Extinguishing a Cell Cycle Checkpoint

摘要

The steps in cell division are precisely orchestrated. A key checkpoint is inactivated after it has performed its function so that the next steps can take place. The faithful ordering of the events that accomplish the division of a eukaryotic cell isenforced by checkpoints, mechanisms that block the initiation of key events until an upstream event has been successfully completed. A well-studied example is the spindle checkpoint, which prevents the mitotic spindle from segregating replicated chromosomes into progeny nuclei until all the chromosomes have achieved proper attachment to spindle fibers (1). Cells defective for spindle checkpoint genes segregate chromosomes with reduced fidelity, causing aneuploidy, a hallmark of many cancer cells (2).