A defined in vitro system to study ATP-dependent remodeling of short chromatin fibers

ATP-dependent remodeling factors regulate chromatin structure by catalyzing processes such as nucleosome repositioning or conformational changes of nucleosomes. Predominantly, their enzymatic properties have been investigated using mononucleosomal substrates. However, short nucleosomal arrays represent a much better mimic of the physiological chromatin context. Here, we provide a protocol for the enzyme-free reconstitution of regularly spaced nucleosomal arrays. We then explain how these arrays can serve as substrates to monitor ATP-dependent nucleosome movements and changes in the accessibility of nucleosomal DNA.