome behavior during mitosis and meiosis. Their...

condensins

Condensin Proteins in Chromosome Packing

Condensin proteins help pack DNA into condensed chromosomes during cell division. They are part of the larger set of proteins that organize genetic material so it can be separated correctly when a cell divides. These proteins act by shaping and tightening chromosome structure. This process is important because DNA must be compacted before it can move through the stages of division. Condensins are therefore closely linked to chromosome condensation, the step that makes chromosomes more compact...

the mitotic spindle

The mitotic spindle guides chromosome movement during cell division. It is a structure made of microtubules, which are thin protein fibers in the cell. These fibers organize and help separate the genetic material before the cell splits. The spindle forms as the cell prepares to divide. Its fibers attach to chromosomes and line them up so they can be moved apart in an orderly way. This careful organization helps each new cell receive the correct set of chromosomes. The mitotic spindle is a key...

centrosome duplication

Centrosome Duplication in Cell Division

Centrosome duplication is an important step in cell division. The centrosome helps organize the cell’s internal structure, and it must be copied before a cell divides.

spindle assembly

Spindle Formation in Cell Division

Spindle formation in cell division is the process that builds the microtubule-based spindle needed to separate chromosomes. Microtubules are long protein fibers that help move and organize cell parts during division. During this process, microtubules grow and are arranged into a spindle structure around the chromosomes. The spindle forms in a way that supports chromosome movement to opposite sides of the cell. This step is essential for accurate cell division. Spindle formation depends on the...

attachment of sister chromatids

Sister Chromatid Attachment in Mitosis

Sister chromatid attachment in mitosis helps align duplicated chromosomes before they separate. Sister chromatids are the matching copies made after DNA replication. They stay connected until the cell is ready to divide. The attachment step is closely tied to the metaphase plate, the middle of the cell where chromosomes line up. This alignment helps each new cell receive one copy of every chromosome. Proper attachment is an important part of accurate cell division.

forces acting on chromosomes

Chromosome Movement During Cell Division

Chromosome movement during cell division depends on forces that act on the chromosomes. These forces help move the chromosomes into the right position as the cell divides. The transcript focuses on how these forces affect chromosome behavior during division. It highlights the role of the mitotic spindle, which is the structure that helps organize and move chromosomes. The spindle uses force to guide chromosome movement at the right time. Understanding these forces helps explain how...

separation of sister chromatids

Chromatid Pulling in Cell Division

Separation of sister chromatids is a key step in cell division. Sister chromatids are two identical copies of a chromosome that stay attached until the cell is ready to split them apart. Their separation helps each new cell receive the correct genetic material. During this stage, the sister chromatids are pulled to opposite sides of the cell. This movement happens as the cell prepares to divide into two daughter cells. Once the chromatids separate, each side of the cell has a complete set of...

the spindle assembly checkpoint

How Cells Verify Chromosome Spindle Attachment

The spindle assembly checkpoint helps cells verify that chromosomes are attached to the spindle before division continues. It acts as a safety step during cell division and helps prevent errors in chromosome separation. This checkpoint is controlled by kinetochores, which are protein structures on chromosomes that connect to spindle fibers. If a chromosome is not attached correctly, the checkpoint can delay progression until the problem is fixed. Once the attachment is correct, the cell can...

anaphase a and b

Chromosome and Spindle Movement in Anaphase

Anaphase is the stage of cell division when chromosomes move apart. In this phase, sister chromatids separate and travel toward opposite poles of the cell. Chromosome movement in anaphase can happen in two ways. In anaphase A, chromosomes move closer to the poles as the microtubules attached to them shorten. In anaphase B, the spindle poles themselves move farther apart and help stretch the cell. These two movements work together to ensure that the separated chromosomes are pulled to opposite...

anaphase promoting complex

Cell Cycle Control by APC

The anaphase-promoting complex, or APC, helps control cell cycle progression. It acts during cell division to help move the process from one stage to the next. This control is important for proper timing in the cell cycle. APC is a protein complex that works as a regulator. It helps trigger key steps that allow division to continue in an ordered way. By guiding this transition, APC supports normal cell cycle control.

the contractile ring

Cell Division and the Contractile Ring

The contractile ring helps cells divide at the end of cell division. It forms at the cell's center and tightens to split one cell into two. This process is part of cytokinesis, the stage when the cytoplasm divides. The ring is made of actin and myosin, two proteins that can work together to create force. As the ring contracts, it draws the cell membrane inward. This pinch helps separate the two daughter cells. Understanding the contractile ring is important for studying how cells complete...

determining the plane of cell division

Spindle Position and Cell Division Plane

The plane of cell division is set by the position of the spindle during mitosis. Cells use this internal structure to help decide where the cell will split. The result affects how the two daughter cells are arranged after division. This process is important in many developing tissues. It helps explain how cells divide in a controlled direction. A clear plane of division supports proper cell organization as new cells form. The transcript focuses on how the spindle is used to determine that...

the phragmoplast

Phragmoplast in Plant Cell Division

The phragmoplast is a plant cell structure that forms during cell division. It helps guide the final stage of division, when the cell begins to split into two daughter cells. In plant cells, the phragmoplast appears between the two new nuclei. It is part of the process that leads to the formation of a new cell wall. This wall separates the daughter cells after division is complete. The phragmoplast plays an important role in plant cytokinesis, which is the physical division of the cytoplasm.

distribution of cytoplasmic content

Cytoplasmic Content During Cell Division

Cytoplasmic content is distributed as a cell divides. This process helps each new cell receive the materials it needs to function. The cytoplasm includes the fluid and structures inside the cell membrane, but outside the nucleus. During cell division, this content is separated between the two daughter cells. The division must be organized so both cells can continue normal activity after the split. The video focuses on how this distribution occurs as part of cell division. It highlights the...

key terms and concepts

Learn how the mitotic spindle uses microtubules to line up and separate chromosomes during mitosis so each daughter cell gets the right genetic material.

How the Mitotic Spindle Guides Cell Division | JoVE K12

cell biology

JoVE Core Biologie cellulaire illustre les processus cellulaires complexes dans des leçons vidéos complètes mais faciles à comprendre. Cette collection se concentre sur les composants et fonctions essentiels de la cellule ; cela inclut les organelles et les membranes ainsi que le transport et le métabolisme énergétique cellulaire. Elle est complétée par nos vidéos de scientifiques à l'action qui démontrent l'application de la biologie cellulaire dans des expériences concrètes.

Louisiana Student Standards for Science

High School

Life Sciences

from-molecules-to-organisms-structures-and-processes

From Molecules To Organisms: Structures And Processes

HS-LS1-4

Tennessee Academic Standards

Biology

From Molecules to Organisms: Structures and Processes

BIO1.LS1.6

Minnesota Academic Standards in Science

3.1.1 9L.3.1.1.2

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New Jersey Student Learning Standards for Science

Arizona Science Standards

HS+B.L1

HS+B.L1U1.9

Alabama Course of Study Science

9-12.B.1.3

Next Generation Science Standards

Florida Department of Education

SC.912.L.16

SC.912.L.16.14

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

B-LS1-4.

new-york-state-science-learning-standards

New York State Science Learning Standards

HS-LS1-4.

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3.1.9-12.Q

How the Mitotic Spindle Guides Cell Division

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