Cell cycle levels in S and at their lowest near mitosis. Cell cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells. In bacteria, which lack a cell nucleus, the cell cycle is divided into the B, C, and D periods. The B period extends from the end of cell division to the beginning of DNA replication. DNA replication occurs during the C period. The D period refers to the stage between the end of DNA replication and
Neuronal cell cycle neurons, which are able to replicate their DNA without neuronal death (Smith et al., 2000). Neurons that are Rb deficient have also been found to re-enter the cell cycle and survive in a 4C DNA state (Lipinski et al., 2001). Duplication of DNA can lead to neuronal diversification in vertebrates, as seen in observations in the developing chick retina. These neurons re-enter the cell cycle as they travel to the ganglion cell layer when they are activated by p75NTR. These neurons are unable to enter mitosis and are stuck in a 4C DNA content state. Cell cycle re-entry by p75NTR