Sodium Fluoride Affects DNA Methylation of Imprinted Genes in Mouse Early Embryos

2015 ◽  
Vol 147 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Lei Zhao ◽  
Sheng Zhang ◽  
Xinglan An ◽  
Wentao Tan ◽  
Bo Tang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Embryonic Development ◽  
Mrna Level ◽  
Mouse Embryos ◽  
Imprinted Genes ◽  
Male Mice ◽  
Early Embryos ◽  
Pregnant Mice ◽  
H19 Gene ◽  
Early Mouse

Fluorine is reported to affect embryonic development, but the underlining mechanism is unclear. The modification of DNA methylation of the H19 and Peg3 genes is important in embryonic development. Therefore, the effect of fluorine on methylation of H19 and Peg3 during early mouse embryos was studied. It was shown that the H19 gene was significantly downmethylated in E2.5, E3.5, and E4.5 embryos from pregnant mice treated with 120 mg/l NaF in drinking water for 48 h. But methylation of both H19 and Peg3 genes was disrupted when the parent male mice were treated with NaF for 35 days. H19 DNA methylation decreased significantly, while Peg3 was almost completely methylated. However, when pregnant mice, mated with NaF-treated male mice, were again treated with NaF for 48 h, either H19 or Peg3 methylation in the embryos decreased significantly. In addition, the mRNA level of H19 considerably increased in E3.5 and E4.5 embryos from NaF-treated pregnant mice. Further, the expression of DNMT1 decreased significantly after NaF treatment. Conclusively, we demonstrated that fluorine may adversely affect early embryonic development by disrupting the methylation of H19 and Peg3 through downregulation of DNMT1.

scholarly journals Specific transgenerational imprinting effects of the endocrine disruptor methoxychlor on male gametes

Reproduction ◽  
2011 ◽  
Vol 141 (2) ◽  
pp. 207-216 ◽  
Author(s):  
Christelle Stouder ◽  
Ariane Paoloni-Giacobino
Keyword(s):  
Adult Male ◽  
Endocrine Disrupting Chemicals ◽  
Methylation Pattern ◽  
Imprinted Genes ◽  
Male Mice ◽  
Systematic Analysis ◽  
Adult Mice ◽  
Male Gametes ◽  
Pregnant Mice ◽  
Methylation Defects

Endocrine-disrupting chemicals (EDCs), among which methoxychlor (MXC), have been reported to affect the male reproductive system. This study evaluates the possible deleterious effects of MXC on imprinted genes. After administration of the chemical in adult male mice or in pregnant mice we analyzed by pyrosequencing possible methylation defects in two paternally imprinted (H19 and Meg3 (Gtl2)) and three maternally imprinted (Mest (Peg1), Snrpn, and Peg3) genes in the sperm and in the tail, liver, and skeletal muscle DNAs of the adult male mice and of the male offspring. MXC treatment of adult mice decreased the percentages of methylated CpGs of Meg3 and increased those of Mest, Snrpn, and Peg3 in the sperm DNA. MXC treatment of pregnant mice decreased the mean sperm concentrations by 30% and altered the methylation pattern of all the imprinted genes tested in the F1 offspring. In the latter case, MXC effects were transgenerational but disappeared gradually from F1 to F3. MXC did not affect imprinting in the somatic cells, suggesting that it exerts its damaging effects via the process of reprogramming that is unique to gamete development. A systematic analysis at the CpG level showed a heterogeneity in the CpG sensitivity to MXC. This observation suggests that not only DNA methylation but also other epigenetic modifications can explain the transgenerational effects of MXC. The reported effects of EDCs on human male spermatogenesis might be mediated by complex imprinting alterations analogous to those described in this study.

scholarly journals ZFP57 dictates allelic expression switch of target imprinted genes

2021 ◽  
Vol 118 (5) ◽  
pp. e2005377118
Author(s):  
Weijun Jiang ◽  
Jiajia Shi ◽  
Jingjie Zhao ◽  
Qiu Wang ◽  
Dan Cong ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Notch Signaling ◽  
Notch Pathway ◽  
Notch Signaling Pathway ◽  
Mouse Embryos ◽  
The Other ◽  
Allelic Expression ◽  
Monoallelic Expression ◽  
Imprinted Genes ◽  
Parent Of Origin

