Project description:Elucidation of interactions involving DNA and histone post-translational-modifications (PTMs) is essential for providing insight into complex biological functions. Reader assemblies connected via flexible linkages facilitate avidity and increase affinity, however little is known of the contribution to the recognition process of multiple PTMs due to rigidity in the absence of conformational flexibility. We report here the high resolution crystal structure of the triple-reader module (PHD-Bromo-PWWP) of ZMYND8 which forms a stable unit capable of simultaneously recognizing multiple histone PTMs, while presenting a charged platform for association with DNA. Single domain disruptions destroy the functional network of interactions initiated by ZMYND8, impairing recruitment to sites of DNA damage. Our data establish proof-of-principle that rigidity can be compensated by concomitant DNA and histone PTM interactions, maintaining multivalent engagement of transient chromatin states, thus identifying an important underappreciated role for rigid multivalent reader modules in nucleosome binding and chromatin function.
Project description:Elucidation of multivalent interactions involving both DNA and histone post-translational-modifications (PTMs) is essential for providing insight into complex biological functions. We report here the high resolution crystal structure of the N-terminal triple reader module (PHD-Bromo-PWWP) of ZMYND8, which forms a stable unit, capable of simultaneously recognizing histone PTMs and providing a charged platform for DNA interaction. Monte Carlo simulations provide a model whereby the reader module directly engages the core nucleosome particle, extracting the entire histone H3 tail and initiating contacts with the DNA super-coil structure. Systematic mutation of these interaction interfaces reveals cooperativity within the ensemble. Single domain disruption destroys the functional network of interactions initiated by ZMYND8, which impairs recruitment to sites of DNA damage and alters transcription. Taken together, our results establish an important role of the ZMYND8 multivalent reader module in nucleosome binding and chromatin function.
Project description:Histone 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. 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.
Project description:Cancer cell type-selective addiction of transcription-chromatin regulatory program provides opportunities for therapeutic interventions. Here, we uncovered an IRF8-MEF2D transcription factor (TF) regulatory circuit as an acute myeloid leukemia (AML)-biased dependency. Combining CRISPR-based genetic screens, transcriptional analysis, and chromatin profiling, we demonstrated that a chromatin regulator, ZMYND8, directly regulates IRF8 and MYC expression through occupying AML-specific enhancer regions. ZMYND8 was essential for AML proliferation both in vitro and in vivo. The ZMYND8-occupied IRF8 enhancer was further characterized using Circular Chromosome Conformation Capture and CRISPRi-based perturbation assays and was observed in primary patient cells. Importantly, mutagenesis experiments revealed that the PHD/Bromodomain/PWWP reader module is required for ZMYND8 tethering to leukemia-essential co-activator BRD4 for enhancer-mediated gene regulation. Our results rationalize ZMYND8 as a potential selective therapeutic target for modulating the IRF8/MYC transcriptional networks in AML.
Project description:Cancer cell type-selective addiction of transcription-chromatin regulatory program provides opportunities for therapeutic interventions. Here, we uncovered an IRF8-MEF2D transcription factor (TF) regulatory circuit as an acute myeloid leukemia (AML)-biased dependency. Combining CRISPR-based genetic screens, transcriptional analysis, and chromatin profiling, we demonstrated that a chromatin regulator, ZMYND8, directly regulates IRF8 and MYC expression through occupying AML-specific enhancer regions. ZMYND8 was essential for AML proliferation both in vitro and in vivo. The ZMYND8-occupied IRF8 enhancer was further characterized using Circular Chromosome Conformation Capture and CRISPRi-based perturbation assays and was observed in primary patient cells. Importantly, mutagenesis experiments revealed that the PHD/Bromodomain/PWWP reader module is required for ZMYND8 tethering to leukemia-essential co-activator BRD4 for enhancer-mediated gene regulation. Our results rationalize ZMYND8 as a potential selective therapeutic target for modulating the IRF8/MYC transcriptional networks in AML.
Project description:Cancer cell type-selective addiction of transcription-chromatin regulatory program provides opportunities for therapeutic interventions. Here, we uncovered an IRF8-MEF2D transcription factor (TF) regulatory circuit as an acute myeloid leukemia (AML)-biased dependency. Combining CRISPR-based genetic screens, transcriptional analysis, and chromatin profiling, we demonstrated that a chromatin regulator, ZMYND8, directly regulates IRF8 and MYC expression through occupying AML-specific enhancer regions. ZMYND8 was essential for AML proliferation both in vitro and in vivo. The ZMYND8-occupied IRF8 enhancer was further characterized using Circular Chromosome Conformation Capture and CRISPRi-based perturbation assays and was observed in primary patient cells. Importantly, mutagenesis experiments revealed that the PHD/Bromodomain/PWWP reader module is required for ZMYND8 tethering to leukemia-essential co-activator BRD4 for enhancer-mediated gene regulation. Our results rationalize ZMYND8 as a potential selective therapeutic target for modulating the IRF8/MYC transcriptional networks in AML.
