Lab Insights
| Mitosis and Cytokinesis: From Theory to Live-Cell Imaging | |
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관리자
2025-11-28
Introduction In our previous article on the cell cycle(see the full article 👉🏻 Click to view), we outlined how cells move through G1, S, G2, and M. This follow-up focuses on the most visibly dynamic steps: Mitosis and Cytokinesis.
Mitosis segregates duplicated chromosomes into two nuclei, while cytokinesis divides the cytoplasm and cleaves the plasma membrane to produce two daughter cells. These steps are central to growth, tissue repair, and genomic stability. When these processes fail, they can contribute to disease, including cancer.
For the same reason, understanding these processes is crucial for researchers developing anti-mitotic or cytokinesis-modulators. In this post, we walk through each process step by step, explain how control mechanisms and checkpoints coordinate these steps, and share live-cell imaging results of mitotic errors and cytokinesis defects.
Table of Contents 1. Mitosis - Process and Regulation - Observation Example 2. Cytokinesis - Process and Regulation - Observation Example
1. Mitosis Mitosis is the stage that separates duplicated chromosomes into two nuclei. It prepares the cell for cytokinesis, which divides the cytoplasm and completes cell division.
Process and Regulation Mitosis proceeds through five distinct stages—prophase, prometaphase, metaphase, anaphase, and telophase.
Prophase Chromosomes condense while centrosomes separate, initiating the formation of the mitotic spindle.
Prometaphase The nuclear envelope breaks down, and spindle microtubules attach to chromosomes at kinetochores* *Kinetochore: the protein complex at the centromere where spindle microtubules attach Metaphase All chromosomes line up in the middle of the cell so they are ready to be pulled to opposite sides.
Anaphase Sister chromatids separate and move to opposite sides as the spindle pulls on them.
Telophase New nuclear envelops form around each set of chromosomes, the chromosome decondense, and the cell begins cytokinesis.
The spindle assembly checkpoint (SAC) ensures accuracy by monitoring kinetochore–microtubule attachment and tension during prometaphase and metaphase. It keeps the cell at metaphase until all chromosomes are properly attached; only then does anaphase begin. If attachment errors persist, the cell stays arrested and may trigger apoptosis.
For the full checkpoint map, see the previous article 👉🏻 Click to view
This checkpoint can be activated with small molecules such as nocodazole, which disrupt microtubules and arrest cells in prometaphase to study cell-cycle regulation.
Observation Example - Mitosis Arrest
Building on the overview above, the following example shows how disrupting spindle attachment alters mitotic progression.
Control HeLa cells expressing GFP-H2B condense chromosomes, align them at the metaphase plate, and then separate into two nuclei in sequence. Nocodazole-treated cells fail to form proper attachments to spindle fibers, so they remain arrested in metaphase. Over time, some of these cells lose adhesion or undergo apoptosis.
👉🏻 For detailed information, see the Application Notes
Once chromosome are segregated, cytokinesis partitions the cytoplasm and completes cell division.
2.Cytokinesis Cytokinesis is the final process that completes cell division, during which one cell becomes two daughter cells. Below are the key stages involved in this process.
Process and Regulation 
If the ring cannot form or tighten properly, or if material remains trapped between the two sides, the split may be delayed or fail. When this happens, cells can stay connected or become multinucleated.
Observation Example — Cytokinesis Inhibition
With the steps and control conditions above in mind, the example below shows how interfering with the contractile ring alters cell division outcome.
Control HeLa cells expressing tdTomato-actin form a clear contractile ring, the cleavage furrow ingresses, and abscission completes division into two daughter cells. Cytochalasin B–treated cells show impaired ring formation and weak constriction, so the furrow stalls and division does not finish. Some cells remain connected or become multinucleated.
👉🏻 For detailed information, see the Application Notes
In this article, we explored the processes and regulatory mechanisms of Mitosis and Cytokinesis, demonstrating how live-cell imaging makes it possible to observe these events clearly in real time.
The results were obtained using Celloger® Mini Plus and Celloger® Pro, which provide consistent and high-quality imaging data to support research. For more details, please visit our homepage and product page.
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