Expression of eukaryotic elongation initiation factor 1A differentially marks zygotic genome activation in biparental and parthenogenetic porcine embryos and correlates with in vitro developmental potential

2008 ◽  
Vol 20 (7) ◽  
pp. 818 ◽  
Author(s):  
Luca Magnani ◽  
Christine M. Johnson ◽  
Ryan A. Cabot
Keyword(s):  
Expression Profile ◽  
Initiation Factor ◽  
In Vitro Fertilisation ◽  
Zygotic Genome Activation ◽  
Cell Stage ◽  
Developmental Potential ◽  
Genome Activation ◽  
Parthenogenetic Embryos ◽  
Zygotic Genome

Zygotic genome activation (ZGA) is a major event during cleavage development. In vitro manipulation of mammalian embryos (including embryo culture) can result in developmental arrest around the time of ZGA. Eukaryotic elongation initiation factor 1A (eIF1A) has been used as a marker for ZGA in some mammalian species. We hypothesised expression of eIF1A can be used to assess ZGA in the pig; we also hypothesised that the expression profile of eIF1A can be used to assess developmental potential in vitro. The aims of the present study were to determine the expression pattern of eIF1A during porcine cleavage development and to assess its expression levels in embryos of different quality. We used a real-time reverse transcription–polymerase chain reaction assay to quantify eIF1A transcripts at different time points during cleavage development in porcine embryos produced by parthenogenetic activation (PA) and in vitro fertilisation (IVF). We found that eIF1A is activated at the two-cell stage in IVF embryos and at the four-cell stage in PA embryos. We showed that the increase in transcript levels observed in parthenogenetic embryos is dependent on de novo transcription. We found altered levels of eIF1A transcripts in parthenogenetic embryos that presented as either two- or eight-cell embryos 48 h after activation compared with four-cell embryos at the same time point. Our work supports the hypothesis that eIF1A is a marker of porcine ZGA and its expression profile can be used to assess embryo quality.

Expression of the HSP 70.1 gene, a landmark of early zygotic activity in the mouse embryo, is restricted to the first burst of transcription

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 113-122 ◽  
Author(s):  
E. Christians ◽  
E. Campion ◽  
E.M. Thompson ◽  
J.P. Renard
Keyword(s):  
Dna Replication ◽  
Mouse Embryo ◽  
Culture Conditions ◽  
Hsp 70 ◽  
Cell Stage ◽  
Embryonic Genome ◽  
Genome Activation ◽  
Alpha Amanitin ◽  
Zygotic Genome

Activation of the mouse embryonic genome at the 2-cell stage is characterized by the synthesis of several alpha-amanitin-sensitive polypeptides, some of which belong to the multigenic hsp 70 family. In the present work we show that a member of this family, the HSP 70.1 gene, is highly transcribed at the onset of zygotic genome activation. Transcription of this gene began as early as the 1-cell stage. Expression of the gene continued through the early 2-cell stage but was repressed before the completion of the second round of DNA replication. During this period we observed that the level of transcription was modulated by in vitro culture conditions. The coincidence of repression of HSP70.1 transcription with the second round of DNA replication was not found for other transcription-dependent polypeptides synthesized at the 2-cell stage.

scholarly journals Maternal Dppa2 and Dppa4 are dispensable for zygotic genome activation but important for offspring survival

Development ◽  
2021 ◽  
Vol 148 (24) ◽  
Author(s):  
Oana Kubinyecz ◽  
Fatima Santos ◽  
Deborah Drage ◽  
Wolf Reik ◽  
Melanie A. Eckersley-Maslin
Keyword(s):  
Null Allele ◽  
Embryonic Stem ◽  
Offspring Survival ◽  
Zygotic Genome Activation ◽  
Molecular Events ◽  
Genome Activation ◽  
Mitotic Chromatin ◽  
Zygotic Genome

