Chromatin assembly factor 1 (CAF-1) is a histone chaperone involved in replication, gene regulation, and DNA repair. CAF-1 transports histones to the replication fork during DNA replication through interactions with proliferating cell nuclear antigen (PCNA) and phosphorylation by the Cdc7-Dbf4 kinase. The study uses budding yeast (Saccharomyces cerevisiae) as a model to understand how CAF-1 phosphorylation regulates its role in gene silencing and DNA damage response. Yeast strains with deleted or mutated CAC1 and CDC7 genes are transformed with plasmids containing mutated CAC1 and a URA3 marker for selection.