ZFP57 is a master regulator of genomic imprinting. It has both maternal and zygotic functions that are partially redundant in maintaining DNA methylation at some imprinting control regions (ICRs). In this study, we found that DNA methylation was lost at most known ICRs in Zfp57 mutant embryos. Furthermore, loss of ZFP57 caused loss of parent-of-origin–dependent monoallelic expression of the target imprinted genes. The allelic expression switch occurred in the ZFP57 target imprinted genes upon loss of differential DNA methylation at the ICRs in Zfp57 mutant embryos. Specifically, upon loss of ZFP57, the alleles of the imprinted genes located on the same chromosome with the originally methylated ICR switched their expression to mimic their counterparts on the other chromosome with unmethylated ICR. Consistent with our previous study, ZFP57 could regulate the NOTCH signaling pathway in mouse embryos by impacting allelic expression of a few regulators in the NOTCH pathway. In addition, the imprinted Dlk1 gene that has been implicated in the NOTCH pathway was significantly down-regulated in Zfp57 mutant embryos. Our allelic expression switch models apply to the examined target imprinted genes controlled by either maternally or paternally methylated ICRs. Our results support the view that ZFP57 controls imprinted expression of its target imprinted genes primarily through maintaining differential DNA methylation at the ICRs.

scholarly journals Dnmt1 binds and represses genomic retroelements via DNA methylation in mouse early embryos

2020 ◽  
Vol 48 (15) ◽  
pp. 8431-8444 ◽  
Author(s):  
Byungkuk Min ◽  
Jung Sun Park ◽  
Young Sun Jeong ◽  
Kyuheum Jeon ◽  
Yong-Kook Kang
Keyword(s):  
Dna Methylation ◽  
Cpg Islands ◽  
Endogenous Retrovirus ◽  
Dna Demethylation ◽  
Mouse Development ◽  
Genome Wide ◽  
Early Embryos ◽  
Dna Adenine Methylase ◽  
Early Mouse ◽  
Early Developmental

Abstract Genome-wide passive DNA demethylation in cleavage-stage mouse embryos is related to the cytoplasmic localization of the maintenance methyltransferase DNMT1. However, recent studies provided evidences of the nuclear localization of DNMT1 and its contribution to the maintenance of methylation levels of imprinted regions and other genomic loci in early embryos. Using the DNA adenine methylase identification method, we identified Dnmt1-binding regions in four- and eight-cell embryos. The unbiased distribution of Dnmt1 peaks in the genic regions (promoters and CpG islands) as well as the absence of a correlation between the Dnmt1 peaks and the expression levels of the peak-associated genes refutes the active participation of Dnmt1 in the transcriptional regulation of genes in the early developmental period. Instead, Dnmt1 was found to associate with genomic retroelements in a greatly biased fashion, particularly with the LINE1 (long interspersed nuclear elements) and ERVK (endogenous retrovirus type K) sequences. Transcriptomic analysis revealed that the transcripts of the Dnmt1-enriched retroelements were overrepresented in Dnmt1 knockdown embryos. Finally, methyl-CpG-binding domain sequencing proved that the Dnmt1-enriched retroelements, which were densely methylated in wild-type embryos, became demethylated in the Dnmt1-depleted embryos. Our results indicate that Dnmt1 is involved in the repression of retroelements through DNA methylation in early mouse development.

Anti-silencing factor 1A is associated with genome stability maintenance of mouse preimplantation embryos†

2020 ◽  
Vol 102 (4) ◽  
pp. 817-827
Author(s):  
Kai Deng ◽  
Wanyou Feng ◽  
Xiaohua Liu ◽  
Xiaoping Su ◽  
Erwei Zuo ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Genome Stability ◽  
Mouse Embryos ◽  
Preimplantation Embryos ◽  
End Joining ◽  
Dna Damages ◽  
Developmental Potential ◽  
Damage Repair ◽  
Non Homologous End Joining ◽  
Early Mouse

