Figure 7. A model for the functions of ATP-driven nucleosome assembly and remodeling activities in the assembly of chromatin.
In this model, nucleosomes can be assembled by an ATP-dependent motor protein in the essentially complete absence of chromatin remodeling activity, as seen with the mutant Chd1 proteins. The resulting nucleosomes are, however, randomly distributed throughout the DNA template. These randomly-distributed nucleosomes can be converted into periodic nucleosome arrays by an ATP-dependent nucleosome remodeling (spacing) activity that can be distinguished from the chromatin assembly activity. These processes may occur concurrently with the wild-type Chd1.