scholarly journals Expression and Potential Role of microRNA-29b in Mouse Early Embryo Development

2015 ◽  
Vol 35 (3) ◽  
pp. 1178-1187 ◽  
Author(s):  
Junqiang Zhang ◽  
Ying Wang ◽  
Xiaoguang Liu ◽  
Shenglin Jiang ◽  
Chun Zhao ◽  
...  

Background/Aims: MicroRNA-29b (miR29b) has been previously identified in early mouse embryos through miRNA microarray analysis. Recent research has indicated that miR29b participates in DNA methylation by regulating DNA methyltransferase 3a/3b (Dnmt3a/3b) expression. However, the expression pattern and biological function of miR29b in mouse preimplantation embryonic development remain unknown. Methods: In this study, we examined the expression patterns of miR29b and Dnmt3a/3b in mouse early embryos at different developmental stages. Subsequently, expression and localization of DNMT3A/3B protein was analyzed in mouse early embryos by immunofluorescence staining. The biological function of miR29b in mouse early embryos was analyzed by microinjection of commercially available miRNA-specific inhibitors and mimics. Results: Our data showed that Dnmt3a/3b mRNA expression is negatively regulated by miR29b in mouse early embryos. Immunofluorescence analysis revealed that DNMT3A/3B protein expression is predominantly localized within the nucleoplasm of embryos. Alterations to the activity of miR29b could change the DNA methylation levels in mouse preimplantation embryos and lead to a developmental blockade, from the morula to the blastocyst stage. Conclusion: These results indicated a role for the miR29b-Dnmt3a/3b-DNA methylation axis in mouse early embryonic development, and we provide evidence that miR29b is indispensable for mouse early embryonic development. This study contributes to a preliminary understanding of the role of miR29b during mouse embryonic development.

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Sangeetha Mahadevan ◽  
Varsha Sathappan ◽  
Budi Utama ◽  
Isabel Lorenzo ◽  
Khalied Kaskar ◽  
...  

Abstract Mammalian parental genomes contribute differently to early embryonic development. Before activation of the zygotic genome, the maternal genome provides all transcripts and proteins required for the transition from a highly specialized oocyte to a pluripotent embryo. Depletion of these maternally-encoded transcripts frequently results in failure of preimplantation embryonic development, but their functions in this process are incompletely understood. We found that female mice lacking NLRP2 are subfertile because of early embryonic loss and the production of fewer offspring that have a wide array of developmental phenotypes and abnormal DNA methylation at imprinted loci. By demonstrating that NLRP2 is a member of the subcortical maternal complex (SCMC), an essential cytoplasmic complex in oocytes and preimplantation embryos with poorly understood function, we identified imprinted postzygotic DNA methylation maintenance, likely by directing subcellular localization of proteins involved in this process, such as DNMT1, as a new crucial role of the SCMC for mammalian reproduction.


Author(s):  
Shuang Li ◽  
Yan Shi ◽  
Yanna Dang ◽  
Lei Luo ◽  
Bingjie Hu ◽  
...  

Abstract The NOTCH signaling pathway plays an important role in regulating various biological processes, including lineage specification and apoptosis. Multiple components of the NOTCH pathway have been identified in mammalian preimplantation embryos. However, the precise role of the NOTCH pathway in early embryonic development is poorly understood, especially in large animals. Here, we show that the expression of genes encoding key transcripts of the NOTCH pathway is dynamic throughout early embryonic development. We also confirm the presence of active NOTCH1 and RBPJ. By using pharmacological and RNAi tools, we demonstrate that the NOTCH pathway is required for the proper development of bovine early embryos. This functional consequence could be partly attributed to the major transcriptional mediator-RBPJ, whose deficiency also compromised the embryo quality. Indeed, both NOTCH1 and RBPJ knockdown cause a significant increase of histone H3 serine 10 phosphorylation (pH3S10, a mitosis marker) positive blastomeres, suggesting a cell cycle arrest at mitosis. Importantly, RNA-seq analyses reveal that either NOTCH1 or RBPJ depletion triggers a reduction in H1FOO that encodes the oocyte-specific linker histone H1 variant. Interestingly, depleting H1FOO results in detrimental effects on the developmental competence of early embryos, similar with NOTCH1 inhibition. Overall, our results reveal a crucial role for NOTCH pathway in regulating bovine preimplantation development, likely by controlling cell proliferation and maintaining H1FOO expression.


