Recognition of a mononucleosomal histone modification pattern by BPTF via multivalent interactions.
Little is known about how combinations of histone marks are interpreted at the level of nucleosomes. The second PHD finger of human BPTF is known to specifically recognize histone H3 when methylated on lysine 4 (H3K4me2/3). Here, we examine how additional heterotypic modifications influence BPTF binding. Using peptide surrogates, three acetyllysine ligands are indentified for a PHD-adjacent bromodomain in BPTF via systematic screening and biophysical characterization. Although the bromodomain displays limited discrimination among the three possible acetyllysines at the peptide level, marked selectivity is observed for only one of these sites, H4K16ac, in combination with H3K4me3 at the mononucleosome level. In support, these two histone marks constitute a unique trans-histone modification pattern that unambiguously resides within a single nucleosomal unit in human cells, and this module colocalizes with these marks in the genome. Together, our data call attention to nucleosomal patterning of covalent marks in dictating critical chromatin associations.
PubMed ID: 21596426
PMC ID: PMC3135172
Article link: Cell.
Grant support: R01 GM040922-26 NIGMS NIH HHS , R01 GM040922-27 NIGMS NIH HHS , R37 GM053512-29 NIGMS NIH HHS , R37 GM053512-30 NIGMS NIH HHS , P30 EB009998 NIBIB NIH HHS , R01 GM040922 NIGMS NIH HHS , R37 GM053512 NIGMS NIH HHS
Genes referenced: bptf