Abstract Genome stability is critical for the normal development of preimplantation embryos, as DNA damages may result in mutation and even embryo lethality. Anti-silencing factor 1A (ASF1A) is a histone chaperone and enriched in the MII oocytes as a maternal factor, which may be associated with the maintenance of genome stability. Thus, this study was undertaken to explore the role of ASF1A in maintaining the genome stability of early mouse embryos. The ASF1A expressed in the preimplantation embryos and displayed a dynamic pattern throughout the early embryonic development. Inhibition of ASF1A expression decreased embryonic development and increased DNA damages. Overexpression of ASF1A improved the developmental potential and decreased DNA damages. When 293T cells that had been integrated with RGS-NHEJ were co-transfected with plasmids of pcDNA3.1-ASF1A, gRNA-NHEJ, and hCas9, less cells expressed eGFP, indicating that non-homologous end joining was reduced by ASF1A. When 293T cells were co-transfected with plasmids of HR-donor, gRNA-HR, hCas9, and pcDNA3.1-ASF1A, more cells expressed eGFP, indicating that homologous recombination (HR) was enhanced by ASF1A. These results indicate that ASF1A may be associated with the genome stability maintenance of early mouse embryos and this action may be mediated by promoting DNA damage repair through HR pathway.

Focal adhesion kinase PTK2 autophosphorylation is not required for the activation of sodium–hydrogen exchange by decreased cell volume in the preimplantation mouse embryo

Zygote ◽  
2019 ◽  
Vol 27 (3) ◽  
pp. 173-179
Author(s):  
Jane C. Fenelon ◽  
Baozeng Xu ◽  
Jay M. Baltz
Keyword(s):  
Focal Adhesion Kinase ◽  
Cell Volume ◽  
Focal Adhesion ◽  
Mouse Embryo ◽  
Hydrogen Exchange ◽  
Cell Types ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Early Embryos ◽  
Early Mouse

SummaryRecovery from decreased cell volume is accomplished by a regulated increase of intracellular osmolarity. The acute response is activation of inorganic ion transport into the cell, the main effector of which is the Na+/H+ exchanger NHE1. NHE1 is rapidly activated by a cell volume decrease in early embryos, but how this occurs is incompletely understood. Elucidating cell volume-regulatory mechanisms in early embryos is important, as it has been shown that their dysregulation results in preimplantation developmental arrest. The kinase JAK2 has a role in volume-mediated NHE1 activation in at least some cells, including 2-cell stage mouse embryos. However, while 2-cell embryos show partial inhibition of NHE1 when JAK2 activity is blocked, NHE1 activation in 1-cell embryos is JAK2-independent, implying a requirement for additional signalling mechanisms. As focal adhesion kinase (FAK aka PTK2) becomes phosphorylated and activated in some cell types in response to decreased cell volume, we sought to determine whether it was involved in NHE1 activation in the early mouse embryo. FAK activity requires initial autophosphorylation of a tyrosine residue, Y397. However, FAK Y397 phosphorylation levels were not increased in either 1- or 2-cell embryos after cell volume was decreased. Furthermore, the selective FAK inhibitor PF-562271 did not affect NHE1 activation at concentrations that essentially eliminated Y397 phosphorylation. Thus, autophosphorylation of FAK Y397 does not appear to be required for NHE1 activation induced by a decrease in cell volume in early mouse embryos.

DNA methylation pattern in mouse oocytes and their in vitro fertilized early embryos: effect of oocyte vitrification

Zygote ◽  
2012 ◽  
Vol 22 (2) ◽  
pp. 138-145 ◽  
Author(s):  
Ying Liang ◽  
Xiang-Wei Fu ◽  
Jun-Jie Li ◽  
Dian-Shuai Yuan ◽  
Shi-En Zhu
Keyword(s):  
Dna Methylation ◽  
Fluorescein Isothiocyanate ◽  
Methylation Pattern ◽  
Oocyte Vitrification ◽  
Developmental Potential ◽  
Mouse Oocytes ◽  
Early Embryos ◽  
Vitrification Solution ◽  
Early Mouse

SummaryThis study was conducted to investigate the pattern of DNA methylation in vitrified–thawed mouse oocytes and their in vitro fertilized early embryos. Firstly, mouse oocytes at metaphase II (MII) stage of meiosis were allocated randomly into three groups: (1) untreated (control); (2) exposed to vitrification solution without being plunged into liquid nitrogen (toxicity); or (3) vitrified by open-pulled straw (OPS) method (vitrification). Oocytes from all three groups were fertilized subsequently in vitro. The level of DNA methylation in the MII oocytes and their early embryos was then examined by immunofluorescence using an anti-5-methylcytosine (anti-5-MeC) monoclonal antibody and fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. Developmental rates to 2-cell embryos (62.28%) and blastocysts (43.68%) of the vitrified–thawed oocytes were lower (P < 0.01) than those of fresh oocytes (81.47%, 61.99%) and vitrification solution treated (79.20%, 60.04%) oocytes. DNA methylation (as reflected by 5-MeC fluorescence intensity) in the vitrification group was less (P < 0.01) for MII oocyte and 2- to 8-cell stages compared with that in the control and toxicity groups. Accordingly, a reduction in global genomic methylation due to vitrification of MII oocytes may result in compromised in vitro developmental potential in early mouse embryos.

