show Abstracthide AbstractHistone acetylation, including acetylated H3K14 (H3K14ac), is generally linked to gene activation. Monomethylated histone H3 lysine 4 (H3K4me1), together with other gene-activating marks, denotes active genes. In contrast to usual gene-activating functions of H3K14ac and H3K4me1, we here show that the dual histone modification mark H3K4me1-H3K14ac is recognized by ZMYND8 (also called RACK7) and functions to counteract gene expression. We identified ZMYND8 as a transcriptional corepressor of the H3K4 demethylase JARID1D. ZMYND8 antagonizes the expression of metastasis-linked genes, and its knockdown increases the cellular invasiveness in vitro and in vivo. The plant homeodomain (PHD) and Bromodomain cassette in ZMYND8 mediates the combinatorial recognition of H3K4me1-H3K14ac and H3K4me0-H3K14ac by ZMYND8. These findings uncover an unexpected role for the signature H3K4me1-H3K14ac in attenuating gene expression and reveal a previously unknown metastasis-suppressive epigenetic mechanism in which ZMYND8's PHD-Bromo cassette couples H3K4me1-H3K14ac with repression of metastasis-linked genes. Overall design: i) ChIP-Seq data of ZMYND8, JARID1D, H3K4me1, H3K14ac, H3K4me3, and H3K27me3 in normal DU145 cells. ii) ChIP-Seq data of H3K4me1 and H3K4me3 in shLuciferase-, shJARID1D-, or shZMYND8-treated DU145 cells. iii) RNA-Seq data in shLuciferase-, shJARID1D-, or shZMYND8-treated DU145 cells.