Roles of RecQ Family Helicases in the Maintenance of Genome Stability

The maintenance of genome stability is essential in allorganisms for cell survival, and loss of genome integrityin multicellular organisms can give rise to cancer. Cellshave therefore evolved multiple mechanisms to ensurethat genome integrity is maintained. In addition to pathways that recognize and directly repair damaged DNA(for review, see Sancar 1996; Wood 1996; Karran 2000),mechanisms exist that must coordinate the actions of thecellular repair machinery with other nuclear events suchas DNA replication and chromosome segregation. Cellcycle checkpoints fulfill a major role in this respect by arresting the cell cycle in response to DNA damage at astage prior to, for example, the initiation of S phase or mitosis (for review, see Weinert 1998; Caspari and Carr1999). However, in cells that have traversed through apoint in the cell cycle where a checkpoint can be activated, it is essential that the DNA repair machinery interfaces with normal events of the cell cycle in such a wayas to ensure the accurate removal of any DNA damage.Otherwise, lesions may remain unrepaired and even giverise to further genome destabilization in subsequent cellcycles...