Multipolar zygotic divisions are characterized by parental genome segregation errors
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PROVIDER: PRJNA755972 | ENA |
REPOSITORIES: ENA
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Project description:Multipolar zygotic divisions are characterized by parental genome segregation errors
| PRJEB46925 | ENA
Project description:The first mitotic division causes both parental genomes present in the zygote to segregate into two biparental diploid daughter cells. This fundamental tenet was challenged by the observation that blastomeres with different genome ploidy and distinct parental genotypes can coexist within individual embryos. We hypothesized that whole parental genomes can segregate into distinct blastomere lines during the multipolar division of the zygote, a phenomenon referred to as “heterogoneic” cell division. Here, we provide evidence of genome-wide segregation errors in two human blastocysts and further pinpoint its origin in a bovine model by mapping the genomic landscape of 82 blastomeres from 25 embryos that underwent multipolar division at the zygote stage using genome-wide SNP arrays and sequencing. In most embryos, the coexistence of androgenetic and diploid or polyploid blastomeres with or without anuclear blastomeres, androgenetic and anuclear blastomeres, and androgenetic and gynogenetic blastomeres within the same embryo provided proof that multipolar zygotic division coincides with heterogoneic segregation of the parental genome. By mapping the segregational origin of the genomic content, we deduced distinct segregation mechanisms underlying heterogoneic cell division including segregation by a tripolar spindle, the pronuclear extrusion of a paternal genome and, the operation of an ectopic paternal or private parental spindles. Polyspermic embryos expel excessive paternal genomes resulting in an androgenetic or polyploid blastomere. Confirming the results in human blastocysts we found genome-wide segregation errors to persist in bovine blastocysts.
2021-08-21 | GSE182345 | GEO
Project description:The first mitotic division causes both parental genomes present in the zygote to segregate into two biparental diploid daughter cells. This fundamental tenet was challenged by the observation that blastomeres with different genome ploidy and distinct parental genotypes can coexist within individual embryos. We hypothesized that whole parental genomes can segregate into distinct blastomere lines during the multipolar division of the zygote, a phenomenon referred to as “heterogoneic†cell division. Here, we provide evidence of genome-wide segregation errors in two human blastocysts and further pinpoint its origin in a bovine model by mapping the genomic landscape of 82 blastomeres from 25 embryos that underwent multipolar division at the zygote stage using genome-wide SNP arrays and sequencing. In most embryos, the coexistence of androgenetic and diploid or polyploid blastomeres with or without anuclear blastomeres, androgenetic and anuclear blastomeres, and androgenetic and gynogenetic blastomeres within the same embryo provided proof that multipolar zygotic division coincides with heterogoneic segregation of the parental genome. By mapping the segregational origin of the genomic content, we deduced distinct segregation mechanisms underlying heterogoneic cell division including segregation by a tripolar spindle, the pronuclear extrusion of a paternal genome and, the operation of an ectopic paternal or private parental spindles. Polyspermic embryos expel excessive paternal genomes resulting in an androgenetic or polyploid blastomere Confirming the results in human blastocysts we found genome-wide segregation errors to persist in bovine blastocysts.
| EGAS00001005543 | EGA
Project description:Asymmetric cell divisions (ACDs) generate two daughter cells with identical genetic information but distinct cell fates. Epigenetic mechanisms are crucial for cell fate specification, and it remains unclear how epigenetic information is inherited. Here, we report asymmetric segregation of the nucleosome remodeling and deacetylase complex (NuRD) during ACDs in Caenorhabditis elegans. NuRD is enriched to chromosomes of the future surviving but not apoptotic daughter cell, whereas NuRD evenly distributes to two viable siblings. Disruption of ACDs causes symmetric NuRD inheritance, and an ectopic gain of NuRD in apoptotic daughters allows cell survival and differentiation. Lack of NuRD upregulates the expression of the vital cell death-inducing gene egl-1 by increasing H3K27 acetylation on the egl-1 locus, which activates the EGL-1-CED-9-CED-4-CED-3 pathway to promote apoptosis. We propose that biased NuRD segregation during ACDs provides a previously unrecognized yet common mechanism for asymmetrically partitioning epigenetic information that contributes to binary cell fate decisions.
