Mechanisms of ATP-dependent nucleosome sliding

Chromatin remodelers are multifunctional protein machines that use a conserved ATPase motor to slide nucleosomes along DNA. Nucleosome sliding has been proposed to occur through two mechanisms: twist diffusion and loop/bulge propagation. A central idea for both of these models is that a DNA distortion propagates over the surface of the nucleosome. Recent data from biochemical and single-molecule experiments have expanded our understanding of histone–DNA and remodeler–nucleosome interactions, and called into question some of the basic assumptions on which these models were originally based. Advantages and challenges of several nucleosome sliding models are discussed.