Zygote ◽  
2021 ◽  
pp. 1-8
Author(s):  
Daohong He ◽  
Guobo Han ◽  
Xiaomeng Zhang ◽  
Jingyu Sun ◽  
Yongnan Xu ◽  
...  

Summary Methomyl is a widely used carbamate insecticide and environmental oestrogen that has adverse effects on the reproductive system. However, there have been no reports on the effect of methomyl on early embryos in mammals. In this study, we explored the effect of methomyl exposure on the quality of early embryonic development in mice and the possible mechanisms. During in vitro culture, different concentrations of methomyl (10, 20, 30 and 35 μM) were added to mouse zygote medium. The results showed that methomyl had an adverse effect on early embryonic development. Compared with the control group, the addition of 30 μM methomyl significantly reduced the rate of early embryo blastocyst formation. Methomyl exposure can increase oxidative stress and impair mitochondrial function, which may be the cause of blastocyst formation. In addition, we found that methomyl exposure promoted apoptosis and autophagy in mouse blastocysts. The toxic effect of methomyl on early embryos may be the result of oxidative stress induction. Taken together, our results indicate that methomyl can cause embryonic development defects in mice, thereby reducing the quality of early embryo development.


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Jingwen Wang ◽  
Junjiu Huang ◽  
Guang Shi

AbstractTransposable elements constitute about half of the mammalian genome, and can be divided into two classes: the class I (retrotransposons) and the class II (DNA transposons). A few hundred types of retrotransposons, which are dynamic and stage specific, have been annotated. The copy numbers and genomic locations are significantly varied in species. Retrotransposons are active in germ cells, early embryos and pluripotent stem cells (PSCs) correlated with low levels of DNA methylation in epigenetic regulation. Some key pluripotency transcriptional factors (such as OCT4, SOX2, and NANOG) bind retrotransposons and regulate their activities in PSCs, suggesting a vital role of retrotransposons in pluripotency maintenance and self-renewal. In response to retrotransposons transposition, cells employ a number of silencing mechanisms, such as DNA methylation and histone modification. This review summarizes expression patterns, functions, and regulation of retrotransposons in PSCs and early embryonic development.


2021 ◽  
Vol 33 (2) ◽  
pp. 139
Author(s):  
L. Luo ◽  
Y. Dang ◽  
Y. Shi ◽  
P. Zhao ◽  
Y. Zhang ◽  
...  

SIN3 transcription regulator family member A (SIN3A) is the central scaffold protein of the SIN3/HDAC (histone deacetylase) transcriptional repressor complex. We previously found that SIN3A participates in the mouse pre-implantation development by finetuning HDAC1 expression. However, it remains unresolved whether this functional significance of SIN3A is conserved in other mammals. The objective of this work was thus to characterise the expression profiles and the functional role of SIN3A in pre-implantation development using non-rodent animal models. RNA sequencing results show that a large amount of SIN3A mRNA is present in oocytes and early embryos before embryonic genome activation and a low amount thereafter, suggesting a maternal origin of SIN3A in all species examined. Interestingly, immunofluorescence data show that SIN3A protein level peaks at the 4-cell stage in pigs compared with the morula stage in cattle, suggesting a differential role of SIN3A among species. To explore the function of SIN3A in early embryonic development, we used a short interfering (si)RNA-mediated knockdown approach in porcine parthenogenetic activated (PA) embryos. Immunocytochemical analysis showed that SIN3A levels were diminished ∼80% compared with nonspecific siRNA (NC) injected control (n=3). To monitor the developmental potential of embryo depleted of SIN3A, we injected SIN3A-siRNA into MII stage oocytes, followed by parthenogenetic activation, and percent cleavage and blastocyst formation were recorded. We found that SIN3A knockdown (KD) did not affect the cleavage rate (NC vs. KD, 83.63±3.63% vs. 80.08±4.66%, n=5), but significantly reduced blastocyst rate compared with the NC group (NC vs. KD, 36.64±4.28% vs. 6.33±3.12%, n=5). Specifically, SIN3A depletion in early embryos causes developmental arrest at 2-cell stage in pigs but does not affect early embryonic development in bovines. In contrast with mouse data, SIN3A depletion results in only a slight decrease and even no difference in HDAC1 expression in porcine and bovine early embryos, respectively. In addition, HDAC1 knockdown does not cause 2-cell block but leads to a reduced blastocyst rate, suggesting that the effect of SIN3A depletion on porcine early embryos is independent of HDAC1. RNA-Seq analysis was used to compare the global transcript content between NC and KD 2-cell embryos. A total of 23 genes (14 upregulated and 9 downregulated) had undergone significant changes. Interestingly, cyclin B1 (CCNB1) ranked second among downregulated genes. To test whether knockdown of CCNB1 would display a similar phenotype in porcine early embryos, we injected CCNB1-siRNA into pronuclear stage. CCNB1 KD resulted in a similar phenotype as SIN3A depletion. Injection of exogenous CCNB1 mRNA into SIN3A-depleted embryos could partly rescue embryonic development. In conclusion, our results indicate SIN3A plays an essential role in porcine early embryonic development, probably involving the regulation of CCNB1 expression. This work was funded by National Natural Science Foundation of China, the Anhui Provincial Natural Science Foundation and China Postdoctoral Science Foundation.


