ABSTRACT
The eukaryotic cell cycle is a cascade of highly complex, sequential, independent, and interdependent events that culminate in the duplication of a cell. The capacity of cells to efficiently sense and respond to environmental stress is central to an organism’s ability to survive and evolve. The analysis of the regulation of DNA-damage inducible genes will shed light on how DNA-damage sensory mechanisms operate and may reveal further connections to the cell-cycle-regulatory machinery. The fact that the late G1 class of genes is expressed immediately after, and is dependent on, the start of the cell cycle suggests that the transacting factors responsible for their expression may be sensing this early control event directly. Cyclins were identified because of their unusual behavior during the cell cycle. Cyclins accumulate during the cell cycle, peaking in abundance at the end of G2. After cells enter mitosis, the cyclins are rapidly destroyed.
