Reduction in cell size during development of the spinal cord

Area of Science:

• Developmental biology
• Neuroscience
• Cell biology

Background:

• Spinal cord cells in Xenopus laevis frogs decrease in size during development.
• This size reduction occurs during neural tube formation and continues until metamorphosis.
• Cellular changes in size, number, and shape are not always synchronized.

Purpose of the Study:

• To investigate the mechanisms of spinal cord cell size reduction during Xenopus laevis development.
• To determine the roles of reductive division and cellular atrophy in this process.
• To examine the impact of cell division on catecholaminergic neuron differentiation and size.

Main Methods:

• Blocking cell division using hydroxyurea and aphidicolin (HUA) in embryonic and larval stages.
• Observing changes in spinal cord cell size and differentiation of catecholaminergic neurons.
• Analyzing the interplay between cell division, cell size, and developmental stage.

Main Results:

• Blocking cell division with HUA prevented embryonic cell size reduction but not in larval stages.
• Catecholaminergic neuron differentiation was unaffected by HUA treatment during embryogenesis.
• Both mitotic and postmitotic cells were found to decrease in size during spinal cord development.
• Reductive division is prominent during embryogenesis, while cellular atrophy dominates larval stages.

Conclusions:

• Spinal cord cell size reduction in Xenopus laevis involves at least two mechanisms: reductive division and cellular atrophy.
• These mechanisms operate at different developmental stages, with distinct roles in embryogenesis and larval development.
• Cell size reduction, alongside other regressive events, influences spinal cord morphogenesis and function.