Project description:Cancer cell type-selective addiction of transcription-chromatin regulatory program provides opportunities for therapeutic interventions. Here, we uncovered an IRF8-MEF2D transcription factor (TF) regulatory circuit as an acute myeloid leukemia (AML)-biased dependency. Combining CRISPR-based genetic screens, transcriptional analysis, and chromatin profiling, we demonstrated that a chromatin regulator, ZMYND8, directly regulates IRF8 and MYC expression through occupying AML-specific enhancer regions. ZMYND8 was essential for AML proliferation both in vitro and in vivo. The ZMYND8-occupied IRF8 enhancer was further characterized using Circular Chromosome Conformation Capture and CRISPRi-based perturbation assays and was observed in primary patient cells. Importantly, mutagenesis experiments revealed that the PHD/Bromodomain/PWWP reader module is required for ZMYND8 tethering to leukemia-essential co-activator BRD4 for enhancer-mediated gene regulation. Our results rationalize ZMYND8 as a potential selective therapeutic target for modulating the IRF8/MYC transcriptional networks in AML.
Project description:Cancer cell type-selective addiction of transcription-chromatin regulatory program provides opportunities for therapeutic interventions. Here, we uncovered an IRF8-MEF2D transcription factor (TF) regulatory circuit as an acute myeloid leukemia (AML)-biased dependency. Combining CRISPR-based genetic screens, transcriptional analysis, and chromatin profiling, we demonstrated that a chromatin regulator, ZMYND8, directly regulates IRF8 and MYC expression through occupying AML-specific enhancer regions. ZMYND8 was essential for AML proliferation both in vitro and in vivo. The ZMYND8-occupied IRF8 enhancer was further characterized using Circular Chromosome Conformation Capture and CRISPRi-based perturbation assays and was observed in primary patient cells. Importantly, mutagenesis experiments revealed that the PHD/Bromodomain/PWWP reader module is required for ZMYND8 tethering to leukemia-essential co-activator BRD4 for enhancer-mediated gene regulation. Our results rationalize ZMYND8 as a potential selective therapeutic target for modulating the IRF8/MYC transcriptional networks in AML.
Project description:Cancer cell type-selective addiction of transcription-chromatin regulatory program provides opportunities for therapeutic interventions. Here, we uncovered an IRF8-MEF2D transcription factor (TF) regulatory circuit as an acute myeloid leukemia (AML)-biased dependency. Combining CRISPR-based genetic screens, transcriptional analysis, and chromatin profiling, we demonstrated that a chromatin regulator, ZMYND8, directly regulates IRF8 and MYC expression through occupying AML-specific enhancer regions. ZMYND8 was essential for AML proliferation both in vitro and in vivo. The ZMYND8-occupied IRF8 enhancer was further characterized using Circular Chromosome Conformation Capture and CRISPRi-based perturbation assays and was observed in primary patient cells. Importantly, mutagenesis experiments revealed that the PHD/Bromodomain/PWWP reader module is required for ZMYND8 tethering to leukemia-essential co-activator BRD4 for enhancer-mediated gene regulation. Our results rationalize ZMYND8 as a potential selective therapeutic target for modulating the IRF8/MYC transcriptional networks in AML.
Project description:Cancer cell type-selective addiction of transcription-chromatin regulatory program provides opportunities for therapeutic interventions. Here, we uncovered an IRF8-MEF2D transcription factor (TF) regulatory circuit as an acute myeloid leukemia (AML)-biased dependency. Combining CRISPR-based genetic screens, transcriptional analysis, and chromatin profiling, we demonstrated that a chromatin regulator, ZMYND8, directly regulates IRF8 and MYC expression through occupying AML-specific enhancer regions. ZMYND8 was essential for AML proliferation both in vitro and in vivo. The ZMYND8-occupied IRF8 enhancer was further characterized using Circular Chromosome Conformation Capture and CRISPRi-based perturbation assays and was observed in primary patient cells. Importantly, mutagenesis experiments revealed that the PHD/Bromodomain/PWWP reader module is required for ZMYND8 tethering to leukemia-essential co-activator BRD4 for enhancer-mediated gene regulation. Our results rationalize ZMYND8 as a potential selective therapeutic target for modulating the IRF8/MYC transcriptional networks in AML.