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The vesicular compartment of the mitotic apparatus in mammalian cells
Abstract:
Intracellular membranes might play an eminent role in regulating several events during mitosis: In this paper the appearance and changing configurations of the vesicular compartment of the mitotic apparatus of HeLa cells was studied from anaphase to telophase. In early prophase electron opaque and transparent membranous vesicles are found in the pericentriolar region outside the nucleus. During prometaphase when the nuclear envelope opens and starts to disappear, an increasing number of these vesicles appears in the mitotic apparatus near the chromosomes. During metaphase vesicles are spread all over the mitotic apparatus, the number of electron opaque vesicles decreases while the total amount of vesicles does not change significantly. Anaphase shows the same pattern of distribution in the half-spindle and in the midbody. In telophase the amount of electron opaque vesicles increases again. They are now found around vacuoles and near the newly appearing Golgi-cisternae. We assume that the electron opaque vesicles are derived from the Golgi- apparatus which disintegrates during prophase and reappears in late telophase. The change in the appearance of the different types of vesicles during metaphase coincides with drastic changes in the ionic milieu in the mitotic apparatus (Wolniak et al., 1983).
Insights
Intracellular membranes in HeLa cells undergo significant changes during mitosis. Electron-dense vesicles appear to originate from the Golgi apparatus, influencing mitotic events.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Intracellular membranes are crucial for cellular processes.
- The role of vesicular compartments in mitosis is not fully understood.
- HeLa cells provide a model system for studying cell division.
Purpose of the Study:
- To investigate the dynamic changes of vesicular compartments within the mitotic apparatus of HeLa cells.
- To correlate vesicle appearance and configuration with specific mitotic stages (anaphase to telophase).
- To explore the potential origin and function of different vesicle types during mitosis.
Main Methods:
- Time-course electron microscopy of HeLa cells undergoing mitosis.
- Observation and characterization of membranous vesicles in the mitotic apparatus.
- Analysis of vesicle distribution and morphology from prophase to telophase.
Main Results:
- Vesicles are present in the pericentriolar region during prophase, increasing near chromosomes in prometaphase.
- During metaphase, vesicles distribute throughout the mitotic apparatus, with a decrease in electron-opaque types.
- Electron-opaque vesicles reappear in telophase near vacuoles and reforming Golgi cisternae.
Conclusions:
- Electron-opaque vesicles are likely derived from the Golgi apparatus, which disassembles and reforms during mitosis.
- Vesicle dynamics and changes in their populations correlate with distinct mitotic phases.
- These membrane dynamics may be influenced by alterations in the ionic environment of the mitotic apparatus.