Nuclear crowding and nonlinear diffusion during interkinetic nuclear migration in the zebrafish retina

Area of Science:

• Developmental Biology
• Cell Biology
• Neuroscience

Background:

• Interkinetic nuclear migration is crucial for early neural development.
• The forces driving stochastic nuclear movement in neuroepithelia remain poorly understood.
• Previous studies suggested cell division and apical crowding influence basalward nuclear motion.

Purpose of the Study:

• To investigate the origin of stochastic nuclear movement during interkinetic nuclear migration.
• To test the hypothesis that apical crowding drives basalward nuclear motion.
• To quantify the forces involved in nuclear migration.

Main Methods:

• Long-term, rapid light-sheet and two-photon imaging of zebrafish retinogenesis.
• Tracking of entire nuclear populations within the developing tissue.
• Quantitative analysis using nonlinear diffusion models.

Main Results:

• Observed time-varying nuclear concentration profiles provided clear evidence of crowding.
• Crowding effects were quantitatively described by a nonlinear diffusion model.
• Concentration-dependent stochastic forces within cells, comparable to cytoskeletal transport, explain observed diffusion constants.

Conclusions:

• Apical crowding due to cell division is a key factor in nuclear migration during neuroepithelial development.
• Intracellular forces, influenced by nuclear concentration, govern the stochastic movement of nuclei.
• This study provides a quantitative framework for understanding nuclear dynamics in developing neural tissues.