| DNA damage or incomplete replication of DNA results in the inhibition of cell cycle progression at the G1 to S or the G2 to M phase transition by conserved regulatory mechanisms known as cell cycle checkpoints. Checkpoint proteins include Rad17, which is involved in regulating cell cycle progression at the G1 checkpoint, and Chk1, Chk2, Rad1, Rad9 and Hus1, which are involved in regulating cell cycle arrest at the G2 checkpoint. Overexpression of Rad17 results in the activation of p53 and an accumulation of cells in G1. Bub1 is involved in cell cycle checkpoint enforcement while Bub2 is part of a checkpoint that prevents premature exit from mitosis and monitors spindle integrity. |
