Control of G Phase Duration by CDC25B Modulates the Switch from Direct to Indirect Neurogenesis in the Neocortex.

During development, cortical neurons are produced in a temporally regulated sequence from apical progenitors, directly or indirectly, through the production of intermediate basal progenitors. The balance between these major progenitor types is critical for the production of the proper number and types of neurons, and it is thus important to decipher the cellular and molecular cues controlling this equilibrium. Here we address the role of a cell cycle regulator, the CDC25B phosphatase, in this process.

Single-cell imaging of the cell cycle reveals CDC25B-induced heterogeneity of G1 phase length in neural progenitor cells.

Although lengthening of the cell cycle and G1 phase is a generic feature of tissue maturation during development, the underlying mechanism remains poorly understood. Here, we develop a time-lapse imaging strategy to measure the four cell cycle phases in single chick neural progenitor cells in their endogenous environment. We show that neural progenitors are widely heterogeneous with respect to cell cycle length.

Timing the spinal cord development with neural progenitor cells losing their proliferative capacity: a theoretical analysis.

In the developing neural tube in chicken and mammals, neural stem cells proliferate and differentiate according to a stereotyped spatiotemporal pattern. Several actors have been identified in the control of this process, from tissue-scale morphogens patterning to intrinsic determinants in neural progenitor cells. In a previous study (Bonnet et al.

Neurogenic decisions require a cell cycle independent function of the CDC25B phosphatase.

A fundamental issue in developmental biology and in organ homeostasis is understanding the molecular mechanisms governing the balance between stem cell maintenance and differentiation into a specific lineage. Accumulating data suggest that cell cycle dynamics play a major role in the regulation of this balance. Here we show that the G2/M cell cycle regulator CDC25B phosphatase is required in mammals to finely tune neuronal production in the neural tube.