112 EXPRESSION OF DNA METHYLTRANSFERASES (DNMT) IN PLACENTAL TISSUES DURING EARLY PREGNANCY IN SHEEP

2011 ◽  
Vol 23 (1) ◽  
pp. 161
Author(s):  
A. T. Grazul-Bilska ◽  
M. L. Johnson ◽  
P. P. Borowicz ◽  
D. A. Redmer ◽  
L. P. Reynolds

Normal placental development is critical for placental function and thus for normal embryonic and fetal growth and development. Many factors, including those from the environment or from the application of assisted reproductive techniques, are known to affect embryonic development. Additionally, altered DNA methylation was reported for fetal and/or maternal placenta from compromised pregnancies, and this may contribute to high embryonic/fetal loss. DNA methylation regulated by DNA methyltransferase (DNMT) plays an important role during embryonic development. However, little is known about the expression of DNMT in placental tissues during early pregnancy in any species. To determine the mRNA expression of DNMT 3a and 3b (developmentally-regulated DNMT) in normal placenta, caruncular (CAR, maternal placenta) tissue and fetal membranes (FM, chorioallantois or fetal placenta) were collected on Days 14, 16, 18, 20, 22, 24, 26, 28, and 30 after natural mating (n = 5–8 ewes day–1) and on Day 9–11 after oestrus (n = 7; non-pregnant [NP] controls, CAR only), snap-frozen, and then used for quantitative real time RT-PCR. For each tissue, data were analysed statistically by ANOVA with the day of pregnancy as the main effect. In CAR and FM, mRNA expression of DNMT3A and 3b was affected (P < 0.01–0.02) by day of pregnancy. In CAR, expression of DNMT3A was similar in NP controls and on days 14, 16, 18, and 30, was decreased (P < 0.01) ∼2-fold on day 20, and then gradually increased to day 30 of pregnancy. In CAR, expression of DNMT3b was similar in NP controls and on days 14, 16, 18, 24, 26, and 28, but was greater (P < 0.02) by ∼2-fold on days 22 and 30 than in NP controls or on days 24 and 26 of pregnancy. For CAR, regression analysis of DNMT3a mRNA expression demonstrated a cubic pattern (R2 = 0.253; P = 0.01) of expression during early pregnancy. In FM, DNMT3a increased (P < 0.01) ∼2-fold from day 16 to 24–30, but DNMT3b gradually decreased (∼0.5–5-fold; P < 0.01) from day 16 to day 30 of pregnancy. For FM, regression analysis of mRNA expression for DNMT3a demonstrated a linear increase (R2 = 0.301; P < 0.01), but for DNMT3b a cubic pattern (R2 = 0.624; P < 0.01) of expression during early pregnancy. These data indicate that DNMT3a and 3b mRNA are differentially expressed in CAR and FM, and the temporal pattern of expression of DNMT3a and 3b differs between maternal and fetal placental tissues during early pregnancy in sheep. Thus, significant changes in mRNA expression of DNMT3a and 3b in CAR and FM indicate that de novo methylation is present in the placenta during early pregnancy in sheep and may be regulated in part by the level of DNMT expression. These data provide a foundation for determining the basis for altered DNA methylation of placental and embryonic tissues in compromised pregnancies. Supported by USDA grant 2007-01215 to LPR and ATGB, and NIH grant HL64141 to LPR and DAR.

2020 ◽  
Vol 48 (7) ◽  
pp. 3949-3961 ◽  
Author(s):  
Chien-Chu Lin ◽  
Yi-Ping Chen ◽  
Wei-Zen Yang ◽  
James C K Shen ◽  
Hanna S Yuan

Abstract DNA methyltransferases are primary enzymes for cytosine methylation at CpG sites of epigenetic gene regulation in mammals. De novo methyltransferases DNMT3A and DNMT3B create DNA methylation patterns during development, but how they differentially implement genomic DNA methylation patterns is poorly understood. Here, we report crystal structures of the catalytic domain of human DNMT3B–3L complex, noncovalently bound with and without DNA of different sequences. Human DNMT3B uses two flexible loops to enclose DNA and employs its catalytic loop to flip out the cytosine base. As opposed to DNMT3A, DNMT3B specifically recognizes DNA with CpGpG sites via residues Asn779 and Lys777 in its more stable and well-ordered target recognition domain loop to facilitate processive methylation of tandemly repeated CpG sites. We also identify a proton wire water channel for the final deprotonation step, revealing the complete working mechanism for cytosine methylation by DNMT3B and providing the structural basis for DNMT3B mutation-induced hypomethylation in immunodeficiency, centromere instability and facial anomalies syndrome.


Reproduction ◽  
2011 ◽  
Vol 141 (4) ◽  
pp. 529-540 ◽  
Author(s):  
Anna T Grazul-Bilska ◽  
Mary Lynn Johnson ◽  
Pawel P Borowicz ◽  
Megan Minten ◽  
Jerzy J Bilski ◽  
...  

