Project description:Epigenetic homogeneity underlies sperm programming for embryonic transcription single-ended ChIP-Seq libraries from sperm, egg extract (-geminin) treated sperm, egg extract (+geminin) treated sperm, and St 7 embryos with antibody for H3Kme3, H3K27me3, 3 replicates for each histone modification pull-down
Project description:Sperm contributes genetic and epigenetic information to the embryo to efficiently support development. However, the mechanism underlying such developmental competence remains elusive. Here, we investigated whether all sperm cells have a common epigenetic configuration that primes transcriptional program for embryonic development. We show for the first time that remodelling of histones during spermiogenesis results in the retention of methylated histone H3 at the same genomic location in every sperm cell. This homogeneously methylated fraction of histone H3 in the sperm genome is maintained during early embryonic replication. Such methylated histone fraction resisting postfertilisation reprogramming marks developmental genes whose expression is perturbed upon experimental reduction of histone methylation. A similar homogeneously methylated histone H3 fraction is detected in human sperm. Altogether, we uncover a conserved mechanism of paternal epigenetic information transmission to the embryo through the homogeneous retention of methylated histone in a sperm cells population.
Project description:The WGBS data was published in PMID: 31393794 and the sequencing data from WGBS and MCC-Seq have been submitted to the European Genome-phenome Archive under the accession number EGAS00001003617. The paternal environment including stress, diet and toxicants has been linked to infertility and negative outcomes for offspring such as birth defects and adult onset of disease. Such effects may be transmitted via sperm through epigenetic mechanisms. To date, in depth profiling of the sperm epigenome in men has been limited. Our objective was to characterize the sperm profile of histone H3 lysine 4 tri-methylation (H3K4me3) from a reference population of men and relate this to sperm DNA methylation. ChIP-seq targeting H3K4me3 was performed on sperm from a representative reference population of 30 men and then overlapped with whole genome bisulfite sequencing (WGBS) data from the same men. Our analysis revealed that H3K4me3 is localized throughout the genome and at genes for fertility and development. Remarkably, enrichment was also found at regions that escape epigenetic reprogramming in primordial germ cells, embryonic enhancers and SINEs. The level of H3K4me3 in sperm associates with the degree of gene expression in embryo development. We find significant overlap in H3K4me3 and DNA methylation throughout the genome suggesting potential for the development of a personalized medicine approach for the assessment of fertility, lifestyle and environmental exposures.
Project description:Obesity is a global rising problem with epidemiological dimension. Obese parents can have programming effects on their offspring leading to obesity and associated diseases in later life. This constitutes a vicious circle. Epidemiological data and studies in rodents demonstrated differential programming effects in male and female offspring, but the timing of their developmental origin is not known. This study investigated if sex-specific programming effects of parental obesity can already be detected in the pre-implantation period. Diet induced obese male or female mice were mated with normal-weight partners and blastocysts were recovered. Gene expression profiling revealed sex-specific responses of the blastocyst transcriptome to maternal and paternal obesity. The changes in the transcriptome of male blastocysts were more pronounced than those of female blastocysts, with a stronger impact of paternal than of maternal obesity. The sperm of obese mice revealed an increased abundance of several miRNAs compared to lean mice. Our study indicates that sex-specific programming effects of parental obesity already start in the pre‑implantation period and reveals specific alterations of the sperm miRNA profile as mechanistic link to programming effects of paternal obesity.
