Project description:The histone variant H2A.Z is essential for maintaining the identity of embryonic stem cell (ESC) by keeping bivalent developmental genes at a poised state. However, how H2A.Z is deposited into the bivalent domains remains unknown. In mammals, two chromatin-remodeling complexes, Tip60/p400 and SRCAP, exchange the canonical histone H2A for H2A.Z in the chromatin. Here we show that Glioma Amplified Sequence 41 (Gas41), a shared subunit of the two H2A.Z-depositing complexes, functions as a reader of histone acetylation and recruits Tip60/p400 and SRCAP to deposit H2A.Z into specific chromatin regions including bivalent domains. The YEATS domain of Gas41 bound to acetylation on histone H3K27 and H3K14 both in vitro and in cells. Crystal structure of the Gas41 YEATS domain in complex with the H3K27ac peptide revealed that, similar to the AF9 and ENL YEATS domains, Gas41 YEATS forms a serine-lined aromatic cage for Kac recognition; mutations of either the aromatic residues of YEATS domain or the nearby residue of H3K27 abrogated the interaction. In mESCs, knockdown of Gas41 led to cell differentiation as the result of derepression of differentiation genes. Importantly, the differentiated morphology was rescued by expressing wild type Gas41, but not the YEATS domain mutated counterparts that do not recognize histone acetylation. Mechanically, we found that Gas41 depletion led to reduction of H2A.Z levels and a concomitant reduction of H3K27me3 levels at the promoters of a subset of bivalent genes. Together, our study identifies the Gas41 YEATS domain as a reader of histone acetylation and establishes a link between histone acetylation and H2A.Z deposition in the maintenance of ESC identity.
Project description:Histone acetylation is associated with active transcription in eukaryotic cells. It helps to open up the chromatin by neutralizing the positive charge of histone lysine residues, and by providing binding platforms for “reader” proteins. The bromodomain (BRD) has long been thought to be the sole protein module that recognizes acetylated histones. Recently, we identified the YEATS domain of AF9 as a novel acetyllysine-binding module, and showed that the ENL YEATS domain is an essential acetyl-histone reader in acute myeloid leukemias. The human genome encodes four YEATS domain proteins, including GAS41; however, the importance of the GAS41 YEATS domain, in human cancer remains largely unknown. Here we report that GAS41 is frequently amplified in human non-small cell lung cancer (NSCLC) and is required for cancer cell proliferation, survival, and transformation. Biochemical and crystal structural studies demonstrate that GAS41 binds to histone H3 acetylated on H3K27 and H3K14, a specificity that is distinct from that of AF9 or ENL. ChIP-seq analyses in lung cancer cells reveal that GAS41 colocalizes with H3K27ac and H3K14ac on the promoters of actively transcribed genes. Depletion of GAS41 or disruption of the interaction between its YEATS domain and acetylated histones impairs the association of histone variant H2A.Z with chromatin, and consequently, suppresses cancer cell growth and survival both in vitro and in vivo. Overall, our study identifies GAS41 as a histone acetylation reader that controls a transcriptional program essential for NSCLC tumorigenesis by modulating histone H2A.Z deposition.
Project description:The recognition of modified histones by “reader” proteins constitutes a key mechanism regulating gene expression in the chromatin context. Compared with the great variety of readers for histone methylation, few protein modules that recognize histone acetylation are known. Here we show that the evolutionarily conserved YEATS domains constitute a novel family of acetyllysine readers. The human AF9 YEATS domain binds strongly to histone H3K9 acetylation and, to a lesser extent, H3K27 and H3K18 acetylation. Crystal structural studies revealed that AF9 YEATS adopts an eight-stranded immunoglobin fold and utilizes a serine-lined aromatic “sandwiching” cage for acetyllysine readout, representing a novel recognition mechanism that is distinct from that of known acetyllysine readers. Histone acetylation recognition by AF9 is important for the chromatin recruitment of the H3K79 methyltransferase DOT1L. Together, our studies identify the YEATS domain as a novel acetyllysine-binding module, thereby establishing the first direct link between histone acetylation and DOTL1-mediated H3K79 methylation in transcription control. ChIP-seq analysis of AF9, H3K79me3, H3K9ac in Hela cells and H3K79me3 in Hela AF9 knockdown and Hela Dot1L knockdown cells.