2019 ◽  
Author(s):  
Tra Thi Huong Dinh ◽  
Hiroyoshi Iseki ◽  
Seiya Mizuno ◽  
Saori Iijima-Mizuno ◽  
Yoko Tanimoto ◽  
...  

ABSTRACTCDK5 and Abl enzyme substrate 2 (Cables2), a member of the Cables family that has a C-terminal cyclin box-like domain, is widely expressed in adult mouse tissues. However, the physiological role of Cables2 in vivo is unknown. We show here that Cables2-deficiency causes post-gastrulation embryonic lethality in mice. The mutant embryos progress to gastrulation, but then arrest, and fail to grow. Analysis of gene expression patterns reveals that formation of the anterior visceral endoderm and the primitive streak is impaired in Cables2-deficient embryos. Tetraploid complementation analyses support the critical requirement of Cables2 in both the epiblast and visceral endoderm for progression of embryogenesis. In addition, we show that Cables2 physically interacts with a key mediator of the canonical Nodal pathway, Smad2, and augments its transcriptional activity. These findings provide novel insights into the essential role of Cables2 in the early embryonic development in mice.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Krystyna Ślaska-Kiss ◽  
Nikolett Zsibrita ◽  
Mihály Koncz ◽  
Pál Albert ◽  
Ákos Csábrádi ◽  
...  

AbstractTargeted DNA methylation is a technique that aims to methylate cytosines in selected genomic loci. In the most widely used approach a CG-specific DNA methyltransferase (MTase) is fused to a sequence specific DNA binding protein, which binds in the vicinity of the targeted CG site(s). Although the technique has high potential for studying the role of DNA methylation in higher eukaryotes, its usefulness is hampered by insufficient methylation specificity. One of the approaches proposed to suppress methylation at unwanted sites is to use MTase variants with reduced DNA binding affinity. In this work we investigated how methylation specificity of chimeric MTases containing variants of the CG-specific prokaryotic MTase M.SssI fused to zinc finger or dCas9 targeting domains is influenced by mutations affecting catalytic activity and/or DNA binding affinity of the MTase domain. Specificity of targeted DNA methylation was assayed in E. coli harboring a plasmid with the target site. Digestions of the isolated plasmids with methylation sensitive restriction enzymes revealed that specificity of targeted DNA methylation was dependent on the activity but not on the DNA binding affinity of the MTase. These results have implications for the design of strategies of targeted DNA methylation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aslı Okan ◽  
Necdet Demir ◽  
Berna Sozen

