ZMYND8 (zinc finger MYND (Myeloid, Nervy and DEAF-1)-type containing 8), a newly identified component of the transcriptional coregulator network, was found to interact with the Nucleosome Remodeling and Deacetylase (NuRD) complex. Previous reports have shown that ZMYND8 is instrumental in recruiting the NuRD complex to damaged chromatin for repressing transcription and promoting double strand break repair by homologous recombination. However, the mode of transcription regulation by ZMYND8 has remained elusive. Here, we report that through its specific key residues present in its conserved chromatin-binding modules, ZMYND8 interacts with the selective epigenetic marks H3.1K36Me2/H4K16Ac. Furthermore, ZMYND8 shows a clear preference for canonical histone H3.1 over variant H3.3. Interestingly, ZMYND8 was found to be recruited to several developmental genes, including the all-trans-retinoic acid (ATRA)-responsive ones, through its modified histone-binding ability. Being itself inducible by ATRA, this zinc finger transcription factor is involved in modulating other ATRA-inducible genes. We found that ZMYND8 interacts with transcription initiation-competent RNA polymerase II phosphorylated at Ser-5 in a DNA templatedependent manner and can alter the global gene transcription. Overall, our study identifies that ZMYND8 has CHD4-independent functions in regulating gene expression through its modified histone-binding ability.ZMYND8 (zinc finger MYND (Myeloid, Nervy and DEAF-1)-type containing 8) is a putative chromatin reader/effector harboring a PWWP domain, a bromodomain, and a PHD type zinc finger. It associates with the CHD4 protein of NuRD chromatin remodeling complex implicated in gene transcription, cell cycle progression, and genome integrity (1, 2). Reader proteins specifically recognize histone post-translational modifications (PTMs) 5 and translate such recognition(s) into meaningful biological outcomes by virtue of either their intrinsic activities or those of their interacting partners (3). These readers may interpret histone PTMs via "monovalent" or "multivalent" recognition (4). In monovalent recognition, a chromatin reader recognizes one histone PTM. In contrast, in multivalent recognition, readers recognize multiple histone modifications intra/inter-nucleosomally. An accessible surface is provided by these readers (such as a cavity or surface groove), which accommodates the modified histone residues, and determines the modification (e.g. acetylation versus methylation) or state specificity (such as mono-versus trimethylation of lysine) (3).ZMYND8 is a well known component of the transcription coregulator complex and is associated with several demethylase machinery components, including KDM5A, KDM5C, or LSD1 (5, 6). Through its ability to interact with Xenopus RCoR2, ZMYND8 plays a significant role in embryonic neural differentiation (7). Apart from this, ZMYND8 is also involved in T-cell lymphoma and breast and cervical cancer (8 -10). Another interesting feature is that ZMYND8 is significantly involved...

The roles of Plant Homeodomain (PHD) fingers in catalysis of histone modifications are unknown. We demonstrated that the PHD finger of Ubiquitin Protein Ligase E3 Component N-Recognin7 (UBR7) harbors E3 ubiquitin ligase activity toward monoubiquitination of histone H2B at lysine120 (H2BK120Ub). Purified PHD finger or full-length UBR7 monoubiquitinated H2BK120 in vitro, and loss of UBR7 drastically reduced H2BK120Ub genome-wide binding sites in MCF10A cells. Low UBR7 expression was correlated with occurrence of triple-negative breast cancer and metastatic tumors. Consistently, UBR7 knockdown enhanced the invasiveness, induced epithelial-to-mesenchymal transition and promoted metastasis. Conversely, ectopic expression of UBR7 restored these cellular phenotypes and reduced tumor growth. Mechanistically, UBR7 loss reduced H2BK120Ub levels on cell adhesion genes, including CDH4, and upregulated the Wnt/β-Catenin signaling pathway. CDH4 overexpression could partially revert UBR7-dependent cellular phenotypes. Collectively, our results established UBR7 as a histone H2B monoubiquitin ligase that suppresses tumorigenesis and metastasis of triple-negative breast cancer.