ABSTRACT Zygotic genome activation (ZGA) represents the initiation of transcription following fertilisation. Despite its importance, we know little of the molecular events that initiate mammalian ZGA in vivo. Recent in vitro studies in mouse embryonic stem cells have revealed developmental pluripotency associated 2 and 4 (Dppa2/4) as key regulators of ZGA-associated transcription. However, their roles in initiating ZGA in vivo remain unexplored. We reveal that Dppa2/4 proteins are present in the nucleus at all stages of preimplantation development and associate with mitotic chromatin. We generated conditional single and double maternal knockout mouse models to deplete maternal stores of Dppa2/4. Importantly, Dppa2/4 maternal knockout mice were fertile when mated with wild-type males. Immunofluorescence and transcriptome analyses of two-cell embryos revealed that, although ZGA took place, there were subtle defects in embryos that lacked maternal Dppa2/4. Strikingly, heterozygous offspring that inherited the null allele maternally had higher preweaning lethality than those that inherited the null allele paternally. Together, our results show that although Dppa2/4 are dispensable for ZGA transcription, maternal stores have an important role in offspring survival, potentially via epigenetic priming of developmental genes.

scholarly journals Reciprocal zebrafish-medaka hybrids reveal maternal control of zygotic genome activation timing

2021 ◽  
Author(s):  
Krista R Gert ◽  
Luis Enrique Cabrera Quio ◽  
Maria Novatchkova ◽  
Yixuan Guo ◽  
Bradley R Cairns ◽  
...  
Keyword(s):  
Early Development ◽  
Hybrid System ◽  
Control Mechanisms ◽  
Zygotic Genome Activation ◽  
Zygotic Transcription ◽  
Versatile Tool ◽  
Paternal Control ◽  
Genome Activation ◽  
Zygotic Genome

After fertilization, the sperm and egg contribute unequally to the newly formed zygote. While the sperm contributes mainly paternal DNA, the egg provides both maternal DNA and the bulk of the future embryonic cytoplasm. Most embryonic processes (like the onset of zygotic transcription) depend on maternally-provided cytoplasmic components, and it is largely unclear whether paternal components besides the centrosome play a role in the regulation of early embryogenesis. Here we report a reciprocal zebrafish-medaka hybrid system as a powerful tool to investigate paternal vs. maternal influence during early development. By combining expression of zebrafish Bouncer on the medaka egg with artificial egg activation, we demonstrate the in vitro generation of paternal zebrafish x maternal medaka (reripes) hybrids. These hybrids complement the previously established paternal medaka x maternal zebrafish (latio) hybrids (Herberg et al., 2018). As proof of concept, we investigated maternal vs. paternal control of zygotic genome activation (ZGA) timing using this reciprocal hybrid system. RNA-seq analysis of the purebred fish species and hybrids revealed that the onset of ZGA is primarily governed by the egg. Overall, our study establishes the reciprocal zebrafish-medaka hybrid system as a versatile tool to dissect parental control mechanisms during early development.

scholarly journals Characterization of zygotic genome activation-dependent maternal mRNA clearance in mouse

2019 ◽  
Vol 48 (2) ◽  
pp. 879-894 ◽  
Author(s):  
Qian-Qian Sha ◽  
Ye-Zhang Zhu ◽  
Sen Li ◽  
Yu Jiang ◽  
Lu Chen ◽  
...  
Keyword(s):  
De Novo ◽  
Mouse Embryos ◽  
Developmental Competence ◽  
Preimplantation Embryos ◽  
Zygotic Genome Activation ◽  
Cell Stage ◽  
Maternal Mrna ◽  
Maternal Transcripts ◽  
Genome Activation ◽  
Zygotic Genome

