UC San Diego

Proper replication and repair of DNA is critical for cell survival and accurate propagation of genetic information. Chromatin assembly and disassembly is required for DNA replication and repair in a healthy cell. There are several chromatin assembly factors, of which chromatin assembly factor-I (CAF-I) and replication-coupling assembly factor (RCAF) are the most studied due to their involvement in both replication and repair. This dissertation utilizes genetic and molecular biology approaches to investigate the joint and separate roles CAF -I and RCAF play during DNA replication and repair, suppression of genomic instability, and checkpoint activation. The dissertation is arranged as follows: Chapter 1 is an introduction to chromatin assembly, focusing specifically on what was known about CAF-I and RCAF prior to the commencement of this research. Chapter 2 reports our findings of the involvement of CAF-I and RCAF in the suppression of gross chromosomal rearrangements and provides a model for the suppression of GCRs through the activation of various checkpoints. Chapter 3 provides evidence for checkpoint activation in CAF-I and RCAF mutants; reports that CAF-I and RCAF mutants are not checkpoint defective; and proposes a model for the action of RCAF at replication forks. Chapter 4 focuses on the role of RCAF (specifically the Asf1 histone chaperone) during post-replication repair by examining genetic interactions between Asf1 and the Rad6-epistasis pathway. Chapter 5 summarizes my finding, discusses their implication to the field and outlines future directions