Project description:Using the frog Xenopus laevis as a model system we profile epigenetic features of sperm and spermatid to study how they relate to gene expression in embryos. We observe that sperm is epigenetically programmed to regulate embryonic gene expression. By comparing the development of sperm- and spermatid-derived frog embryos we show that the programming of sperm for successful development relates to its ability to regulate transcription of a set of developmentally important genes. During spermatid maturation into sperm, these genes lose H3K4me2/3 and retain H3K27me3 marks. Experimental removal of these epigenetic marks, at fertilization, deregulates gene expression in the resulting embryos in a paternal chromatin dependent manner. This demonstrates that epigenetic instructions delivered by the sperm at fertilization are required for correct regulation of gene expression in the future embryos. The epigenetic mechanisms of developmental programming revealed here are likely to relate to the mechanisms involved in transgenerational transmission of acquired traits. 48 samples, single-ended ChIP-seq libraries from sperm- and spermatid-derived haploid embryos pulling down H3K4me2, H3K4me3, H3K27me3 and H3K9me3, 3 replicates for each histone modification pull-down. 14 samples of both single-ended and pair-ended RNA-seq libraries for sperm- and spermatid-derived embryos. 3 replicates of single-ended RNA-seq libraries for spermatid cells. 22 samples of single-ended RNA-seq form sperm- and spermatid-derived embryos overexpressing Kdm5b 16 samples of single-ended RNA-seq form sperm- and spermatid-derived embryos overexpressing Kdm6b 6 samples of single-ended MNase-seq from sperm and spermatid chromatin 12 samples of MBD-seq from sperm and spermatid chromatin
Project description:Using the frog Xenopus laevis as a model system we profile epigenetic features of sperm and spermatid to study how they relate to gene expression in embryos. We observe that sperm is epigenetically programmed to regulate embryonic gene expression. By comparing the development of sperm- and spermatid-derived frog embryos we show that the programming of sperm for successful development relates to its ability to regulate transcription of a set of developmentally important genes. During spermatid maturation into sperm, these genes lose H3K4me2/3 and retain H3K27me3 marks. Experimental removal of these epigenetic marks, at fertilization, deregulates gene expression in the resulting embryos in a paternal chromatin dependent manner. This demonstrates that epigenetic instructions delivered by the sperm at fertilization are required for correct regulation of gene expression in the future embryos. The epigenetic mechanisms of developmental programming revealed here are likely to relate to the mechanisms involved in transgenerational transmission of acquired traits.
Project description:The potential that adolescent chemotherapy can impact the epigenetic programming of the germ line to influence later life adult fertility and promote epigenetic inheritance was investigated. Adult males approximately ten years after pubertal exposure to chemotherapy were compared to adult males with no previous exposure. Sperm were collected to examine differential DNA methylation regions (DMR) between the exposed and control populations. A statistically significant signature of DMRs was identified in the chemotherapy exposed male sperm. The DMRs, termed epimutations, were found in CpG desert regions of primarily 1 kilobase size. Gene associations and correlations to genetic mutations (copy number variation) were also investigated. Observations indicate adolescent chemotherapy exposure can promote epigenetic alterations that persist in later life. The germline (i.e. sperm) epimutations identified suggest chemotherapy has the potential to promote epigenetic inheritance to the next generation.
Project description:Preconception environmental conditions have been demonstrated to shape sperm epigenetics and subsequently offspring health and development. Our previous findings in humans showed that urinary anti-androgenic phthalate metabolites in males were associated with altered sperm methylation and blastocyst-stage embryo development. To corroborate this, we examined the effect of preconception exposure to di(2-ethylhexyl) phthalate (DEHP) on genome-wide DNA methylation and gene expression profiles in mice. We found that male preconception DEHP exposure resulted in 704 differentially methylated regions (DMRs; q-value < 0.05; ³ 10% methylation change) in sperm, 1,716 DMRs in embryonic, and 3,181 DMRs in extra-embryonic tissue. Of these, 29 DMRs overlapped between sperm and F1 tissues, half of which showed concordant methylation changes between F0 and F1 generations. F1 transcriptomes at E7.5 were also altered by male preconception DEHP exposure including developmental gene families such as Hox, Gata, and Sox. Additionally, gene ontology analyses of DMRs and differentially expressed genes showed enrichment of multiple developmental processes including embryonic development, pattern specification and morphogenesis.