Project description:H3.3-mediated paternal chromatin remodeling is essential for the development of preimplantation embryos and the activation of the paternal genome during embryogenesis.
Project description:Derepression of chromatin-mediated transcriptional repression of paternal and maternal genomes is considered the first major step that initiates zygotic gene expression after fertilization. The histone variant H3.3 is present in both male and female gametes and is thought to be important for remodeling the paternal and maternal genomes for activation during both fertilization and embryogenesis. However, the underlying mechanisms remain poorly understood. Using our H3.3B-HA-tagged mouse model, engineered to report H3.3 expression in live animals and to distinguish different sources of H3.3 protein in embryos, we show here that sperm-derived H3.3 (sH3.3) protein is removed from the sperm genome shortly after fertilization and extruded from the zygotes via the second polar bodies (PBII) during embryogenesis. We also found that the maternal H3.3 (mH3.3) protein is incorporated into the paternal genome as early as 2 h postfertilization and is detectable in the paternal genome until the morula stage. Knockdown of maternal H3.3 resulted in compromised embryonic development both of fertilized embryos and of androgenetic haploid embryos. Furthermore, we report that mH3.3 depletion in oocytes impairs both activation of the Oct4 pluripotency marker gene and global de novo transcription from the paternal genome important for early embryonic development. Our results suggest that H3.3-mediated paternal chromatin remodeling is essential for the development of preimplantation embryos and the activation of the paternal genome during embryogenesis.
Project description:This SuperSeries is composed of the following subset Series: GSE16882: Histone H1 binding is restricted by histone variant H3.3 (Nucleosome) GSE16883: Histone H1 binding is restricted by histone variant H3.3 (DamID) GSE16884: Histone H1 binding is restricted by histone variant H3.3 (Expression) GSE19764: Histone H1 binding is restricted by histone variant H3.3 (FAIRE) Refer to individual Series
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:The incorporation of histone H3 variants has been implicated in the epigenetic memory of cellular state. Using genome editing with zinc finger nucleases to tag endogenous H3.3, we report genome-wide profiles of H3 variants in mammalian embryonic stem (ES) cells and neuronal precursor cells. Genome-wide patterns of H3.3 are dependent on amino acid sequence, and change with cellular differentiation at developmentally regulated loci. The H3.3 chaperone Hira is required for H3.3 enrichment at active and repressed genes. Strikingly, Hira is not essential for localization of H3.3 at telomeres and many transcription factor binding sites. Immunoaffinity purification and mass spectrometry reveal that the proteins Atrx and Daxx associate with H3.3 in a Hira-independent manner. Atrx is required for Hira-independent localization of H3.3 at telomeres, and for the repression of telomeric RNA. Our data demonstrate that multiple and distinct factors are responsible for H3.3 localization at specific genomic locations in mammalian cells. Crosslinking ChIP-seq: Examination of 1 histone variant (H3.3), 2 histone modifications, and Serine-5 phosphorylated RNA polymerase in 2 different cell types (H3.3-HA ES samples 1-4, and H3.3-HA NPC samples 7-10). Examination of 1 histone variant (H3.2), and one histone modification (H3K36me3) in 2 different cell types (H3.2-HA ES samples 5-6, and H3.2-HA NPC samples 11-12). Examination of 1 histone variant (H3.3), input control, and one histone modification (H3K36me3) in one cell type (H3.3-HA hybrid ES, samples 13-15). Examination of 1 histone variant (H3.1S31), input control, and one histone modification (H3K36me3) in one cell type (H3.1S31-HA hybrid ES, samples 16-18). Native ChIP-seq: Examination of 1 histone variant (H3.3), input control, and one histone modification (H3K4me3) in one cell type (H3.3-HA ES, samples 19-21). Examination of 1 histone variant (H3.2), input control, and two histone modifications (H3K4me3 and H3K27me3) in one cell type (H3.2-HA ES, samples 22-25). Examination of 1 histone variant (H3.3), input control, and two histone modifications (H3K4me1 and H3K36me3) in one cell type (H3.3-EYFP ES, samples 26-29). Examination of 1 histone variant (H3.3), input control, and two histone modifications (H3K4me1 and H3K36me3) in one cell type (Hira -/- H3.3-EYFP ES, samples 30-33). Examination of 1 histone variant (H3.3) and input control in one cell type (Atrxflox H3.3-EYFP ES, samples 34-37). Examination of HA antibody background in one cell type (wild-type ES, sample 38).
