Project description:Histone lysine acetylation and methylation regulate gene transcription through coordination of chromatin structure and transcriptional activity. However, our understanding of the role of histones in gene regulation is far from complete, in part due to newly discovered novel histone modifications, whose functions are yet to be uncovered1. Here we report that histone H3 lysine 27 crotonylation (H3K27cr) is selectively recognized by the YEATS domain of GAS41 in association with SIN3a-HDAC1/2 co-repressor complex for gene transcriptional repression. The GAS41 YEATS domain dimer binds proto-oncogenic transcription factor c-Myc, which recruits GAS41/SIN3a-HDAC1/2 complex to target gene loci in chromatin such as cell cycle inhibitor p21. Transcriptional de-repression of p21, directed by tumor suppressor p53 upon doxorubicin stimulation, entails dissociation of c-Myc/GAS41/SIN3a-HDAC1/2 complex from chromatin, reduced H3K27 crotonylation, and consequentially increased H3K27 acetylation at p21 locus. GAS41 knockout or H3K27cr binding depletion with CRISPR/Cas9 results in p21 activation, cell cycle arrest and tumor growth inhibition in mice. Our study explains mechanistically causal effect of GAS41 and c-Myc gene amplification on down-regulation of p21 in human colorectal cancer, and suggests GAS41 as an anti-cancer target. We propose that H3K27 crotonylation represents a previously unrecognized, distinct chromatin state for gene transcriptional repression in contrast to H3K27 trimethylation for long-term transcriptional silencing and H3K27 acetylation for transcriptional activation.
Project description:Histone lysine acylation, including acetylation and crotonylation, plays a pivotal role in gene transcription in health and diseases. However, our understanding of histone lysine acylation has been limited to gene transcriptional activation. Here, we report that histone H3 lysine 27 crotonylation (H3K27cr) directs gene transcriptional repression rather than activation. Specifically, H3K27cr in chromatin is selectively recognized by the YEATS domain of GAS41 in complex with SIN3A-HDAC1 co-repressors. Proto-oncogenic transcription factor MYC recruits GAS41/SIN3A-HDAC1 complex to repress genes in chromatin, including cell-cycle inhibitor p21. GAS41 knockout or H3K27cr-binding depletion results in p21 de-repression, cell-cycle arrest, and tumor growth inhibition in mice, explaining a causal relationship between GAS41 and MYC gene amplification and p21 downregulation in colorectal cancer. Our study suggests that H3K27 crotonylation signifies a previously unrecognized, distinct chromatin state for gene transcriptional repression in contrast to H3K27 trimethylation for transcriptional silencing and H3K27 acetylation for transcriptional activation.
Project description:Normal cell type specific histone H3 lysine 27 trimethylation of miRNA genes. HMEC and HMF represent two distinct differentiated cell type present in mammary gland each with a distinct phenotype, a distinct epigenotype as well as distinct miRNA expression pattern. The aim of the study was to determine how epigenetic modifications including histone H3 lysine 27 trimethylation affect miRNA expression. Two cell types HMEC vs. HMF. Biological replicates: 3 pairs of HMEC-HMF of 3 distinct genotypes. Immunoprecipitation using anti-histone H3 trimethylated at lysine 27 (07-449, Millipore).
Project description:Normal cell type specific histone H3 lysine 27 trimethylation of miRNA genes. HMEC and HMF represent two distinct differentiated cell type present in mammary gland each with a distinct phenotype, a distinct epigenotype as well as distinct miRNA expression pattern. The aim of the study was to determine how epigenetic modifications including histone H3 lysine 27 trimethylation affect miRNA expression.
Project description:Utilizing a single nuclei multiomics approach, this study elucidates how enhancing histone lysine crotonylation regulates cell type specific gene expression and chromatin accessibility during memory consolidation.
Project description:Polycomb Repressor Complex 2 (PRC2) is a multi-protein epigenetic regulator complex that plays critical roles in early development and tissue differentiation. The complex catalyzes the methylation of histone H3 lysine 27 (H3K27). The tri-methyl state (H3K27me3) is well studied as an agent of gene repression, but more recently distinct roles for the mono- and di-methyl states have been discovered. In order to more fully understand how PRC2-associated factors might influence H3K27 status, we screened for physical associations of PRC2 subunits. Knockdown of these factors was used to produce functional interaction maps focused on H3K27 methylation, including proteins that have positive and negative effects on the levels each histone mark.
Project description:Lysine crotonylation on histones is a recently identified post-translational modification that has been demonstrated to associate with active promoters and to directly stimulate transcription.Given that crotonyl-CoA is essential for the acyl transfer reaction and it is a metabolic intermediate widely localized within the cell, we postulate that lysine crotonylation on non-histone proteins could also widely exist. Using specific antibody to enrich crotonylated lysine(Kcr) peptides followed by high-resolution mass spectrometry analysis reveals that crotonylated proteins and lysine residues. Bioinformatic analysis reveals that crotonylated proteins are particularly enriched in the nuclei, that lysine crotonylation alters level of the modified proteins in the chromatin and that cotonylation of a subset of proteins influences DNA replication and cell cycle. Taken together, our data indicate that lysine crotonylation could be induced in a large number of proteins other than histones and this type of acyl modification could play an important role regulating multiple cellular processes.
Project description:We isolated E12.5 TrkC neurons and profiled Runx3, Brn3a binding and Histone H3 acetylated on lysine 27 (H3K27Ac) during early development of DRG TrkC neurons by Cut&Run
Project description:We report the identification of 67 previously undescribed histone modifications, increasing the current number of known histone marks by about 70%. We further investigated one of the marks, lysine crotonylation (Kcr), confirming that it represents an evolutionarily-conserved histone posttranslational modification. The unique structure and genomic localization of histone Kcr suggest that it is mechanistically and functionally different from histone lysine acetylation (Kac). Specifically, in both human somatic and mouse male germ cell genomes, histone Kcr marks either active promoters or potential enhancers. In male germinal cells immediately following meiosis, Kcr is enriched on sex chromosomes and specifically marks testis-specific genes, including a significant proportion of X-linked genes that escape sex chromosome inactivation in haploid cells. These results therefore dramatically extend the repertoire of histone PTM sites and designate Kcr as a specific mark of active sex chromosome-linked genes in postmeiotic male germ cells. 2 histone marks (pan-lysine acetylation and pan-lysine crotonylation) were studied in 1 human cell type and 2 mouse cell types using ChIP-Seq. Input was sequenced for each cell type as a control. Pan-anti_Kac and pan-anti_Kcr antibodies were custom developed with PTM BioLab, Co., Ltd (Chicago, IL).