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.
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