Potential Rotation Projects

1) Coordination of replication and recombination by the S-phase DNA damage checkpoint

The replication checkpoint coordinates replication and recombinational repair to allow for the replication of damaged templates, however the mechanism by which the checkpoint regulates recombination is unknown. We have identified a number of potential checkpoint-kinase targets by phosphoproteomics. One possible rotation project would be to create site-directed mutations that would prevent kinase regulation of one or more of the targets. These mutations could be used to validate the role of the target in the checkpoint and to test the importance of checkpoint regulation in S-phase DNA repair.

2) Regulation of replication timing

Heterochromatin regulates the timing of replication origin firing, however the mechanism by which it affects origin function is unknown. We have developed a model of how origin timing is regulated in non-heterochromatic chromatin; now we want to test how heterochromatin affects this mechanism. In particular, we want to manipulate the heterochromatic context at specific loci, measure the changes in origin timing and investigate the molecular mechanisms responsible for the change. One possible rotation project would be to establish heterochromatin at a well-characterized origin, measure origin timing, which we presume will be delayed, and then test at which step origin firing is delayed.