Fig. 3: Tau can compact open chromatin under low salt conditions.
From: Phosphorylation regulates tau’s phase separation behavior and interactions with chromatin
a TEM images and schematic of cation-induced compaction of 12mer arrays (11.3 nM of 12mer array which is equivalent to 136 nM of mononucleosomes) with MgCl2, as compaction control, and increasing concentrations of tau (0.136 μM and 1.36 μM), conducted in 20 mM HEPES buffer, 10 mM NaCl, 0.5 mM TCEP, pH 7.2. b (left) Schematic of the chromatin oligomerization assay. 12mer arrays were incubated in different buffer conditions, subjected to low-speed centrifugation, and the A260 of the supernatant was measured. The soluble fraction reflects the degree of self-association of the 12mer arrays. (right) Increasing concentrations of tau were incubated with 30 nM 12mer arrays (for an A260 ~ 1) in different salt conditions in the same buffer. Individual replicates are shown, and the line indicates the mean. c (left) Schematic of the MNase digestion assay to probe for DNA protection within 12mer arrays. (right) Time course of MNase digestion of 2 nM 12mer arrays with varying concentrations of tau and MgCl2, in the same buffer. All lanes contain a band at ~150 bp which results from a small amount of MMTV nucleosomes present in the sample.