scholarly journals Gamete imprinting: setting epigenetic patterns for the next generation

2006 ◽  
Vol 18 (2) ◽  
pp. 63 ◽  
Author(s):  
Jacquetta M. Trasler
Keyword(s):  
Dna Methylation ◽  
Genomic Dna ◽  
Germ Line ◽  
Imprinted Genes ◽  
Specific Expression ◽  
Placental Function ◽  
Early Embryos ◽  
Parent Of Origin ◽  
Methylation Patterns ◽  
Epigenetic Patterns

The acquisition of genomic DNA methylation patterns, including those important for development, begins in the germ line. In particular, imprinted genes are differentially marked in the developing male and female germ cells to ensure parent-of-origin-specific expression in the offspring. Abnormalities in imprints are associated with perturbations in growth, placental function, neurobehavioural processes and carcinogenesis. Based, for the most part, on data from the well-characterised mouse model, the present review will describe recent studies on the timing and mechanisms underlying the acquisition and maintenance of DNA methylation patterns in gametes and early embryos, as well as the consequences of altering these patterns.

61 Expression Profiles and Functional Roles of H3.3 and HIRA in Bovine Early Embryos

2018 ◽  
Vol 30 (1) ◽  
pp. 169
Author(s):  
K. Zhang ◽  
H. Wang
Keyword(s):  
Embryonic Development ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Mrna Level ◽  
Histone H3 ◽  
Specific Pattern ◽  
Early Embryonic Development ◽  
Early Embryos ◽  
Zygote Development

Early embryo death is one major reason for poor reproductive efficiency in dairy cows. In particular, ~20 to 50% of high-producing cows are subject to pregnancy loss during the first week of gestation, indicating the importance of embryonic development from fertilization to the blastocyst stage. To highlight this importance, multiple critical molecular and developmental events, including zygote reprogramming, maternal RNA decay, and embryonic genome activation, occur during bovine pre-implantation development. However, the molecular mechanisms of these events have yet to be defined. H3.3 is a histone H3 variant that encoded by 2 genes, namely, H3F3A and H3F3B. It is generally believed that H3.3 is closely related to active transcribed genes. Of interest, H3.3 required for establishing proper chromatin structure during mouse oogenesis. Immediately following fertilization, H3.3 is incorporated to parental chromatins and essential for blastocyst formation in mice. HIRA is a chaperone for H3.3 deposition and indispensable for zygote development. Previously, our results showed that H3.3 is needed for bovine early embryonic development. Herein, experiments were designed to determine the mechanisms of functional requirement of H3.3 in bovine early embryos. Slaughterhouse-derived cumulus–oocyte complexes (COC) were matured in vitro and IVF was performed. To knock down genes of interest, small interfering (si)RNAs were delivered into zygotes via microinjection. The qPCR results showed that H3F3A mRNA level is stable, whereas H3F3B and HIRA mRNA are dynamic during early embryonic development (4 replicates). The mRNA abundance of H3F3B is significantly higher than that of H3F3A (4 replicates; P < 0.05), which is also found in mouse and human. Immunostaining results revealed a stage-specific pattern for the localization of H3.3 in bovine early embryos, and the H3.3 signal was not different between paternal and maternal pronuclei in zygotes, which was different from the pattern in mice. The siRNA-mediated silencing of H3.3 dramatically reduces the expression of CTGF (a putative trophectoderm marker) in bovine blastocysts (3 replicates; P < 0.05). Furthermore, we found that the signal intensity of dimethylation of histone H3 lysine 36 (H3K36me2) and linker histone H1 decreases in H3.3-ablated embryos, which is similar to CHD1 knockdown (3 replicates; P < 0.05). However, no difference was found for the intensity of trimethylation of histone H3 lysine 4, dimethylation of histone H3 lysine 9 (H3K9me2) and splicing factor 3 B1 (SF3B1). We also found that HIRA deletion does not affect bovine early embryonic development. Taken together, the results described herein suggest that H3.3 is required for proper epigenetic modifications and H1 deposition during bovine early embryonic development. This project was supported by National Natural Science Foundation of China grant (No. 31672416) and the Fundamental Research Funds for the Central Universities.