To characterize early fetal placental development, gravid uterine tissues were collected from pregnant ewes every other day from day 16 to 30 after mating. Determination of 1) cell proliferation was based on Ki67 protein immunodetection; 2) global methylation was based on 5-methyl-cytosine (5mC) expression and mRNA expression for DNA methyltransferases (DNMTs)1,3a, and3b; and 3) vascular development was based on smooth muscle cell actin immunolocalization and on mRNA expression of several factors involved in the regulation of angiogenesis in fetal membranes (FMs). Throughout early pregnancy, the labeling index (proportion of proliferating cells) was very high (21%) and did not change. Expression of 5mC and mRNA forDNMT3bdecreased, but mRNA forDNMT1and3aincreased. Blood vessels were detected in FM on days 18–30 of pregnancy, and their number per tissue area did not change. The patterns of mRNA expression for placental growth factor, vascular endothelial growth factor, and their receptorsFLT1andKDR; angiopoietins 1 and 2 and their receptorTEK; endothelial nitric oxide synthase and the NO receptorGUCY13B; and hypoxia inducing factor 1 α changed in FM during early pregnancy. These data demonstrate high cellular proliferation rates, and changes in global methylation and mRNA expression of factors involved in the regulation of DNA methylation and angiogenesis in FM during early pregnancy. This description of cellular and molecular changes in FM during early pregnancy will provide the foundation for determining the basis of altered placental development in pregnancies compromised by environmental, genetic, or other factors.


2017 ◽  
Vol 29 (8) ◽  
pp. 1499 ◽  
Author(s):  
A. Franczak ◽  
K. Zglejc ◽  
E. Waszkiewicz ◽  
B. Wojciechowicz ◽  
M. Martyniak ◽  
...  

Female undernutrition during early pregnancy may affect the physiological pattern of genomic DNA methylation. We hypothesised that in utero DNA methylation may be impaired in females fed a restrictive diet in early pregnancy. In this study we evaluated whether poor maternal nutritional status, induced by applying a restricted diet during the peri-conceptional period, may influence: (1) the potential for in utero DNA methylation, expressed as changes in the mRNA expression and protein abundance of methyltransferases: DNA methyltransferase 1 (DNMT1) and DNMT3a in the endometrium and the myometrium, (2) the intrauterine microenvironment, measured as oestradiol 17β (E2) and progesterone (P4) concentrations in uterine flushings and (3) plasma concentration of E2 and P4 during the peri-implantation period. Our results indicate that maternal peri-conceptional undernutrition affects maintenance and de novo DNA methylation in the endometrium, de novo methylation in the myometrium and a results in a decrease in intrauterine E2 concentration during the peri-implantation period. The intrauterine concentration of P4 and plasma concentrations of E2 and P4 did not change. These findings suggest that undernutrition during the earliest period of pregnancy, and perhaps the pre-pregnancy period, may create changes in epigenetic mechanisms in the uterus and intrauterine milieu of E2 during the peri-implantation period.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Roza H. Ali Masalmeh ◽  
Francesca Taglini ◽  
Cristina Rubio-Ramon ◽  
Kamila I. Musialik ◽  
Jonathan Higham ◽  
...  

AbstractThe aberrant gain of DNA methylation at CpG islands is frequently observed in colorectal tumours and may silence the expression of tumour suppressors such as MLH1. Current models propose that these CpG islands are targeted by de novo DNA methyltransferases in a sequence-specific manner, but this has not been tested. Using ectopically integrated CpG islands, here we find that aberrantly methylated CpG islands are subject to low levels of de novo DNA methylation activity in colorectal cancer cells. By delineating DNA methyltransferase targets, we find that instead de novo DNA methylation activity is targeted primarily to CpG islands marked by the histone modification H3K36me3, a mark associated with transcriptional elongation. These H3K36me3 marked CpG islands are heavily methylated in colorectal tumours and the normal colon suggesting that de novo DNA methyltransferase activity at CpG islands in colorectal cancer is focused on similar targets to normal tissues and not greatly remodelled by tumourigenesis.


2020 ◽  
Author(s):  
D Kaplun ◽  
G Filonova ◽  
Y. Lobanova ◽  
A Mazur ◽  
S Zhenilo

ABSTRACTGain and loss of DNA methylation in cells is a dynamic process that tends to achieve an equilibrium. Many factors are involved in maintaining the balance between DNA methylation and demethylation. Previously, it was shown that methyl-DNA protein Kaiso may attract NcoR, SMRT repressive complexes affecting histone modifications. On the other hand, the deficiency of Kaiso resulted in slightly reduced methylation of ICR in H19/Igf2 locus and Oct4 promoter in mouse embryonic fibroblasts. However, nothing is known whether Kaiso may attract DNA methyltransferase to influence DNA methylation level. The main idea of this work is that Kaiso may lead to DNA hypermethylation attracting de novo DNA methyltransferases. We demonstrated that Kaiso regulates TRIM25 promoter methylation. It can form a complex with DNMT3b. BTB/POZ domain of Kaiso and ADD domain of DNA methyltransferase are essential for complex formation. Thus, Kaiso can affect DNA methylation.


