Project description:Genome-wide mapping of NuRD subunits, H3.3, and histone modifications in WT and H3.3 KD 3T3 MEFs. RNAseq data from WT and H3.3 KD cells.
Project description:Background. The histone variant H3.3 plays key roles in regulating chromatin states and transcription. However, the role of endogenous H3.3 in mammalian cells and during development has been less thoroughly investigated. To address this gap, we report the production and phenotypic analysis of mice and cells with targeted disruption of the H3.3-encoding gene, H3f3b. Results. H3f3b KO mice exhibit a semi-lethal phenotype traceable at least in part to defective cell division and chromosome segregation. H3f3b KO cells have widespread ectopic CENP-A protein localization suggesting one possible mechanism for defective chromosome segregation. KO cells have abnormal karyotypes and cell cycle profiles as well. The transcriptome and euchromatin-related epigenome were moderately affected by loss of H3f3b in MEFs with ontology most notably pointing to changes in chromatin regulatory and histone coding genes. Reduced numbers of H3f3b KO mice survive to maturity and almost all survivors from both sexes are infertile. Conclusions. Taken together, our studies suggest that endogenous mammalian histone H3.3 has important roles in regulating chromatin and chromosome functions that in turn are important for cell division, genome integrity, and development. Examination of H3K9Ac and H3K4me3 in wild-type and H3.3 null MEFs
Project description:Purpose: Pancreatic neuroendocrine tumors (PanNETs) have considerable malignant potential. Frequent somatic mutations and loss of DAXX protein expression have been frequently found in PanNETs. DAXX is known as a transcriptional repressor, however, molecular functions underlying loss of DAXX remain unclear in PanNETs. Experimental Design: We evaluated DAXX-knockdown (KD) and -knockout (KO) PanNET cells were analyzed for in vitro and vivo. The target genes were screened by microarray and chromatin immunoprecipitation (ChIP) assays for DAXX, histone H3.3 and H3K9me3 complex. Results: Microarray and ChIP analyses of DAXX-KD/KO identified 13 genes as the direct targets of DAXX transcriptional repressor. Among them, 5 genes were suppressed by DAXX/H3.3/H3K9me3 pathway. DAXX-KD/KO increased sphere forming activity, but it was suppressed by knockdown of the target gene. In xenograft models, tumorigenicity was significantly increased in DAXX-KO cells with high expression of the target. Clinically, higher recurrence was recognized in PanNETs with low expression of DAXX and high expression of the target than others. Conclusions: DAXX plays as a tumor suppressor and DAXX/H3.3 complex suppresses target genes by promoting H3K9me3 in PanNETs. DAXX and its target molecule might be effective biomarkers and therapeutic candidates.
Project description:We found that the incorporation of histone H3 variant H3.3 was impaired and the accumulation of ZMYND11, which specifically binds to H3.3K36me3, was decreased in NSD2 KO MEFs. About H3K36me2, the average gene body profiles of H3K36me2 showed preferential enrichment of H3K36me2 at the promoter and first half of the genic regions. We examined H3K36me2 mark in super enhancer regions using the ROSE super enhancer prediction program and identified of the 519 super enhancer islands of H3K36me2 in WT MEFs the H3K36me2 signals were decreased in NSD2 KO MEFs
Project description:Background. The histone variant H3.3 plays key roles in regulating chromatin states and transcription. However, the role of endogenous H3.3 in mammalian cells and during development has been less thoroughly investigated. To address this gap, we report the production and phenotypic analysis of mice and cells with targeted disruption of the H3.3-encoding gene, H3f3b. Results. H3f3b KO mice exhibit a semi-lethal phenotype traceable at least in part to defective cell division and chromosome segregation. H3f3b KO cells have widespread ectopic CENP-A protein localization suggesting one possible mechanism for defective chromosome segregation. KO cells have abnormal karyotypes and cell cycle profiles as well. The transcriptome and euchromatin-related epigenome were moderately affected by loss of H3f3b in MEFs with ontology most notably pointing to changes in chromatin regulatory and histone coding genes. Reduced numbers of H3f3b KO mice survive to maturity and almost all survivors from both sexes are infertile. Conclusions. Taken together, our studies suggest that endogenous mammalian histone H3.3 has important roles in regulating chromatin and chromosome functions that in turn are important for cell division, genome integrity, and development.
Project description:Mature oocyte cytoplasm can reprogram somatic cell nuclei to the pluripotent state through a series of sequential events including protein exchange between the donor nucleus and ooplasm, chromatin remodeling, and pluripotency gene reactivation. Maternal factors that are responsible for this reprogramming process remain largely unidentified. Here, we demonstrate that knockdown of histone variant H3.3 in mouse oocytes results in compromised reprogramming and down-regulation of key pluripotency genes; and this compromised reprogramming both for developmental potentials and transcription of pluripotency genes can be rescued by injecting exogenous H3.3 mRNA, but not H3.2 mRNA into oocytes in somatic cell nuclear transfer (SCNT) embryos. We show that maternal H3.3, and not H3.3 in the donor nucleus, is essential for successful reprogramming of somatic cell nucleus into the pluripotent state. Furthermore, H3.3 is involved in this reprogramming process by remodeling the donor nuclear chromatin through replacement of donor nucleus-derived H3 with de novo synthesized maternal H3.3 protein. Our study shows that H3.3 is a crucial maternal factor for oocyte reprogramming and provides a practical model to directly dissect the oocyte for its reprogramming capacity. Transcriptome sequencing of 4-cell NT embryos, Luciferase 4-cell SCNT embryos, 4-cell NT embryos_H3.3KD, 4-cell NT embryos_H3.3KD+H3.3mRNA, H3.3 KD + H3.2 mRNA SCNT embryos
Project description:Regions of H3.3 binding in WT and ATRX KO mouse ES cells were identified by ChIP seq Chip-seq experiements were performed in WT and ATRX KO E14 mouse ES cells
Project description:Histone variants can effect nucleosome stability or affect histone of DNA modifications. H3.3 is a major H3 histone variant that is incorporated into chromatin outside of S-phase in various eukaryotes. In animals, H3.3 is associated with active transcription and possibly maintenance of transcriptional memory. Plant H3.3, which evolved independently of animal H3.3, is much less well understood. We performed ChIP-chip using chromatin from rosette leaves of 35S:H3.3-YFP plants.
Project description:This project looks at the effect a chemical modulator targeting PI3Kα has on the phosphoproteome of PI3Kα-WT and PI3Kα-KO MEFs. PI3K signalling is a critical regulator of numerous cellular processes such as proliferation, apoptosis, migration, invasion, metabolism, cell growth and autophagy. The PI3K pathway is frequently hyperactivated in cancer, commonly due to activating mutations or via loss of the lipid phosphatases that negatively regulate the pathway. We have recently identified a new small molecule modulator of the PI3K pathway and have used an unbiased phosphoproteomics approach to examine the impact of this compound on signalling pathways in cells that are wild-type and knockout for PI3K. Immortalised mouse embryonic fibroblasts (MEFs) isolated from PI3Kα-WT and PI3Kα-KO embryos were treated with and without the modulator (5 µM), exploring early (15 min) and late (4 h) time points. Insulin is a well-characterised activator of PI3K. Therefore, PI3Kα-WT MEFs were also treated with insulin (100 nM) as a positive control to compare with the PI3K modulator.