Analysis of mouse monozygotic twin blastocysts produced in two different culture media
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ABSTRACT: Following fertilization in mammals, it is generally accepted that totipotent cells are exclusive to the zygote and to each of the two blastomeres originating from the first mitotic division. We counter that this classic view needs to be revised, because we have presented compelling evidence the sister blastomeres are both totipotent in only a subset of 2-cell stage mouse embryos (PMID 28811525). Building on our previous findings, we here ask the question if the differences between sister blastomeres can be modulated experimentally. To this end, we separate the sister blastomeres, yielding monozygotic twins. We culture these twins in two different media (GM501 vs. Sage 1 step), to see if the mRNA ratios of twin blastocysts lie more far apart from each other when culture took place in different media as compared to culture in the same medium (GSE90674). Transcriptome analysis followed by intra-pair mRNA ratio analysis revealed differences between the blastocysts of the same monozygotic pair. Some of the differences were sensitive to the choice of culture conditions, while other differences were insensitive.
Project description:Upon 2-cell embryo splitting, individual blastomeres were cultured in KSOM(aa) medium and developed into blastocysts, which were compared and contrasted with each other respecting pair associations (e.g. twin vs cotwin) Transcriptome analysis revelaled minimal differences between twins and unmanipulated controls, in contrast to larger differences between twins and cotwins; these differences are mainly related to the epiblast lineage
Project description:Following fertilization in mammals, it is generally accepted that totipotent cells are exclusive to the zygote and to each of the two blastomeres originating from the first mitotic division. We counter that this classic view needs to be revised, because we have presented compelling evidence that the sister blastomeres are both totipotent in only a subset of 2-cell stage mouse embryos (PMID 28811525). Building on our previous findings, we here ask the question if the interblastomere differences depend - at least in part - on the contribution of sperm, since the area of sperm entry is inherited preferentially by one blastomere. To this end, we created sister 2-cell stage blastomeres without sperm entry point, by parthenogenesis. We compare the transcriptomes of the sister blastomeres, to see if the interblastomere mRNA differences observed after fertilization (GSE94050) are still there when the sperm entry point is missing.
Project description:The present study examined the relationship between genome-wide methylation differences and variations in brain structures involved in the development of attention-deficit hyperactivity disorder (ADHD). We used monozygotic twins discordant for ADHD to identify candidate DNA methylation sites involved in the development of ADHD. Two pairs of MZ twins discordant for ADHD were recruited from the Department of Child and Adolescent Psychological Medicine at the University of Fukui Hospital. The twins were 9-year-old males (pair 1) and 16-year-old females (pair 2). Genomic DNA was collected from saliva samples, and the DNA was then whole-genome amplified, fragmented, and hybridized to the Human MethylationEPIC BeadChip.
Project description:It remains an open question when and how the first cell fate decision is made in mammals. Using deep single-cell RNA-seq of matched sister blastomeres, we report highly reproducible interblastomere differences among ten 2-cell and five 4-cell mouse embryos. Inter-blastomere gene expression differences dominated between-embryo differences and noises, and were sufficient to cluster sister blastomeres into distinct groups. Dozens of protein-coding genes exhibited reproducible bimodal expression in sister blastomeres (0 vs. 1e3-1e6 of FPKM), which cannot be explained by random fluctuations. The protein expression of one of these bimodal genes, Gadd45a, exhibited clear inter-blastomeric contrasts. We traced some of the bimodal mRNA expressions to embryonic genome activation, and others to blastomere-specific RNA depletion. Inter-blastomere differences created co-expression gene networks that were much stronger and larger than those that can be possibly created by random noises. The highly correlated gene pairs at the 4-cell overlapped with those showing the same directions of differential expression between inner cell mass (ICM) and trophectoderm (TE). These data substantiate the hypothesis of inter-blastomere differences in 2- and 4-cell mouse embryos, and associate these differences with ICM/TE differences. 9 zygotes, 10 2-cell, and 5 4-cell mouse (C57BL/6) embryos were collected and multi-cell embryos were separated into blastomeres. 4 inner cell mass (ICM) and 3 trophectoderm (TE) samples are also extracted from mouse blastocysts. Transcriptome profiles for all samples are obtained via Smart-seq protocol.
Project description:This study investigated differences in serum exosome microRNA-cargo, obtained from healthy postmenopausal monozygotic twins (n=10 pairs), from which the other sister was using estrogen-based hormone replacement therapy (HRT) and the other was not under treatment. In addition, premenopausal women (n=8) with natural hormonal status were included in the study. This study gave new information about the exomiR messaging and its sensitivity to age and HRT.
Project description:Human intelligence demonstrates one of the highest heritabilities among human quantitative traits. Phenotypically discordant monozygotic twins provide a way to identify loci reponsible for the phenotypical differences. We performed comprehensive DNA methylation analysis in monozygotic twins manifesting differences in IQ scores. Genes with significantly different methylation status are considered as candidates related to human intelligence.
Project description:Peripheral blood from thirty-four monozygotic twin subjects from the general population (n = 17 twin pairs) was collected for epigenomic analysis via Illumina Infinium HumanMethylation450 Beadchip. All subjects were screened for DSM-IV based criteria for both current and lifetime psychiatric disorders. Out of 17 twin pairs, there were: 7 healthy twin pairs where none of the twins of a pair met criteria for any DSM-IV disorder; 6 discordant twin pairs where only one of the twins of each pair met diagnostic criteria; and 4 concordant twin pairs where both twins of a pair met clinical DSM-IV based criteria.
Project description:Human intelligence demonstrates one of the highest heritabilities among human quantitative traits. Phenotypically discordant monozygotic twins provide a way to identify loci responsible for normal-range intelligence. We conducted array-based genome-wide gene expression analysis aiming to identify genes displaying significant difference among monozygotic twin pairs manifesting between-co-twins IQ differences.
Project description:Upon 2-cell embryo splitting, individual blastomeres were compared and contrasted with each other respecting pair associations (e.g. blastomere '1a' and '1b' of embryo 1, '2a' and '2b' of embryo 2, and so forth) Transcriptome analysis followed by cluster analysis (Ward) was able to match a minority of the blastomeres with the correct sister blastomere
Project description:Autism spectrum disorder(ASD) is a complex neurodevelopmental disorder. Aberrant DNA methylation has been observed in ASD but the mechanisms remain largely unknown. Here, we employed discordant monozygotic twins to investigate the contribution of DNA methylation to ASD etiology. Genome-wide DNA methylation analysis was performed using samples obtained from five pairs of ASD-discordant monozygotic twins, which revealed a total of 2397 differentially methylated genes. Further, such gene list was annotated with Kyoto Encyclopedia of Genes and Genomes and demonstrated predominant activation of neurotrophin signaling pathway in ASD-discordant monozygotic twins. The methylation of SH2B1 gene was further confirmed in the ASD-discordant, ASD-concordant monozygotic twins, and a set of 30 pairs of sporadic case-control by bisulfite-pyrosequencing. The results showed that there was a greater DNA methylation difference in ASD-discordant monozygotic twins than ASD-concordant monozygotic twins. Further, verification of the Chr.16:28856743 of SH2B1 showed significant differences in DNA methylation between case and control. These results suggest abnormal methylation of SH2B1 is associated with ASD etiology. Our data suggest that it might be worthwhile to further explore the functions of SH2B1 and related genes of neurotrophin signaling pathway in ASD.