Figure 4.
Acetylation status of H3K18 regulates MMP-9 activity. (A) The indicated H3 peptides (amino acids 10–35) were incubated with increasing concentrations of rMMP-9 (X-axis), and proteolysis was measured fluorometrically by reaction of free amino groups with fluorescamine (Y-axis). The Vmax and Km values were obtained by nonlinear regression fit. (B) H3NT cleavage assays using rMMP-9 and the indicated rH3 acetyl-lysine analog substrates either alone (top) or as reconstituted nucleosome arrays (bottom). (C) H3NT cleavage assays using rMMP-9 and recombinant (top) or native (bottom) nucleosome array substrates. (D) Western blot analysis of nuclear lysates from 3-d OCP-induced cells expressing a control or CBP/p300-specific shRNA using the indicated antibodies. (E) OCP cells transduced with a control or CBP/p300-specific shRNA (top) or treated with DMSO control or a selective CBP/p300 inhibitor (bottom). H3NT cleavage was assessed at the indicated days after induction. See also Supplemental Figure 4.