Fig. 8: A model for the association of MORFWH1-WH2 with the nucleosome.

a, b Cryo-EM map (transparent surface representation) of the MORF_WH1-WH2-197 bp nucleosome-scFv complex shows extra density near the nucleosome dyad region (map threshold level at 0.15). DNA and histones of 197 bp chromatosome structure (PDB ID: 7K5X) and MORF_WH2 (green) were docked into the density. The extra density observed on the linker DNA is colored blue. CpGs are colored red and labeled. c A model for the interaction of MORF_WH1-WH2 with the nucleosome. MORF_WH2 (green) is superimposed with H5 (gray) from the structure of NCP₁₆₇ in complex with H5 (PDB ID: 4QLC), and the AF model of MORF_WH1 from UniProt (Q8WYB5) (blue) is superimposed with the crystal structure of the DNA-bound WH from SAMD1 (salmon) (PDB ID 6LUI), as in Fig. 3i. The CpG sequence in the SAMD1-DNA structure is colored green, and the CpG sequence (C22, G23 in a, b) in NCP is colored red. d A zoom-in view of the model shown in c with the secondary structure elements labeled. e EMSA of 197 bp NCP (NCP₁₉₇) in the presence of increasing amounts of indicated WT or mutated His-MORF_WH1. f A model of Cy3-Cy5 labeled NCP₂₇₃ with Cy5 (red circles) positioned at H2AK119C and Cy3 (green circle) positioned at 54 bp from the DNA 5’ end. Histone H1 bound at the dyad is depicted as tan circle. g FRET efficiency of Cy3-Cy5 NCP₂₇₃ upon addition of His-MORF_WH1-WH2. Data represent mean ± SD of at least three separate independent experiments. n≥3 A similar increase in FRET efficiency is observed due to binding of the linker histone H1⁴⁰. Either H1⁴⁰ or His-MORF_WH1-WH2 above 10 nM induce nucleosome self-association, leading to a reduction in the FRET efficiency (Supplementary Fig. 10). Source data are provided as a Source Data file.