Structural insights into trans-histone regulation of H3K4 methylation by unique histone H4 binding of MLL3/4

Abstract

MLL3 and MLL4 are members of the SET1/MLL family of histone H3K4 methyltransferases, which are responsible for monomethylating histone H3K4 on enhancers. Here the authors show that an extended PHD domain (ePHD6) in MLL3 and MLL4 specifically recognizes an H4H18-containing fragment of histone H4, and that modifications of residues surrounding H4H18 modulate H4 binding to MLL3/4.