Figure 4.

Equivalent mutation of the CBX1 chromodomain like HP1α also increases binding to H3K9 methylation. a) and b) Images of histone peptide microarrays probed with either MBP-tagged wild-type (a) or engineered (b) CBX1 chromodomain. Color coded boxes indicate peptide types and positive controls (IgG). The red star indicates a peptide (H3K9me3 containing) hit that has been zoomed in on in the center, highlighting the change in binding between the two constructs. c) Scatter plot of the array data of wild-type versus engineered CBX1 chromodomains, scaled from 0–1, with the indicated types of peptides color coded; enhanced signal of the mutant is above the dashed line and decreased signal below it. d) Images of peptide pulldowns of the wild-type and mutant CBX1 domains with the indicated peptides. e) Scatter plot of the array data of engineered HP1α versus engineered CBX1 chromodomains, scaled from 0–1, with the indicated types of peptides color coded; enhanced signal of the mutant is above the dashed line and decreased signal below it. All arrays were performed using 500 nM of protein and all pulldowns with 5 pmol protein. All images and data are representative of n ≥ 3 experiments.