Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA232136 | ENA |
REPOSITORIES: ENA
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Project description:Many of the structural and mechanistic requirements of oocyte-mediated nuclear reprogramming remain elusive. Previous accounts that transcriptional reprogramming of somatic nuclei in mouse zygotes may be complete in 24-36 hours, far more rapidly than in other reprogramming systems, raise the question of whether the mere exposure to the activated mouse ooplasm is sufficient to enact reprogramming in a nucleus. We therefore prevented DNA replication and cytokinesis, which ensue after nuclear transfer, in order to assess their requirement for transcriptional reprogramming of the key pluripotency genes Oct4 (Pou5f1) and Nanog in cloned mouse embryos. Using transcriptome and allele-specific analysis, we observed that hundreds of mRNAs, but not Oct4 and Nanog, became elevated in nucleus-transplanted oocytes without DNA replication. Progression through the first round of DNA replication was essential but not sufficient for transcriptional reprogramming of Oct4 and Nanog, whereas cytokinesis and thereby cell-cell interactions were dispensable for transcriptional reprogramming. Responses similar to clones also were observed in embryos produced by fertilization in vitro. Our results link the occurrence of reprogramming to a previously unappreciated requirement of oocyte-mediated nuclear reprogramming, namely DNA replication. Nuclear transfer alone affords no immediate transition from a somatic to a pluripotent gene expression pattern unless DNA replication is also in place. This study is therefore a resource to appreciate that the quest for always faster reprogramming methods may collide with a limit that is dictated by the cell cycle.
2016-12-17 | GSE53497 | GEO
Project description:In several metazoans the number of active replication origins in embryonic nuclei is higher than in somatic ones, ensuring rapid genome duplication during synchronous embryonic cell divisions. High replication origin density can be restored by somatic nuclear reprogramming. However, mechanisms underlying high replication origin density formation coupled to rapid cell cycles are poorly understood. Here, we characterized a fraction of Xenopus egg extract able to stimulate somatic DNA replication.
2020-03-19 | PXD017383 | Pride
Project description:Transfer of somatic cell nuclei to enucleated eggs or ectopic expression of specific transcription factors are two different reprogramming strategies used to generate pluripotent cells from differentiated cells. However, they are poorly efficient and other unknown factors might be required to increase their success rate. Here, we show that Xenopus egg extracts at the metaphase stage (M phase) have a strong reprogramming activity on mouse embryonic fibroblasts (MEFs). First, they reset replication properties of MEF nuclei toward a replication profile characteristic of early development and they erase several epigenetic marks, such as trimethylation of H3K9, H3K4 and H4K20. Second, when MEFs are reversibly permeabilized in the presence of M phase Xenopus egg extracts, they show a transient increase in cell proliferation, form colonies and start to express specific pluripotency markers. Finally, transient exposure of MEF nuclei to M phase Xenopus egg extracts increases the success of nuclear transfer to enucleated mouse oocytes and strongly synergize with the production of pluripotent stem cells by ectopic expression of transcription factors. The mitotic stage of the egg extract is crucial as neither of these effects is detected when using interphasic Xenopus egg extracts. Our data demonstrate that mitosis is essential to make mammalian somatic nuclei prone to reprogramming and that, surprisingly, the heterologous Xenopus system has features that are conserved enough to remodel mammalian nuclei. MEF cells were infected by retroviruses encoding for Oct4, Sox2, Klf4 and c-Myc and, then reversibly permeabilized and treated with Xenopus M-phase extract. All samples of each cell type (e.g. untreated MEF, ES cells and M-iPS cells) were made in triplicates. Total RNAs were extracted with RNeasy kit and hybridized on Nimblegen MM9 microarrays.
2011-11-21 | E-GEOD-31691 | biostudies-arrayexpress
Project description:Transfer of somatic cell nuclei to enucleated eggs or ectopic expression of specific transcription factors are two different reprogramming strategies used to generate pluripotent cells from differentiated cells. However, they are poorly efficient and other unknown factors might be required to increase their success rate. Here, we show that Xenopus egg extracts at the metaphase stage (M phase) have a strong reprogramming activity on mouse embryonic fibroblasts (MEFs). First, they reset replication properties of MEF nuclei toward a replication profile characteristic of early development and they erase several epigenetic marks, such as trimethylation of H3K9, H3K4 and H4K20. Second, when MEFs are reversibly permeabilized in the presence of M phase Xenopus egg extracts, they show a transient increase in cell proliferation, form colonies and start to express specific pluripotency markers. Finally, transient exposure of MEF nuclei to M phase Xenopus egg extracts increases the success of nuclear transfer to enucleated mouse oocytes and strongly synergize with the production of pluripotent stem cells by ectopic expression of transcription factors. The mitotic stage of the egg extract is crucial as neither of these effects is detected when using interphasic Xenopus egg extracts. Our data demonstrate that mitosis is essential to make mammalian somatic nuclei prone to reprogramming and that, surprisingly, the heterologous Xenopus system has features that are conserved enough to remodel mammalian nuclei.