2022-12-30 | GSE167379 | GEO
Project description:Asymmetric Segregation of the Nucleosome Remodeling and Deacetylase Complex during Asymmetric Cell Divisions
| PRJNA704418 | ENA
Project description:During animal development, a fertilized egg is initially under the control of maternal products and only starts zygotic transcription after several cell divisions. In animals such as Xenopus, zebrafish and Drosophila, a massive increase in zygotic transcription occurs during the mid-blastula transition (MBT), when cells shift from rapid, synchronous cell divisions without gap phases to prolonged asynchronous divisions. Before MBT, only a few so-called pre-MBT genes are expressed. How transcription is set up during these early stages is poorly understood. For example, paused RNA Polymerase (Pol II) is frequently found at developmental control genes in mammalian embryonic stem cells and Drosophila embryos but when Pol II pausing is first established in the embryo is unknown. We have analyzed the genome-wide Pol II occupancy during the maternal-to-zygotic transition in hand-staged Drosophila embryos. The results show that massive Pol II recruitment and pausing is established during MBT. The ~100 genes that are transcribed before MBT are particularly short, consistent with a need for rapid transcription during these early cell divisions. Remarkably, most of these genes are transcribed without Pol II pausing and this correlates with a TATA-enriched promoter type. This suggests that distinct strategies are used for activation in the early Drosophila embryo and this may reflect general dynamic properties of promoters used throughout development. Mnase-seq in staged Drosophila embryos
2013-07-26 | E-GEOD-41686 | biostudies-arrayexpress
Project description:During animal development, a fertilized egg is initially under the control of maternal products and only starts zygotic transcription after several cell divisions. In animals such as Xenopus, zebrafish and Drosophila, a massive increase in zygotic transcription occurs during the mid-blastula transition (MBT), when cells shift from rapid, synchronous cell divisions without gap phases to prolonged asynchronous divisions. Before MBT, only a few so-called pre-MBT genes are expressed. How transcription is set up during these early stages is poorly understood. For example, paused RNA Polymerase (Pol II) is frequently found at developmental control genes in mammalian embryonic stem cells and Drosophila embryos but when Pol II pausing is first established in the embryo is unknown. We have analyzed the genome-wide Pol II occupancy during the maternal-to-zygotic transition in hand-staged Drosophila embryos. The results show that massive Pol II recruitment and pausing is established during MBT. The ~100 genes that are transcribed before MBT are particularly short, consistent with a need for rapid transcription during these early cell divisions. Remarkably, most of these genes are transcribed without Pol II pausing and this correlates with a TATA-enriched promoter type. This suggests that distinct strategies are used for activation in the early Drosophila embryo and this may reflect general dynamic properties of promoters used throughout development. ChIP-seq for Pol II, TBP, H3K4me3, H3K27me3 and H3Ac in Drosophila embryos
2013-07-26 | E-GEOD-41700 | biostudies-arrayexpress
Project description:NR5A2 bridges zygotic genome activation to lineage segregation in early mouse development
| PRJNA903396 | ENA
Project description:Early embryogenesis is characterized by the maternal to zygotic transition (MTZ), in which maternally deposited messenger RNAs are translated and subsequently degraded while zygotic transcription begins. Posttranscriptional gene regulation by RNA-binding proteins (RBPs) is a dominant force controlling pre-zygotic gene expression. Here we describe the first in vivo mRNA-bound proteome in early Drosophila melanogaster embryos. mRNA interactome capture using conventional (254nm) and photoactivatable ribonucleoside-enhanced UV-crosslinking (365nm) was applied to detect RBPs bound to maternal and early zygotic polydenylated transcripts within the first two hours of embryogenesis. We identified a high confidence set of 476 putative RBPs and confirmed RNA-binding activity for most of the tested candidates. The majority of the identified proteins in the early fly mRNA interactome were known RBPs, harboring canonical RBPs features. Nearly hundred of the identified proteins were previously not known to bind RNA. Interestingly, mRNAs encoding RBPs and TFs exhibit time specific expression modules, in which RBPs dominate the first hours of embryonic development. Using fly-FISH data, we could show enriched RBP localization in the posterior embryo during these first hours of fly embryogenesis, suggesting general importance germ cell maturation.
2016-04-26 | PXD002992 | Pride
Project description:The cell cycle is ordered by a controlled network of kinases and phosphatases. To generate gametes via meiosis, two distinct and sequential chromosome segregation events occur without an intervening S phase. How canonical cell cycle controls are modified for meiosis is not well understood. Here, using highly synchronous budding yeast populations, we reveal how the global proteome and phosphoproteome change during the meiotic divisions. While protein abundance changes are limited to key cell cycle regulators, dynamic phosphorylation changes are pervasive. Our data indicate that two waves of cyclin-dependent kinase and Polo (Cdc5Polo) kinase activity drive successive meiotic divisions. These two distinct phases of phosphorylation are ensured by the meiosis-specific Spo13 protein, which rewires the phosphoproteome. Spo13 binds to Cdc5Polo to promote phosphorylation in meiosis I, particularly of substrates containing a variant of the canonical Cdc5Polo motif. Overall, our findings reveal that a master regulator of meiosis directs the activity of a kinase to change the phosphorylation landscape and elicit a developmental cascade.
2024-03-21 | PXD048618 | Pride