Abstract An important event of the maternal-to-zygotic transition (MZT) in animal embryos is the elimination of a subset of the maternal transcripts that accumulated during oogenesis. In both invertebrates and vertebrates, a maternally encoded mRNA decay pathway (M-decay) acts before zygotic genome activation (ZGA) while a second pathway, which requires zygotic transcription, subsequently clears additional mRNAs (Z-decay). To date the mechanisms that activate the Z-decay pathway in mammalian early embryos have not been investigated. Here, we identify murine maternal transcripts that are degraded after ZGA and show that inhibition of de novo transcription stabilizes these mRNAs in mouse embryos. We show that YAP1-TEAD4 transcription factor-mediated transcription is essential for Z-decay in mouse embryos and that TEAD4-triggered zygotic expression of terminal uridylyltransferases TUT4 and TUT7 and mRNA 3′-oligouridylation direct Z-decay. Components of the M-decay pathway, including BTG4 and the CCR4-NOT deadenylase, continue to function in Z-decay but require reinforcement from the zygotic factors for timely removal of maternal mRNAs. A long 3′-UTR and active translation confer resistance of Z-decay transcripts to M-decay during oocyte meiotic maturation. The Z-decay pathway is required for mouse embryo development beyond the four-cell stage and contributes to the developmental competence of preimplantation embryos.

scholarly journals Arginine Regulates Zygotic Genome Activation in Porcine Embryos through Promoting Polyamine Synthesis☆

2021 ◽  
Author(s):  
Tianrui Zhang ◽  
Yingying Zheng ◽  
Tianya Kuang ◽  
Lianyu Yang ◽  
Hailong Jiang ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Lipid Droplet ◽  
Immunofluorescent Staining ◽  
Block Group ◽  
Arginine Metabolism ◽  
Zygotic Genome Activation ◽  
Cell Stage ◽  
Polyamine Synthesis ◽  
Genome Activation ◽  
Zygotic Genome

Abstract Background:Arginine has a positive effect on preimplantation development in pigs. However, the exact mechanism by which arginine promotes embryonic development to the blastocyst stage is not undefined. Here, single-cell RNA-sequencing technology was applied to porcine in vivo pre-implantation embryos from zygote to morula to determine transcription patterns of arginine metabolism-related genes during preimplantation embryonic development.Results:Transcriptome sequencing showed that arginine metabolism-related genes clearly changed from the 2-cell stage to the 4-cell stage, where zygotic genome activation (ZGA) occurred in porcine embryos. Further analysis of the correlation between arginine metabolism and ZGA shows that arginine metabolism-related genes are significantly correlated with key ZGA genes such as ZSCAN4, DPPA2 and EIF1A, indicating that arginine metabolism may be an indicator of porcine ZGA. To explore the correlation between arginine metabolism and ZGA, embryos cultured in the medium that removes all the amino acids, proteins and pyruvate in the PZM3 medium were employed to generate the ZGA blocked embryo model. The 4-cell arrest rate significantly increased at 72 h after activation, indicating impeded embryonic development. Meanwhile, results of immunofluorescent staining showed that the expression of SIRT1 protein during ZGA was significantly inhibited. Results of quantitative PCR showed that the expression of zygotic genes (ZSCAN4, DPPA2 and EIF1A) was significantly decreased. The above results indicate that the ZGA blocked embryo model was successfully established. Adding of arginine recovered embryonic development, SIRT1 and zygotic genes expression levels and initiated the ZGA. In addition, ROS content significantly increased when ZGA was blocked, and the GSH, ATP and lipid droplet content significantly decreased. After the addition of arginine in the block group, the ROS content significantly decreased, and the GSH, ATP and lipid droplet content significantly increased. Moreover, the ornithine decarboxylase (ODC) inhibitor difluoromethylornithine (DFMO) and arginine were added to the block group at the same time, and the effect of arginine was found to be inhibited. Conclusions: Arginine is essential for ZGA in porcine embryos. Arginine contributes to porcine ZGA by promoting polyamine synthesis in porcine embryos.

