Similar Datasets
Project description:Somatic cell nuclear transfer (SCNT) in mammals is an inefficient process that is frequently associated with abnormal phenotypes, especially in placentas. Recent studies demonstrated that mouse SCNT placentas completely lack histone methylation (H3K27me3)-dependent imprinting, but how it affects placental development remains unclear. Here, we provide evidence that the loss of H3K27me3 imprinting is responsible for abnormal placental enlargement and low birth rates following SCNT, through upregulation of imprinted miRNAs. When we restore the normal paternal expression of H3K27me3-dependent imprinted genes (Sfmbt2, Gab1, and Slc38a4) in SCNT placentas by maternal knockout, the placentas remain enlarged. Intriguingly, correcting the expression of clustered miRNAs within the Sfmbt2 gene ameliorates the placental phenotype. Importantly, their target genes, which are confirmed to cause SCNT-like placental histology, recover their expression level. The birth rates increase about twofold. Thus, we identify loss of H3K27me3 imprinting as an epigenetic error that compromises embryo development following SCNT.
| S-EPMC7195362 | biostudies-literature
Project description:Abnormal placentation in cloned animals remains an unsolved problem. We demonstrated the involvement of micro RNAs (miRNAs) in the abnormal enlargement (hyperplasia) of placentas in cloned mice. Using a comparative transcriptome analysis of cloned placentas, we noted the consistent upregulation of clustered miRNAs within Sfmbt2, a paternally expressed imprinted gene. This region was biallelically activated by loss of imprinting (LOI) in cloned placentas. Deletion of the maternal allele of the whole miRNA cluster resulted in the correction of their expression levels and upregulation of their putative target genes with antitumor or apoptotic functions. Consequently, the placental size was reduced to the normal level and histology was ameliorated. In contrast, correcting the expression of the LOI genes (Sfmbt2, Gab1, and Scl38a4) in cloned placentas had no impact on placental size. Thus, we identified that LOI of clustered miRNAs within Sfmbt2 in cloned placentas was the major cause of abnormal placental enlargement.
2020-02-29 | GSE129541 | GEO
Project description:Abnormal placentation in cloned animals remains an unsolved problem. We demonstrated the involvement of micro RNAs (miRNAs) in the abnormal enlargement (hyperplasia) of placentas in cloned mice. Using a comparative transcriptome analysis of cloned placentas, we noted the consistent upregulation of clustered miRNAs within Sfmbt2, a paternally expressed imprinted gene. This region was biallelically activated by loss of imprinting (LOI) in cloned placentas. Deletion of the maternal allele of the whole miRNA cluster resulted in the correction of their expression levels and upregulation of their putative target genes with antitumor or apoptotic functions. Consequently, the placental size was reduced to the normal level and histology was ameliorated. In contrast, correcting the expression of the LOI genes (Sfmbt2, Gab1, and Scl38a4) in cloned placentas had no impact on placental size. Thus, we identified that LOI of clustered miRNAs within Sfmbt2 in cloned placentas was the major cause of abnormal placental enlargement.
2020-02-29 | GSE129939 | GEO
Project description:Loss of H3K27me3 imprinting in the Sfmbt2 miRNA cluster causes enlargement of cloned mouse placentas
| PRJNA533233 | ENA
Project description:Loss of H3K27me3 imprinting in the Sfmbt2 miRNA cluster causes enlargement of cloned mouse placentas
| PRJNA533508 | ENA
Project description:Loss of H3K27me3 imprinting in the Sfmbt2 miRNA cluster causes enlargement of cloned mouse placentas
| PRJNA531686 | ENA
Project description:Genomic imprinting is essential for mammalian development. Recent studies have revealed that maternal histone H3 Lys27 trimethylation (H3K27me3) can mediate DNA methylation-independent genomic imprinting. However, the regulatory mechanisms and functions of this new imprinting mechanism are largely unknown. Here we demonstrate that maternal Eed, an essential component of the Polycomb group complex 2 (PRC2), is required for establishing H3K27me3 imprinting. We found that all H3K27me3-imprinted genes, including Xist, lose their imprinted expression in Eed maternal knockout (matKO) embryos, resulting in male-biased lethality. Surprisingly, although maternal X-chromosome inactivation (XmCI) occurs in Eed matKO embryos at preimplantation due to loss of Xist imprinting, it is resolved at peri-implantation. Ultimately, both X chromosomes are reactivated in the embryonic cell lineage prior to random XCI, and only a single X chromosome undergoes random XCI in the extraembryonic cell lineage. Thus, our study not only demonstrates an essential role of Eed in H3K27me3 imprinting establishment but also reveals a unique XCI dynamic in the absence of Xist imprinting.