2011-11-21 | GSE31691 | GEO
Project description:Active gene transcription is associated with an open chromatin configuration at gene regulatory regions. However, the relationship between chromatin architecture of somatic cells and transcriptional activation during nuclear reprogramming in oocytes is unclear. We therefore examined changes in open chromatin states before and after transplantation of mouse somatic nuclei into Xenopus laevis oocytes by using the Assay for Transposase-Accessible Chromatin Sequencing (ATAC-seq).
2018-07-10 | GSE98776 | GEO
Project description:Mammalian oocytes can reprogram somatic cells into totipotent state, which allows animal cloning through somatic cell nuclear transfer (SCNT). However, the great majority of SCNT embryos fail to develop to term due to poorly defined reprogramming defects. Here we demonstrate that histone H3 lysine 9 trimethylation (H3K9me3) in donor nuclei is a major epigenetic barrier that prevents efficient nuclear reprogramming in mouse oocytes. Comparative transcriptome analysis of early embryos revealed reprogramming resistant regions (RRRs) where transcriptional activation at 2-cell embryos is inhibited by SCNT compared to in vitro fertilization (IVF). RRRs significantly overlap with H3K9me3 enrichment in donor somatic cells. Importantly, removal of the H3K9me3 by ectopic expression of an H3K9me3 demethylase Kdm4d in recipient oocytes not only reactivates most RRRs, but also greatly improves development of SCNT embryos. Furthermore, the use of Suv39h1/2-depleted somatic nuclei as donors also greatly improves the development of SCNT embryos. Our study thus reveals H3K9me3 as an epigenetic barrier in SCNT-mediated reprogramming and provides a feasible method for improving mammalian cloning efficiency.
2014-11-07 | GSE59073 | GEO
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
2014-06-02 | E-GEOD-56762 | biostudies-arrayexpress
Project description:Mammalian oocytes have the ability to reset the transcriptional program of differentiated somatic cells into that of totipotent embryos through somatic cell nuclear transfer (SCNT). However, the mechanisms underlying SCNT-mediated reprogramming are largely unknown. To understand the mechanisms governing chromatin reprogramming during SCNT, we profiled DNaseI hypersensitive sites (DHSs) in donor cumulus cells and 1-cell stage SCNT embryos. To our surprise, the chromatin accessibility landscape of the donor cells is drastically changed to recapitulate that of the in vitro fertilization (IVF)-derived zygotes within 12 hours. Interestingly, this DHS reprogramming takes place even in the presence of a DNA replication inhibitor, suggesting that SCNT-mediated DHS reprogramming is independent of DNA replication. Thus, the study not only reveals the rapid and drastic nature of the changes in chromatin accessibility through SCNT, but also provides a DNA replication-independent model for studying cellular reprogramming.
2018-05-14 | GSE110851 | GEO
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.
2014-06-02 | GSE56762 | GEO
Project description:Somatic cells can be reprogrammed to a pluripotent state by nuclear transfer into oocytes, yet developmental arrest often occurs. While incomplete transcriptional reprogramming is known to cause developmental failure, reprogramming also involves concurrent changes in gene expression, cell cycle progression and nuclear structure. Here we study cellular reprogramming events in human and mouse nuclear transfer (NT) embryos prior to embryonic genome activation. We show that genetic instability marked by frequent chromosome segregation errors and DNA damage arise prior to, and independent of, transcriptional activity. These errors occur following transition through DNA replication and are repaired by BRCA1. In the absence of mitotic nuclear remodeling, DNA replication is delayed and errors are exacerbated in subsequent mitosis. These results demonstrate that independent of gene expression, cell type-specific features of cell cycle progression constitute a barrier sufficient to prevent the transition from one cell type to another during reprogramming.
2017-01-05 | GSE93123 | GEO