Comparison of glucose metabolism in in vivo- and in vitro-matured tammar wallaby oocytes and its relationship to developmental potential following intracytoplasmic sperm injection

2004 ◽  
Vol 16 (6) ◽  
pp. 617 ◽  
Author(s):  
Genevieve M. Magarey ◽  
Karen E. Mate
Keyword(s):  
Glucose Metabolism ◽  
Intracytoplasmic Sperm Injection ◽  
Tammar Wallaby ◽  
Blastocyst Stage ◽  
In Vitro Fertilisation ◽  
Cell Stage ◽  
Developmental Potential ◽  
Developmental Capacity

Although marsupial oocytes undergo nuclear maturation in vitro, there is, at present, no indication of their developmental potential, largely owing to the lack of in vitro fertilisation and related technologies for marsupials. Glucose metabolism has proven a useful indicator of oocyte cytoplasmic maturation and developmental potential in several eutherian species. Therefore, the aims of the present study were to compare: (1) the rates of glycolysis and glucose oxidation in immature, in vitro-matured and in vivo-matured tammar wallaby oocytes; and (2) the metabolic rate of individual oocytes with their ability to form pronuclei after intracytoplasmic sperm injection. The rates of glycolysis measured in immature (2.18 pmol oocyte–1 h–1), in vitro-matured (0.93 pmol oocyte–1 h–1) and in vivo-matured tammar wallaby oocytes (0.54 pmol oocyte–1 h–1) were within a similar range to values obtained in eutherian species. However, unlike the trend observed in eutherian oocytes, the glycolytic rate was significantly higher in immature oocytes compared with either in vivo- or in vitro-matured oocytes (P < 0.001) and significantly higher in in vitro-matured oocytes compared with in vivo-matured oocytes (P < 0.001). No relationship was identified between glucose metabolism and the developmental capacity of oocytes after intracytoplasmic sperm injection when assessed after 17–19 h. Oocytes that became fertilised (two pronuclei) or activated (one or more pronucleus) were not distinguished from others by their metabolic rates. Longer culture after intracytoplasmic sperm injection (e.g. blastocyst stage) may show oocyte glucose metabolism to be predictive of developmental potential; however, culture to the single-cell stage did not reveal any significant differences in normally developing embryos.

scholarly journals Transposable Element Dynamics and Regulation during Zygotic Genome Activation in Mammalian Embryos and Embryonic Stem Cell Model Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yixuan Low ◽  
Dennis Eng Kiat Tan ◽  
Zhenhua Hu ◽  
Shawn Ying Xuan Tan ◽  
Wee-Wei Tee
Keyword(s):  
Cell Model ◽  
Embryonic Stem ◽  
Model Systems ◽  
Specific Class ◽  
Mammalian Development ◽  
Zygotic Genome Activation ◽  
Somatic Tissues ◽  
Genome Activation ◽  
Zygotic Genome

Transposable elements (TEs) are mobile genetic sequences capable of duplicating and reintegrating at new regions within the genome. A growing body of evidence has demonstrated that these elements play important roles in host genome evolution, despite being traditionally viewed as parasitic elements. To prevent ectopic activation of TE transposition and transcription, they are epigenetically silenced in most somatic tissues. Intriguingly, a specific class of TEs—retrotransposons—is transiently expressed at discrete phases during mammalian development and has been linked to the establishment of totipotency during zygotic genome activation (ZGA). While mechanisms controlling TE regulation in somatic tissues have been extensively studied, the significance underlying the unique transcriptional reactivation of retrotransposons during ZGA is only beginning to be uncovered. In this review, we summarize the expression dynamics of key retrotransposons during ZGA, focusing on findings from in vivo totipotent embryos and in vitro totipotent-like embryonic stem cells (ESCs). We then dissect the functions of retrotransposons and discuss how their transcriptional activities are finetuned during early stages of mammalian development.

scholarly journals Pou5f3, SoxB1 and Nanog remodel chromatin on High Nucleosome Affinity Regions at Zygotic Genome Activation

2018 ◽  
Author(s):  
Marina Veil ◽  
Lev Yampolsky ◽  
Björn Grüning ◽  
Daria Onichtchouk
Keyword(s):  
Nucleosome Occupancy ◽  
Open Chromatin ◽  
Zygotic Genome Activation ◽  
Chromatin Dynamics ◽  
Cell Cycles ◽  
Dna Shape ◽  
Genome Activation ◽  
Zygotic Genome