Project description:The recognition of modified histones by “reader” proteins constitutes a key mechanism regulating gene expression in the chromatin context. Compared with the great variety of readers for histone methylation, few protein modules that recognize histone acetylation are known. Here we show that the evolutionarily conserved YEATS domains constitute a novel family of acetyllysine readers. The human AF9 YEATS domain binds strongly to histone H3K9 acetylation and, to a lesser extent, H3K27 and H3K18 acetylation. Crystal structural studies revealed that AF9 YEATS adopts an eight-stranded immunoglobin fold and utilizes a serine-lined aromatic “sandwiching” cage for acetyllysine readout, representing a novel recognition mechanism that is distinct from that of known acetyllysine readers. Histone acetylation recognition by AF9 is important for the chromatin recruitment of the H3K79 methyltransferase DOT1L. Together, our studies identify the YEATS domain as a novel acetyllysine-binding module, thereby establishing the first direct link between histone acetylation and DOTL1-mediated H3K79 methylation in transcription control.
Project description:Recognition of modified histones by “reader” proteins constitutes a key mechanism regulating diverse chromatin-associated processes important for normal and neoplastic development. For instance, bromodomain-containing proteins bind to acetylated histones and regulate chromatin dynamics and gene expression. We recently identified the YEATS domain as a novel acetyllysine-binding module; however, the functional importance of YEATS domain-containing proteins in human cancer remains largely unknown. Here we show that the YEATS2 gene is highly amplified in human non-small cell lung cancer (NSCLC) and is required for cancer cell growth and survival. Biochemical and crystal structural studies show that YEATS2 binds to acetylated histone H3, and the YEATS domain utilizes a serine-lined aromatic “sandwiching” cage for acetyllysine readout. ChIP-seq analyses in lung cancer cells reveal that the YEATS2-containing ATAC complex colocalizes with H3K27 acetylation (H3K27ac) on the promoters of actively transcribed genes. Depletion of YEATS2 or disruption of the interaction between its YEATS domain and acetylated histones reduces the ATAC complex-dependent promoter H3K9ac levels and deactivates the expression of essential genes, including the ribosomal protein-encoding genes, which are important for cancer cell growth and survival. Taken together, our study identifies YEATS2 as a histone H3K27ac specific reader that regulates a transcriptional program essential for NSCLC tumorigenesis.
Project description:Both, acetylation of histones and of histone variant H2A.Z are conserved features of eukaryotic transcription start sites (TSSs) and both features appear to be critical for correct transcription initiation. However, complex patterns of transcriptional regulation have complicated the establishment of functional links between histone acetylation, H2A.Z deposition and their importance in transcription regulation. To elucidate these links, we took advantage of the unusual genome organization in Trypanosoma brucei, a highly divergent eukaryote. In T. brucei genes are organized in long polycistronic transcription units, drastically reducing the sites of transcription initiation. Employing a highly sensitive and quantitative mass-spectrometry-based approach, we quantified the genome-wide histone acetylation and methylation pattern and identified various acetyl and methyl marks exclusively enriched at TSSs In addition, we show that deletion of histone acetyltransferase 2 results in a loss of H4 acetylation at TSSs, a loss of H2A.Z deposition at TSSs and a shift in the sites of transcription initiation. Combined, our findings demonstrate an evolutionary conserved link between histone H4 acetylation, H2A.Z deposition and RNA transcription initiation.
