The synergy between RSC， Nap1 and adjacent nucleosome in nucleosome remodeling.

Eukaryotes have evolved a specific strategy to package DNA. The nucleosome is a 147-base-pair DNA segment wrapped around histone core proteins that plays important roles regulating DNA-dependent biosynthesis and gene expression. Chromatin remodeling complexes (RSC， Remodel the Structure of Chromatin) hydrolyze ATP to perturb DNA-histone contacts， leading to nucleosome sliding and ejection. Here， we utilized tethered particle motion (TPM) experiments to investigate the mechanism of RSC-mediated nucleosome remodeling in detail. We observed ATP-dependent RSC-mediated DNA looping and nucleosome ejection along individual mononucleosomes and dinucleosomes. We found that nucleosome assembly protein 1 (Nap1) enhanced RSC-mediated nucleosome ejection in a two-step disassembly manner from dinucleosomes but not from mononucleosomes. Based on this work， we provide an entire reaction scheme for the RSC-mediated nucleosome remodeling process that includes DNA looping， nucleosome ejection， the influence of adjacent nucleosomes， and the coordinated action between Nap1 and RSC.