AbstractThe zebrafish embryo is mostly transcriptionally quiescent during the first 10 cell cycles, until the main wave of Zygotic Genome Activation (ZGA) occurs, accompanied by fast chromatin remodeling. At ZGA, homologs of mammalian stem cell transcription factors (TFs) Pou5f3, Nanog and Sox19b bind to thousands of developmental enhancers to initiate transcription. So far, how these TFs influence chromatin dynamics at ZGA has remained unresolved. To address this question, we analyzed nucleosome positions in wild-type and Maternal-Zygotic (MZ) mutants for pou5f3 and nanog by MNase-seq. We show that Nanog, Sox19b and Pou5f3 bind to the High Nucleosome Affinity Regions (HNARs). HNARs are spanning over 600 bp, featuring high in vivo and predicted in vitro nucleosome occupancy and high predicted propeller twist DNA shape value. We suggest a two-step nucleosome destabilization-depletion model, where the same intrinsic DNA properties of HNAR promote both high nucleosome occupancy and differential binding of TFs. In the first step, already prior to ZGA, Pou5f3 and Nanog destabilize nucleosomes on HNAR centers genome-wide. In the second step, post-ZGA, Nanog, Pou5f3 and SoxB1 maintain open chromatin state on the subset of HNARs, acting synergistically. Nanog binds to the HNAR center, while the Pou5f3 stabilizes the flanks. The HNAR model will provide a useful tool for genome regulatory studies in the variety of biological systems.

scholarly journals DPPA2 and DPPA4 are necessary to establish a totipotent state in mouse embryonic stem cells

2018 ◽  
Author(s):  
Alberto De Iaco ◽  
Alexandre Coudray ◽  
Julien Duc ◽  
Didier Trono
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Chromatin Accessibility ◽  
Early Embryo ◽  
Zygotic Genome Activation ◽  
Cell Stage ◽  
Oocyte Expression ◽  
Genome Activation ◽  
Zygotic Genome

AbstractAfter fertilization of the transcriptionally silent oocyte, expression from both parental chromosomes is launched through so-called zygotic genome activation (ZGA), occurring in the mouse at the 2-cell stage. Amongst the first elements to be transcribed are the Dux gene, the product of which secondarily induces a wide array of ZGA genes, and a subset of evolutionary recent LINE-1 retrotransposons, which regulate chromatin accessibility in the early embryo. The maternally-inherited factors that activate Dux and LINE-1 transcription have so far remained unknown. Here we identify the paralog proteins DPPA2 and DPPA4 as responsible for this process.

scholarly journals DPPA2 and DPPA4 are dispensable for mouse zygotic genome activation and preimplantation development

Development ◽  
2021 ◽  
Author(s):  
Zhiyuan Chen ◽  
Zhenfei Xie ◽  
Yi Zhang
Keyword(s):  
De Novo ◽  
Genetic Manipulation ◽  
Embryonic Stem ◽  
Preimplantation Development ◽  
Dependent Manner ◽  
Maternal Factors ◽  
Zygotic Genome Activation ◽  
Genome Activation ◽  
Zygotic Genome

How maternal factors in oocytes initiate zygotic genome activation (ZGA) remains elusive in mammals, partly due to the challenge of de novo identification of key factors using scarce materials. The 2-cell (2C) embryo like cells has been widely used as an in vitro model to understand mouse ZGA and totipotency given its expression of a group of 2C embryo-specific genes and its simplicity for genetic manipulation. Recent studies indicate that DPPA2 and DPPA4 are required for establishing the 2C-like state in mouse embryonic stem cells (ESCs) in a DUX-dependent manner. These results suggest that DPPA2 and DPPA4 are essential maternal factors that regulate Dux and ZGA in embryos. By analyzing maternal knockout and maternal-zygotic knockout embryos, we unexpectedly found that DPPA2 and DPPA4 are dispensable for Dux activation, ZGA, and preimplantation development. Our study suggests that 2C-like cells do not fully recapitulate 2-cell embryos in terms of 2C-gene regulation and cautions should be taken when studying ZGA and totipotency using 2C-like cells as the model system.

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