Project description:Recognition of post-translational modifications on histones by epigenetic readers is a fundamental mechanism for the regulation of chromatin and transcription. Compared to the large number of readers that recognize histone methylation, only a few acetyllysine readers have been identified, including bromodomain, YEATS, and double plant homeodomain zinc finger (DPF). Here, we report the identification of a novel reader of histone H3, the ZZ-type zinc finger (ZZ) domain of ZZZ3, a subunit of the Ada-Two-A Containing (ATAC) histone acetyltransferase complex. The solution NMR structure of the ZZ in complex with the H3 peptide reveals a unique histone-binding mechanism involving caging of the N-terminal Alanine 1 of histone H3 in an acidic cavity of the ZZ domain. Importantly, acetylation on Lysine 4 of H3 (H3K4ac) enhances the binding, and in cells, ZZZ3 colocalizes with H3K4ac across the genome. The recognition of histone acetylation by ZZ is essential for chromatin occupancy of ZZZ3 and functions of the ATAC complex. Depletion of ZZZ3 or disruption of the ZZ-H3 interaction dampens ATAC dependent promoter histone H3K9 acetylation and the expression of ribosomal protein encoding genes. Overall, our study identifies the ZZ domain of ZZZ3 as a novel epigenetic reader that links the GCN5/ATAC complex to histone acetylation.
Project description:Crucial mechanisms are required to restrict self-propagating heterochromatin spreading within defined boundaries and prevent euchromatic gene silencing. In the filamentous fungus Neurospora crassa, the JmjC domain protein DNA METHYLATION MODULATOR-1 (DMM-1) prevents aberrant spreading of heterochromatin, but the molecular details remain unknown. Here, we revealed that DMM-1 is highly enriched in a well-defined 5-kb heterochromatin domain and constrained its aberrant spreading. Interestingly, aberrant spreading of the 5-kb heterochromatin domain observed in the dmm-1KO strain is accompanied by the sharp deposition of histone variant H2A.Z, and deletion of H2A.Z abolishes aberrant spreading of the 5-kb heterochromatin domain into adjacent euchromatin. Furthermore, lysine 56 of histone H3 is deacetylated at the expanded heterochromatin regions, and mimicking H3K56 acetylation with an H3K56Q mutation effectively blocks H2A.Z-mediated aberrant spreading of the 5-kb heterochromatin domain. More importantly, genome-wide analyses demonstrated the general roles of H3K56 deacetylation and H2A.Z deposition in aberrant spreading of heterochromatin. Altogether, our results illustrate a previously unappreciated regulatory process that mediates aberrant heterochromatin spreading.
Project description:The goal was to investigate genome-wide if JAZF1 influences the deposition as well as the acetylation of the histone variant H2A.Z. ChIP-seq analysis revealed that depletion of JAZF1 leads to reduced acetylation of H2A.Z at specific sites.
Project description:Cancer cells are characterized by aberrant epigenetic landscapes and often exploit the chromatin machinery to activate oncogenic gene expression programs1. The recognition of modified histones by “reader” proteins constitutes a key mechanism underlying these processes; therefore targeting such pathways holds clinical promise, as exemplified by the recent development of BET bromodomain inhibitors2,3. We recently identified the YEATS domain as a novel acetyllysine-binding module4, yet its functional importance in human cancer remains unknown. Here we show that the YEATS domain-containing protein ENL, but not its paralog AF9, is required for disease maintenance in a variety of acute myeloid leukaemias (AML). CRISPR-Cas9 mediated depletion of ENL led to anti-leukemic effects, including increased terminal myeloid differentiation and suppression of leukaemia growth in vitro and in vivo. Biochemical and crystal structural studies in vitro and ChIP-seq analyses in leukaemia cells revealed that ENL binds to acetylated histone H3, and colocalizes with H3K27ac and H3K9ac on the promoters of actively transcribed genes that are essential for leukaemias. Disrupting the interaction between the YEATS domain and histone acetylation via structure-based mutagenesis reduced RNA polymerase II recruitment on ENL target genes, thus leading to suppression of oncogenic gene expression programs. Importantly, disruption of ENL’s functionality further sensitized leukaemia cells to BET inhibitors. Together, our study identifies ENL as a histone acetylation reader that regulates oncogenic transcriptional programs in AML and suggests that displacement of ENL from chromatin is a promising epigenetic therapy alone or in combination with BET inhibitors for AML