AbstractDiabetes mellitus (DM) has profound effects on the female mammalian reproductive system, and early embryonic development, reducing female reproductive outcomes and inducing developmental programming in utero. However, the underlying cellular and molecular mechanisms remain poorly defined. Accumulating evidence implicates endoplasmic reticulum (ER)-stress with maternal DM associated pathophysiology. Yet the direct pathologies and causal events leading to ovarian dysfunction and altered early embryonic development have not been determined. Here, using an in vivo mouse model of Type 1 DM and in vitro hyperglycaemia-exposure, we demonstrate the activation of ER-stress within adult ovarian tissue and pre-implantation embryos. In diabetic ovaries, we show that the unfolded protein response (UPR) triggers an apoptotic cascade by the co-activation of Caspase 12 and Cleaved Caspase 3 transducers. Whereas DM-exposed early embryos display differential ER-associated responses; by activating Chop in within embryonic precursors and Caspase 12 within placental precursors. Our results offer new insights for understanding the pathological effects of DM on mammalian ovarian function and early embryo development, providing new evidence of its mechanistic link with ER-stress in mice.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhi-Qiang Du ◽  
Hao Liang ◽  
Xiao-Man Liu ◽  
Yun-Hua Liu ◽  
Chonglong Wang ◽  
...  

AbstractSuccessful early embryo development requires the correct reprogramming and configuration of gene networks by the timely and faithful execution of zygotic genome activation (ZGA). However, the regulatory principle of molecular elements and circuits fundamental to embryo development remains largely obscure. Here, we profiled the transcriptomes of single zygotes and blastomeres, obtained from in vitro fertilized (IVF) or parthenogenetically activated (PA) porcine early embryos (1- to 8-cell), focusing on the gene expression dynamics and regulatory networks associated with maternal-to-zygote transition (MZT) (mainly maternal RNA clearance and ZGA). We found that minor and major ZGAs occur at 1-cell and 4-cell stages for both IVF and PA embryos, respectively. Maternal RNAs gradually decay from 1- to 8-cell embryos. Top abundantly expressed genes (CDV3, PCNA, CDR1, YWHAE, DNMT1, IGF2BP3, ARMC1, BTG4, UHRF2 and gametocyte-specific factor 1-like) in both IVF and PA early embryos identified are of vital roles for embryo development. Differentially expressed genes within IVF groups are different from that within PA groups, indicating bi-parental and maternal-only embryos have specific sets of mRNAs distinctly decayed and activated. Pathways enriched from DEGs showed that RNA associated pathways (RNA binding, processing, transport and degradation) could be important. Moreover, mitochondrial RNAs are found to be actively transcribed, showing dynamic expression patterns, and for DNA/H3K4 methylation and transcription factors as well. Taken together, our findings provide an important resource to investigate further the epigenetic and genome regulation of MZT events in early embryos of pigs.


2020 ◽  
Author(s):  
Jing Wei ◽  
Jia Cheng ◽  
Nicholas J Waddell ◽  
Zi-Jun Wang ◽  
Xiaodong Pang ◽  
...  

Abstract Emerging evidence suggests that epigenetic mechanisms regulate aberrant gene transcription in stress-associated mental disorders. However, it remains to be elucidated about the role of DNA methylation and its catalyzing enzymes, DNA methyltransferases (DNMTs), in this process. Here, we found that male rats exposed to chronic (2-week) unpredictable stress exhibited a substantial reduction of Dnmt3a after stress cessation in the prefrontal cortex (PFC), a key target region of stress. Treatment of unstressed control rats with DNMT inhibitors recapitulated the effect of chronic unpredictable stress on decreased AMPAR expression and function in PFC. In contrast, overexpression of Dnmt3a in PFC of stressed animals prevented the loss of glutamatergic responses. Moreover, the stress-induced behavioral abnormalities, including the impaired recognition memory, heightened aggression, and hyperlocomotion, were partially attenuated by Dnmt3a expression in PFC of stressed animals. Finally, we found that there were genome-wide DNA methylation changes and transcriptome alterations in PFC of stressed rats, both of which were enriched at several neural pathways, including glutamatergic synapse and microtubule-associated protein kinase signaling. These results have therefore recognized the potential role of DNA epigenetic modification in stress-induced disturbance of synaptic functions and cognitive and emotional processes.


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