Neuronal specification exploits the inherent flexibility of cell-cycle gap phases

Area of Science:

• Developmental Biology
• Computational Biology
• Cell Biology

Background:

• Pluripotent stem cells differentiate into specialized cell types during organogenesis.
• This process involves a spatiotemporal coupling between cell-cycle progression and differentiation.
• Understanding this coupling is crucial for developmental biology.

Purpose of the Study:

• To computationally model neurogenesis and explore the role of specific factors in cell-cycle progression and differentiation.
• To investigate how the interplay between Neurog2, Hes1, and G1-phase regulators influences cell fate decisions.

Main Methods:

• Computational modeling of neurogenesis.
• Analysis of gene regulatory networks involving Neurog2, Hes1, and cell-cycle regulators.
• Simulation of cell-cycle dynamics and differentiation pathways.

Main Results:

• Accumulating Neurog2 and CKI (Cyclin-dependent kinase inhibitor) enables precise control of G1-phase lengthening, linking it to terminal differentiation.
• Hes1 promotes early-G1 cell-cycle arrest, and its oscillations, along with lateral inhibition, maintain a balance between proliferation and differentiation.
• This balance allows cells to choose between self-renewal and differentiation.

Conclusions:

• Developmental fate decisions leverage the flexibility of cell-cycle gap phases.
• Specific patterns of connections within cell-cycle and differentiation pathways generate cellular diversity.
• This mechanism is relevant for Ascl1-dependent neural differentiation.