scholarly journals Maternal tamoxifen treatment expands the macrophage population of early mouse embryos

2018 ◽  
Author(s):  
Rocío Rojo ◽  
Kristin A. Sauter ◽  
Lucas Lefevre ◽  
David A. Hume ◽  
Clare Pridans
Keyword(s):  
Mononuclear Phagocyte ◽  
Mouse Embryos ◽  
Tamoxifen Treatment ◽  
Macrophage Population ◽  
Large Expansion ◽  
Pregnant Mice ◽  
Early Mouse ◽  
Leukocyte Populations ◽  
Whole Mounts ◽  
Macrophage Lineage

AbstractSeveral different transgenic tamoxifen-inducible cre reporter lines have been used to analyse the contribution of embryonic precursors to the development of the mononuclear phagocyte system in mice. Here we show that tamoxifen treatment of the mother at 8.5dpc with doses commonly-used in lineage trace studies produces a 4-5-fold expansion of the embryonic leukocyte populations by 10.5dpc, detected in whole mounts of embryos using aCsf1rreporter gene or separately by expression ofCsf1r, Itgam(CD11b),Adgre1(F4/80) orPtprc(CD45) mRNA. These findings indicate that tamoxifen cannot be considered a neutral agonist in macrophage lineage trace studies.Summary sentenceTreatment of pregnant mice with tamoxifen in early gestation produces a large expansion of the embryonic macrophage population.

261 INFLUENCE OF IN VITRO MATURATION ON EPIGENETIC MARKS AND GENE EXPRESSION IN BOVINE OOCYTES

2011 ◽  
Vol 23 (1) ◽  
pp. 228
Author(s):  
J. Heinzmann ◽  
T. Hansmann ◽  
C. Wrenzycki ◽  
U. Zechner ◽  
T. Haaf ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Embryonic Development ◽  
Quantitative Pcr ◽  
Assisted Reproduction ◽  
In Vitro Maturation ◽  
Imprinted Genes ◽  
Assisted Reproduction Technology ◽  
Bovine Oocytes

In cattle, in vitro maturation (IVM) of oocytes is an integral part of assisted reproduction technology. However, only 30% of in vitro matured bovine oocytes develop to the blastocyst stage after fertilization (compared with 60% for in vivo matured oocytes), indicating critical involvement of maturation conditions in the developmental competence of oocytes. Oocytes for IVF and intracytoplasmic sperm injection in humans are typically allowed to mature in vivo after superovulation because IVM is not considered to be a safe medical procedure. Several studies have shown that assisted reproduction technology involving prolonged in vitro culture of human and ruminant embryos can be associated with increased risk of fetal or placental abnormalities due to aberrant DNA methylation of imprinted and non-imprinted genes. Similarities between the bovine large offspring syndrome and imprinting-related human Beckwith–Wiedemann syndrome and the general similarity of bovine and human pre-implantation development make bovine oocyte maturation and embryonic development an increasingly accepted model of human development. Differentially methylated regions and imprinting control regions for the bovine paternally imprinted gene H19 and the maternally imprinted genes PEG3 and SNRPN were identified and characterised in this study. The DNA methylation profiles of bovine oocytes could be determined by bisulfite treatment of DNA from pools of 10 oocytes, but no significant differences were observed between IVM in TCM medium with 20% O2, in SOF medium with 5% O2, or after in vivo maturation. In contrast, quantitative PCR analysis of single oocyte preparations (n ≥ 8) revealed significant differences between these groups in the expression of the 3 genes. We then investigated the expression of genes involved in other critical processes in the developing oocyte and early embryo by quantitative PCR, including SLC2A8 (glucose transport), GDF9 (growth factor), PRDX1 (antioxidant and intercellular communication), DNMT1a/b (maintenance of methylation), and DNMT3a/b (de novo methylation). We also studied IGF2R, an imprinted gene implicated in large offspring syndrome. We observed significant differences in the expression of several of these genes. Interestingly, the expression of DNMT3a and DNMT3b was significantly higher in in vitro matured oocytes than in in vivo matured oocytes and could result in the above-mentioned aberrant methylation patterns established later in embryonic development. This work was funded by DFG (FOR1041).

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