| S-EPMC6295166 | biostudies-literature
Project description:Genomic imprinting leads to mono-allelic expression of genes based on parent of origin. Therian mammals and angiosperms evolved this mechanism in nutritive tissues, the placenta, and endosperm, where maternal and paternal genomes are in conflict with respect to resource allocation. We used RNA-seq to analyze allelic bias in the expression of 91 known imprinted genes in term human placentas from a prospective cohort study in Mali. A large fraction of the imprinted exons (39%) deviated from mono-allelic expression. Loss of imprinting (LOI) occurred in genes with either maternal or paternal expression bias, albeit more frequently in the former. We characterized LOI using binomial generalized linear mixed models. Variation in LOI was predominantly at the gene as opposed to the exon level, consistent with a single promoter driving the expression of most exons in a gene. Some genes were less prone to LOI than others, particularly lncRNA genes were rarely expressed from the repressed allele. Further, some individuals had more LOI than others and, within a person, the expression bias of maternally and paternally imprinted genes was correlated. We hypothesize that trans-acting maternal effect genes mediate correlated LOI and provide the mother with an additional lever to control fetal growth by extending her influence to LOI of the paternally imprinted genes. Limited evidence exists to support associations between LOI and offspring phenotypes. We show that birth length and placental weight were associated with allelic bias, making this the first comprehensive report of an association between LOI and a birth phenotype.
| S-EPMC6993844 | biostudies-literature
Project description:Animal cloning can be achieved through somatic cell nuclear transfer (SCNT), although the live birth rate is relatively low. Recent studies have identified H3K9me3 in donor cells and abnormal Xist activation as epigenetic barriers that impede SCNT. Here we overcome these barriers using a combination of Xist knockout donor cells and overexpression of Kdm4 to achieve more than 20% efficiency of mouse SCNT. However, post-implantation defects and abnormal placentas were still observed, indicating that additional epigenetic barriers impede SCNT cloning. Comparative DNA methylome analysis of IVF and SCNT blastocysts identified abnormally methylated regions in SCNT embryos despite successful global reprogramming of the methylome. Strikingly, allelic transcriptomic and ChIP-seq analyses of pre-implantation SCNT embryos revealed complete loss of H3K27me3 imprinting, which may account for the postnatal developmental defects observed in SCNT embryos. Together, these results provide an efficient method for mouse cloning while paving the way for further improving SCNT efficiency.
| S-EPMC6326833 | biostudies-literature
Project description:Mammalian sperm and oocytes have different epigenetic landscapes and are organized in different fashions. After fertilization, the initially distinct parental epigenomes become largely equalized with the exception of certain loci, including imprinting control regions. How parental chromatin becomes equalized and how imprinting control regions escape from this reprogramming is largely unknown. Here we profile parental allele-specific DNase I hypersensitive sites in mouse zygotes and morula embryos, and investigate the epigenetic mechanisms underlying these allelic sites. Integrated analyses of DNA methylome and tri-methylation at lysine 27 of histone H3 (H3K27me3) chromatin immunoprecipitation followed by sequencing identify 76 genes with paternal allele-specific DNase I hypersensitive sites that are devoid of DNA methylation but harbour maternal allele-specific H3K27me3. Interestingly, these genes are paternally expressed in preimplantation embryos, and ectopic removal of H3K27me3 induces maternal allele expression. H3K27me3-dependent imprinting is largely lost in the embryonic cell lineage, but at least five genes maintain their imprinted expression in the extra-embryonic cell lineage. The five genes include all paternally expressed autosomal imprinted genes previously demonstrated to be independent of oocyte DNA methylation. Thus, our study identifies maternal H3K27me3 as a DNA methylation-independent imprinting mechanism.
| S-EPMC9674007 | biostudies-literature