Project description:The locations of transcriptional enhancers and promoters were recently mapped in many mammalian cell types. Proteins that bind those regulatory regions can determine cell identity but have not been systematically identified. Here we purify native enhancers, promoters or heterochromatin from embryonic stem cells by chromatin immunoprecipitations (ChIP) for characteristic histone modifications and identify associated proteins using mass spectrometry (MS). 239 factors are identified and predicted to bind enhancers or promoters with different levels of activity, or heterochromatin. Published genome-wide data indicate a high accuracy of location prediction by ChIP-MS. A quarter of the identified factors are important for pluripotency and includes Oct4, Esrrb, Klf5, Mycn and Dppa2, factors that drive reprogramming to pluripotent stem cells. We determined the genome-wide binding sites of Dppa2 and find that Dppa2 operates outside the classical pluripotency network. Our ChIP-MS method provides a detailed read-out of the transcriptional landscape representative of the investigated cell type.
Project description:Our understanding of the functions of DNA elements is limited by the paucity of information about the spectrum of proteins that occupy these genomic regions. Here we describe an approach to identify proteins associated with genomic regions whose chromatin is marked by specific modified histones, which we term chromatin profiling. We used chromatin immunoprecipitation followed by mass spectrometry (ChIP-MS) to identify proteins associated with genomic regions marked by histone H3K27Ac, H3K4me3, H3K79me2 and H3K36me3 in mouse embryonic stem (mES) cells. We identified 385 known and 224 novel candidate proteins associated with these histone-marked genomic segments and confirmed that several of the novel candidates are indeed associated with histone-marked segments of the genome. Future study of the novel candidates, many of which have been implicated in various diseases, should lead to an improved understanding of gene control and its dysregulation in disease. ChIP-seq for nucleosomes with modified histones and DNA-binding proteins in mouse embryonic stem cells, and DNA-binding proteins in Jurkat cells
Project description:We characterize histone crotonylation in intestinal epithelium-derived cells through Mass spectrometry, ChIp-Seq and RNA-Seq approaches and show that this modification is removed by class I histone deacetylases, HDAC1, 2 and 3.
Project description:Our understanding of the functions of DNA elements is limited by the paucity of information about the spectrum of proteins that occupy these genomic regions. Here we describe an approach to identify proteins associated with genomic regions whose chromatin is marked by specific modified histones, which we term chromatin profiling. We used chromatin immunoprecipitation followed by mass spectrometry (ChIP-MS) to identify proteins associated with genomic regions marked by histone H3K27Ac, H3K4me3, H3K79me2 and H3K36me3 in mouse embryonic stem (mES) cells. We identified 385 known and 224 novel candidate proteins associated with these histone-marked genomic segments and confirmed that several of the novel candidates are indeed associated with histone-marked segments of the genome. Future study of the novel candidates, many of which have been implicated in various diseases, should lead to an improved understanding of gene control and its dysregulation in disease.
Project description:We report the usage of ChIP-mass spectrometry in identifying proteins and histone modifications involved in Drosophila dosage compensation. We identified a chromatin targeting factor, CG4747, that is involved in recognition of H3K36me3 and robust recruitment of the Drosophila MSL complex to its correct targets on the male X chromosome. ChIP-seq with PAP antibody of Drosophila larvae expressing C-terminally TAP-tagged CG4747.
Project description:The WWTR1(TAZ)-CAMTA1 and YAP1-TFE3 gene fusions are disease defining gene alterations for epithelioid hemangioendothelioma, a vascular cancer. The resultant fusion proteins fuse the C terminus of CAMTA1 and TFE3 in frame to the N terminus of TAZ and YAP, respectively. An unbiased BioID-mass spectrometry/RNAi screen identified YEATS2 and ZZZ3 as components of the Ada2a-containing histone acetyltransferase complex and key interactors of both TAZ-CAMTA1 and YAP-TFE3. An integrative NGS approach validating the chromatin occupancy of TAZ-CAMTA1 and YAP-TFE3 with distal regulatory elements, such as enhancer regions marked by the presence of H3K27ac marks. The altered transcriptional program of the fusion proteins owing to altered DNA binding as well as shifts in the chromatin landscape.
Project description:The essential histone variant H2A.Z affects various DNA-based biological processes by so far not well understood mechanisms. Using a comprehensive label-free quantitative mass spectrometry-based approach we identified the human H2A.Z nucleosome interactome providing further insights into H2A.Z’s regulatory functions. Besides histone modification writer, eraser and reader complexes we identified PWWP2A as a novel H2A.Z-nucleosome binder. PWWP2A binds unprecedented strong to chromatin through a concerted multivalent binding mode. Two internal protein regions separately allow H2A.Z-specificity and nucleosome interaction, whereas the PWWP domain mediates direct DNA binding. PWWP2A is found at euchromatic regions where it preferable binds to the H2A.Z-nucleosome-containing transcriptional start sites of transcribed genes. Cellular depletion of PWWP2A results in impaired proliferation caused by a mitotic delay likely due to deregulation of involved target genes. According with the strong cellular phenotype, knockdown of frog PWWP2A leads to severe developmental cranial facial defects arising from neural crest cell differentiation and migration problems. Together, this study identifies PWWP2A as an H2A.Z-specific multivalent chromatin binder and provides a novel link between H2A.Z, chromosome segregation and organ development.
Project description:The essential histone variant H2A.Z affects various DNA-based biological processes by so far not well understood mechanisms. Using a comprehensive label-free quantitative mass spectrometry-based approach we identified the human H2A.Z nucleosome interactome providing further insights into H2A.Z’s regulatory functions. Besides histone modification writer, eraser and reader complexes we identified PWWP2A as a novel H2A.Z-nucleosome binder. PWWP2A binds unprecedented strong to chromatin through a concerted multivalent binding mode. Two internal protein regions separately allow H2A.Z-specificity and nucleosome interaction, whereas the PWWP domain mediates direct DNA binding. PWWP2A is found at euchromatic regions where it preferable binds to the H2A.Z-nucleosome-containing transcriptional start sites of transcribed genes. Cellular depletion of PWWP2A results in impaired proliferation caused by a mitotic delay likely due to deregulation of involved target genes. According with the strong cellular phenotype, knockdown of frog PWWP2A leads to severe developmental cranial facial defects arising from neural crest cell differentiation and migration problems. Together, this study identifies PWWP2A as an H2A.Z-specific multivalent chromatin binder and provides a novel link between H2A.Z, chromosome segregation and organ development.
Project description:Cellular senescence is a tumor-suppressive program that involves chromatin reorganization and specific changes in gene expression that trigger an irreversible cell-cycle arrest. We combined quantitative mass spectrometry and ChIP deep-sequencing to identify changes in histone modification occurring during cellular senescence.
Project description:We report the usage of ChIP-mass spectrometry in identifying proteins and histone modifications involved in Drosophila dosage compensation. We identified a chromatin targeting factor, CG4747, that is involved in recognition of H3K36me3 and robust recruitment of the Drosophila MSL complex to its correct targets on the male X chromosome.