Disordered regions and folded modules in CAF-1 promote histone deposition in S. pombe

Coupling histone deposition with DNA synthesis is important for genome and epigenome integrity in eukaryotes. Here, we reconstituted SpCAF-1, the major histone deposition factor linked to DNA synthesis in fission yeast and characterized its structure using NMR, SAXS and molecular modeling. We reveal the unfolded nature of the acidic domain, and how it folds upon histone binding, while the long KER helix mediates DNA binding and stimulates SpCAF-1 association with the polymerase accessory factor PCNA. By designing specific SpCAF-1 mutants, we demonstrate that both histone and DNA binding are required for its functions in vitro and in vivo. We show that PCNA binding not only accelerates nucleosome assembly in vitro but is also essential for the proper targeting of the complex to the chromatin in vivo. Our structural and functional study reveals how the combination of disordered regions and folded modules in CAF-1 enable the dynamics of multiple interactions to promote histone deposition coupled to DNA synthesis.