DNA structure dependent checkpoints as regulators of DNA repair

Checkpoint proteins were initially identified because their loss of function resulted in defects in cell cycle arrest in response to genotoxic treatments. Initially, the analysis of checkpoint pathways concentrated on their function as signal transducers and how the checkpoint signals were communicated to the core cell cycle machinery and transcriptional apparatus. Although some of the early genetic analysis indicated a complex relationship between DNA replication, DNA repair and the checkpoint pathways, it is only now becoming apparent that checkpoint proteins regulate multiple DNA repair and replication functions. Furthermore, recent data suggest that some checkpoint proteins may participate directly in DNA repair events. In this review I summarise the current models for DNA structure-dependent checkpoint activation and review the evidence linking checkpoint proteins both directly and indirectly to DNA repair.