Project description:Background: Histone post-translational modifications (PTMs) constitute a branch of epigenetic mechanisms that can control the expression of eukaryotic genes in a heritable manner. Recent studies have identified several PTM-binding proteins containing diverse specialized domains whose recognition of specific PTM sites leads to gene activation or repression. Here, we present a high-throughput proteogenomic platform designed to characterize the nucleosomal make-up of chromatin enriched with a set of histone PTM-binding proteins known as histone PTM readers. We support our findings with gene expression data correlating to PTM distribution. Results: We isolated human mononucleosomes bound by the bromodomain-containing proteins Brd2, Brd3 and Brd4, and by the chromodomain-containing heterochromatin proteins HP1alpha and HP1beta. Histone PTMs were quantified by mass spectrometry (ChIP-qMS), and their associated DNAs were mapped using deep sequencing. Our results reveal that Brd- and HP1-bound nucleosomes are enriched in histone PTMs consistent with actively transcribed euchromatin and silent heterochromatin, respectively. Data collected using RNA-Seq (GSM301568) show that Brd-bound sites correlate with highly expressed genes. In particular, Brd3 and Brd4 are most enriched on nucleosomes located within HOX gene clusters, whose expression is reduced upon Brd4 depletion by shRNA. Conclusions: Proteogenomic mapping of histone PTM readers, alongside the characterization of their local chromatin environments and transcriptional information, should prove useful for determining how histone PTMs are bound by these readers and how they contribute to distinct transcriptional states. Examination of Brd and HP1 proteins-binding sites in HEK293 cells.
Project description:Memory T cells (TM) play a prominent role in protective and auto-immunity because they mount a more effective response than naïve T cells (TN), by rapidly expressing a large number of immune response genes upon stimulation. Previous studies have shown a correlation between increased histone acetylation levels and rapid gene expression at specific loci in CD8+ TM. However, the underlying mechanisms of histone acetylation remodeling in TM and its role in regulating global gene expression are not well defined, particularly in human TM cells. In this study, we examined the global level of histone acetylation and the expression of histone acetyltransferases and deacetylases , and found no differences between human CD8+ TN and TM cells. Through Genomegenome-wide mapping of the histone acetyltransferase p300 in human CD8+ TN and TM cells, recruitment of p300 was found to be positively correlated with the expression of 213 genes in TM and 516 genes in TN cells at rest, and was positively correlated with the expression of 556 genes in TM and 330 genes in TN cells after 4 hrs’ stimulation. Importantly, genes which have positive correlations between expression levels and p300 occupancy in TM were significantly enriched in effector functions of CD8+ T cells, while those in TN cells were over-presented in nucleic acid processing and cell differentiations. At IFNG locus, specifically, the recruitment of p300 was significantly higher in CD8+ TM than TN and cells that were correlated with increased levels of histone acetylation at this locus, and robust IFN-g expression by CD8+ TM cells. Selective inhibition of p300 and deletion of p300 binding sites within the IFNG promoter resulted in decreased histone acetylation at this locus and the lower expression level of IFN-g in CD8+ TM cells. These results suggest that recruitment of the histone acetyltransferase p300 modifies histone acetylation and allows rapid expression of IFNG, and likely a large set of immune response genes, in human CD8+ TM, which in turn contribute to the enhanced functionality of human CD8+ TM cells.
Project description:Background: Histone post-translational modifications (PTMs) constitute a branch of epigenetic mechanisms that can control the expression of eukaryotic genes in a heritable manner. Recent studies have identified several PTM-binding proteins containing diverse specialized domains whose recognition of specific PTM sites leads to gene activation or repression. Here, we present a high-throughput proteogenomic platform designed to characterize the nucleosomal make-up of chromatin enriched with a set of histone PTM-binding proteins known as histone PTM readers. We support our findings with gene expression data correlating to PTM distribution. Results: We isolated human mononucleosomes bound by the bromodomain-containing proteins Brd2, Brd3 and Brd4, and by the chromodomain-containing heterochromatin proteins HP1alpha and HP1beta. Histone PTMs were quantified by mass spectrometry (ChIP-qMS), and their associated DNAs were mapped using deep sequencing. Our results reveal that Brd- and HP1-bound nucleosomes are enriched in histone PTMs consistent with actively transcribed euchromatin and silent heterochromatin, respectively. Data collected using RNA-Seq (GSM301568) show that Brd-bound sites correlate with highly expressed genes. In particular, Brd3 and Brd4 are most enriched on nucleosomes located within HOX gene clusters, whose expression is reduced upon Brd4 depletion by shRNA. Conclusions: Proteogenomic mapping of histone PTM readers, alongside the characterization of their local chromatin environments and transcriptional information, should prove useful for determining how histone PTMs are bound by these readers and how they contribute to distinct transcriptional states. Comparison of Brd2 and HP1b shRNA knockdown HEK293 cells to control knockdown HEK293 cells.
Project description:Transcriptome analysis of ino4∆ and Mga2∆TM-overexpressing cells in order to understand the mechanism by which cells decide whether to synthesize LDs from the INM or not. A striking difference between the transcriptomes of Mga2∆TM-overexpressing cells (cLDs) and ino4∆ cells (cLDs and nLDs) is the fact that enzymes involved in PL synthesis, for example, the phosphatidylethanolamine methyltransferase CHO2 or the phospholipid methyltransferase OPI3, are downregulated specifically in ino4∆ cells. In contrast, Mga2∆TM overexpressing cells showed an upregulation of the Ole1 desaturase and Mvd1, an enzyme involved in sterol biosynthesis, whereas the expression of PL synthesis factors remained largely unchanged.
Project description:B-methylthiolation of the Escherichia coli Ribosomal Protein S12 Regulates Anaerobic Gene Expression. B-methylthiolation is a unique post-translational modification (PTM) that maps to a conserved Asp 88 of the bacterial ribosomal protein S12. This modification is phylogenetically conserved in several bacteria yet has not been identified on other proteins. We use microarrays to delineate the association of prokaryotic ribosomal protein PTM to the regulation of genes.
Project description:Background: Histone post-translational modifications (PTMs) constitute a branch of epigenetic mechanisms that can control the expression of eukaryotic genes in a heritable manner. Recent studies have identified several PTM-binding proteins containing diverse specialized domains whose recognition of specific PTM sites leads to gene activation or repression. Here, we present a high-throughput proteogenomic platform designed to characterize the nucleosomal make-up of chromatin enriched with a set of histone PTM-binding proteins known as histone PTM readers. We support our findings with gene expression data correlating to PTM distribution. Results: We isolated human mononucleosomes bound by the bromodomain-containing proteins Brd2, Brd3 and Brd4, and by the chromodomain-containing heterochromatin proteins HP1alpha and HP1beta. Histone PTMs were quantified by mass spectrometry (ChIP-qMS), and their associated DNAs were mapped using deep sequencing. Our results reveal that Brd- and HP1-bound nucleosomes are enriched in histone PTMs consistent with actively transcribed euchromatin and silent heterochromatin, respectively. Data collected using RNA-Seq (GSM301568) show that Brd-bound sites correlate with highly expressed genes. In particular, Brd3 and Brd4 are most enriched on nucleosomes located within HOX gene clusters, whose expression is reduced upon Brd4 depletion by shRNA. Conclusions: Proteogenomic mapping of histone PTM readers, alongside the characterization of their local chromatin environments and transcriptional information, should prove useful for determining how histone PTMs are bound by these readers and how they contribute to distinct transcriptional states.