Replication-dependent marking of DNA by PCNA facilitates CAF-1-coupled inheritance of chromatin

Chromatin assembly factor 1 (CAF-1) is required for inheritance of epigenet ically determined chromosomal states in vivo and promotes assembly of chrom atin during DNA replication in vitro. Herein, we demonstrate that after DNA replication, replicated, but not unreplicated, DNA is also competent for C AF-1-dependent chromatin assembly. The proliferating cell nuclear antigen ( PCNA), a DNA polymerase clamp, is a component of the replication-dependent marking of DNA for chromatin assembly. The clamp loader, replication factor C (RFC), can reverse this mark by unloading PCNA from the replicated DNA. PCNA binds directly to p150, the largest subunit of CAF-1, and the two prot eins colocalize at sites of DNA replication in cells. We suggest that PCNA and CAF-1 connect DNA replication to chromatin assembly and the inheritance of epigenetic chromosome states.