Centrioles in the cell cycle. I. Epithelial cells

Area of Science:

• Cell Biology
• Cytoskeleton Dynamics
• Centrosome Biology

Background:

• The centrosome, comprising two centrioles, is crucial for cell division and organization.
• Understanding centrosome structure and duplication is key to cell cycle regulation.
• Centrosome maturation and function vary across different cell cycle phases.

Purpose of the Study:

• To elucidate the structural dynamics of the centrosome throughout the cell cycle in pig kidney embryo (PE) cells.
• To detail the ultrastructural differences between mother and daughter centrioles.
• To investigate the formation and role of pericentriolar material and associated microtubules.

Main Methods:

• Electron microscopy was used to examine centrosome structure in nonsynchronous PE cell cultures.
• Detailed observation of centriole morphology and arrangement during different cell cycle stages.
• Analysis of microtubule organization and pericentriolar material association.

Main Results:

• Mother and daughter centrioles exhibit distinct ultrastructures and behaviors during the cell cycle.
• Centriole duplication initiates mid-S phase, with procentriole formation and elongation observed.
• Pericentriolar satellites and halos form and disappear dynamically, correlating with microtubule organization and spindle pole formation.
• Cilium formation occurs on the mother centriole, particularly in G0 phase cells.

Conclusions:

• Centrosome structure is highly dynamic, with distinct centriole roles and maturation processes occurring throughout the cell cycle.
• Centriole duplication and maturation require approximately one and a half cell cycles.
• Centrosome organization is tightly regulated, influencing microtubule dynamics and cell division.