Genes ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 617 ◽  
Author(s):  
Marthe Laisné ◽  
Nikhil Gupta ◽  
Olivier Kirsh ◽  
Sriharsa Pradhan ◽  
Pierre-Antoine Defossez

DNA methylation is an essential epigenetic mark in mammals. The proper distribution of this mark depends on accurate deposition and maintenance mechanisms, and underpins its functional role. This, in turn, depends on the precise recruitment and activation of de novo and maintenance DNA methyltransferases (DNMTs). In this review, we discuss mechanisms of recruitment of DNMTs by transcription factors and chromatin modifiers—and by RNA—and place these mechanisms in the context of biologically meaningful epigenetic events. We present hypotheses and speculations for future research, and underline the fundamental and practical benefits of better understanding the mechanisms that govern the recruitment of DNMTs.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1181-1181
Author(s):  
Pierre-Jacques Hamard ◽  
Luisa Luciani ◽  
Fan Liu ◽  
Guoyan Cheng ◽  
Megan A. Hatlen ◽  
...  

Abstract The shift in sites of hematopoiesis during embryonic development leads to primitive hematopoiesis within the fetal liver at E12.5, which generates primarily erythrocytes. Definitive hematopoiesis, which occurs within the bone marrow, follows at birth. During the erythroid differentiation of fetal hematopoiesis, progenitor cell maturation is accompanied by global DNA demethylation, a process necessary for fetal liver erythrocyte formation and accompanied by diminishing expression of the de novo DNA methyltransferases, Dnmt3a and Dnmt3b. In our current study of hematopoietic cell specific Prmt5 knockout mice, we have identified Prmt5 as a master regulator of erythropoiesis; the cell-specific deletion of Prmt5 in fetal liver cells is embryonic lethal as Prmt5-null embryos have severe anemia and increased expression of Dnmt3a and Dnmt3b proteins. RNA-seq and pathway analysis studies revealed profound defects in several critical pathways that regulate normal hematopoiesis, including the tumor suppressor p53 pathway. Methyl-seq studies are currently being conducted to determine the effects of the enforced expression of key DNA methyltransferases on global DNA methylation and gene expression in erythroid progenitors and how it leads to a block in erythrocyte maturation. To decipher the extent of Dnmt3a or p53's involvement in the observed phenotypes, we have generated double knockout mouse models that are being analyzed. Mechanistically, p53 has been shown to be directly methylated by Prmt5, a modification that affects its tumor suppressor activity. Here we have found that Dnmt3a is also a substrate of Prmt5 and the effects of the di methylation of Dnmt3a on its function are currently under investigation. Thus, we have uncovered a potential functional interaction between DNA methylation and protein arginine methylation triggered by Prmt5 that regulates primitive erythropoiesis. Disclosures Levine: Foundation Medicine: Consultancy; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees.


2021 ◽  
Vol 22 (7) ◽  
pp. 3735
Author(s):  
Guillaume Velasco ◽  
Damien Ulveling ◽  
Sophie Rondeau ◽  
Pauline Marzin ◽  
Motoko Unoki ◽  
...  

DNA methylation (DNAme) profiling is used to establish specific biomarkers to improve the diagnosis of patients with inherited neurodevelopmental disorders and to guide mutation screening. In the specific case of mendelian disorders of the epigenetic machinery, it also provides the basis to infer mechanistic aspects with regard to DNAme determinants and interplay between histone and DNAme that apply to humans. Here, we present comparative methylomes from patients with mutations in the de novo DNA methyltransferases DNMT3A and DNMT3B, in their catalytic domain or their N-terminal parts involved in reading histone methylation, or in histone H3 lysine (K) methylases NSD1 or SETD2 (H3 K36) or KMT2D/MLL2 (H3 K4). We provide disease-specific DNAme signatures and document the distinct consequences of mutations in enzymes with very similar or intertwined functions, including at repeated sequences and imprinted loci. We found that KMT2D and SETD2 germline mutations have little impact on DNAme profiles. In contrast, the overlapping DNAme alterations downstream of NSD1 or DNMT3 mutations underlines functional links, more specifically between NSD1 and DNMT3B at heterochromatin regions or DNMT3A at regulatory elements. Together, these data indicate certain discrepancy with the mechanisms described in animal models or the existence of redundant or complementary functions unforeseen in humans.


Nature Plants ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 184-197
Author(s):  
Jianjun Jiang ◽  
Jie Liu ◽  
Dean Sanders ◽  
Shuiming Qian ◽  
Wendan Ren ◽  
...  

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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