Developmental Control of the Cell Cycle: Insights from .

During animal development, a single fertilized egg forms a complete organism with tens to trillions of cells that encompass a large variety of cell types. Cell cycle regulation is therefore at the center of development and needs to be carried out in close coordination with cell differentiation, migration, and death, as well as tissue formation, morphogenesis, and homeostasis. The timing and frequency of cell divisions are controlled by complex combinations of external and cell-intrinsic signals that vary throughout development. Insight into how such controls determine cell division patterns has come from studies in various genetic model systems. The nematode has only about 1000 somatic cells and approximately twice as many germ cells in the adult hermaphrodite. Despite the relatively small number of cells, has diverse tissues, including intestine, nerves, striated and smooth muscle, and skin. is unique as a model organism for studies of the cell cycle because the somatic cell lineage is invariant. Somatic cells divide at set times during development to produce daughter cells that adopt reproducible developmental fates. Studies in have allowed the identification of conserved cell cycle regulators and provided insights into how cell cycle regulation varies between tissues. In this review, we focus on the regulation of the cell cycle in the context of development, with reference to other systems, with the goal of better understanding how cell cycle regulation is linked to animal development in general.