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.
Project description:We developed a system to study the DNA replication-independent turnover nucleosomes containing the histone variant H3.3 in mammalian cells. By measuring the genome-wide incorporation of H3.3 at different time points following epitope-tagged H3.3 expression, we find three categories of H3.3-nucleosome turnover in vivo: rapid turnover, intermediate turnover and, specifically at telomeres, slow turnover. Our data indicate that H3.3-containing nucleosomes at enhancers and promoters undergo a rapid turnover that is associated with active histone modification marks including H3K4me1, H3K4me3, H3K9ac, H3K27ac and the histone variant H2A.Z. The rate of turnover is negatively correlated with H3K27me3 at regulatory regions and with H3K36me3 at gene bodies. Examination of incorporation dynamics of histone variant H3.3
Project description:This SuperSeries is composed of the following subset Series: GSE36626: Dynamic Deposition of the Histone H3.3 Variant Accompanies Developmental Remodeling of Arabidopsis Transcriptome (mRNA-Seq) GSE36629: Dynamic Deposition of the Histone H3.3 Variant Accompanies Developmental Remodeling of Arabidopsis Transcriptome (ChIP-Seq) Refer to individual Series
Project description:Poor parental health can influence the development and eventual health outcomes of their offspring. Many studies have detailed the maternal role yet a father’s health requires further examination as his poor nutritional status has also been shown to have negative consequences on fetal development and impact the long-term health of his offspring. The present study examined how preimplantation embryo development was altered by sub-optimal paternal diet, with specific focus on sperm- and seminal plasma-mediated mechanisms. To address this, male mice were fed a diet to model either under (low protein diet (LPD)) or over (high fat/sugar ‘Western’ diet (WD)) nutrition, LPD or WD supplemented with methyl-donors or a control diet (CD) before mating. Embryo development was assessed using in vitro time-lapse imaging of preimplantation embryos which revealed a significant increase in embryo development rates in all experimental groups when compared to CD embryos. Further analysis of the semen revealed a significant number of differentially expressed seminal plasma proteins in all groups (LPD: 13, MD-LPD: 27, WD: 24, MD-WD: 19) when compared to control. This study highlights a role for paternal nutritional status influencing embryonic development and the maternal reproductive tract via changes to his metabolic and reproductive health. These findings demonstrate potential direct (sperm-mediated) and indirect (seminal plasma-mediated) pathways in which a father's poor diet could shape the long-term health of his offspring
Project description:The acquisition of germination and post-embryonic developmental ability during seed maturation is vital for seed vigor, an important trait for plant propagation and crop production. How seed vigor is established in seeds is still poorly understood. Here, we report the crucial function of Arabidopsis histone variant H3.3 in chromatin structure regulation that endows seeds with post-embryonic developmental potentials. H3.3 is not essential for seed formation, but the loss of H3.3 results in severely impaired germination and post-embryonic development. H3.3 exhibits a seed-specific 5’ gene end distribution, which facilities chromatin opening in seeds. During germination, this H3.3-established chromatin accessibility is essential for proper gene transcriptional regulation. Moreover, H3.3 is constantly loaded at the 3’ gene end and restricts chromatin accessibility to prevent cryptic transcription and protect gene body DNA methylation. Our results suggest a fundamental role of H3.3 in initiating chromatin opening at regulatory regions in seed to license the embryonic to post-embryonic transition.