Figure 3.

Protein abundance is dynamic during neurogenesis. Neural stem cells are characterized by slow, symmetric cell division. As they progress through neurogenesis and proneural proteins are expressed, the plane of divisions is changed and they divide asymmetrically generating a neural stem daughter cell and neuronal progenitor daughter cell. The cell (orange) that accumulates gene products required for neuronal differentiation exits the cell cycle and differentiates into a neuron. During neurogenesis, the complementary oscillation of Hes1 and Ngn is lost. The factors that maintain neural progenitors (SoxB1, Notch, REST) are degraded. Delta and Ngn are stabilized transiently to allow time for Ngn to induce target genes such as neuroD and the regulators of cell cycle exit.