The ins and outs of nucleosome assembly.

De novo nucleosome assembly coupled to DNA replication and repair in vitro involves the histone chaperone chromatin assembly factor 1 (CAF-1). Recent studies support a model in which CAF-1 can be targeted to newly synthesized DNA through a direct interaction with proliferating cell nuclear antigen (PCNA) and can act synergistically with a newly identified histone chaperone. Insights have also been obtained into mechanisms by which this CAF-1-dependent pathway can establish a repressed chromatin state.