FACT neither disassembles nor binds properly assembled nucleosomes. FACT neither disassembles nor binds properly assembled nucleosomes. (A) 10 nM nucleosome, reconstituted with labeled H2B on 146 bp of DNA, was incubated with increasing amounts of FACT (10 nM–5 μM) and analyzed by native PAGE. The gel was visualized by SYBR Gold for DNA (left panel), and by H2B fluorescence (right panel). (B) The sedimentation behavior of nucleosomes remains unchanged upon addition of FACT. 130 nM nucleosomes were mixed with 520 nM FACT, and SV-AUC was performed by monitoring absorbance from DNA. Addition of FACT does not increase the S value of the nucleosome. Tao Wang et al. LSA 2018;1:e201800107 © 2018 Wang et al.