HDACs directly interact with all core histone subunits.

<p>(<b>A</b>) All histone subunits interact with HDAC1. Flag-tagged HDAC1 was incubated with the purified glutathione sepharose beads immobilized GST-H3, H4, H2A, or H2B in a pull-down assay and histone associated HDAC1 was detected by Western blotting. * indicates the protein of interest in Coomassie blue staining. (<b>B</b>) Histone subunits interact with other Class I HDACs. Flag-tagged HDAC 2 and 3 were incubated with the purified GST-histone H3, H4, H2A, or H2B and detected by Western blotting. * indicates the protein of interest in Coomassie blue staining. (<b>C</b>) Histone H3 interacts with Class II HDACs. The purified GST-histone H3 was incubated with Flag-tagged HDAC4, 5 and 6. Proteins bound to GST-H3 were separated in SDS-PAGE and detected by Western blotting. (<b>D</b>) Histone H3 tail 1-57 interacts with HDAC1 regardless of HDAC1 acetylation. Flag-tagged HDAC1 acetylation mimic mutant 6Q, single mutation of HDAC1 H141A and wild type HDAC1 were incubated with the purified GST-histone H3 1-57. Associated proteins were detected by Western blotting. Each experiment was repeated at least three times.