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The naked labelled DNA runs fastest. Reconstitution creates a slower nucleosome band, with a little residual unassembled DNA. Adding NVNA1 progressively generates several additional, more slowly migrating labelled species and reduces the unbound nucleosome population. These are consistent with ternary protein–DNA complexes containing DNA, histones and NVNA1, with increasing occupancy or altered assembly. The naked-DNA titration also shows several NVNA1–DNA species, reflecting different occupancy states on the repeat-containing fragment.

A mobility shift reports changes in charge, size and shape together. It cannot by itself establish that histones remain in every shifted species, or identify exact protein stoichiometries. In particular, similarity to a band in the naked-DNA lanes could indicate histone loss rather than merely another occupancy state. The specific-competitor experiment in the next part supplies the important compositional test: removal of NVNA1 can regenerate a nucleosome band, demonstrating retention of histones in the starting ternary population.