scholarly journals Construction of Differential-Methylation Subtractive Library

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Hu ◽  
Xiaolei Liang ◽  
Tian Dong ◽  
Yanfeng Hu ◽  
Jie Liu ◽  
...  

Stress-induced ROS changes DNA methylation patterns. A protocol combining methylation-sensitive restriction endonuclease (MS-RE) digestion with suppression subtractive hybridization (SSH) to construct the differential-methylation subtractive library was developed for finding genes regulated by methylation mechanism under cold stress. The total efficiency of target fragment detection was 74.64%. DNA methylation analysis demonstrated the methylation status of target fragments changed after low temperature or DNA methyltransferase inhibitor treatment. Transcription level analysis indicated that demethylation of DNA promotes gene expression level. The results proved that our protocol was reliable and efficient to obtain gene fragments in differential-methylation status.

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jessilyn Dunn ◽  
Haiwei Qiu ◽  
Soyeon Kim ◽  
Daudi Jjingo ◽  
Ryan Hoffman ◽  
...  

Atherosclerosis preferentially occurs in arterial regions of disturbed blood flow (d-flow), which alters gene expression, endothelial function, and atherosclerosis. Here, we show that d-flow regulates genome-wide DNA methylation patterns in a DNA methyltransferase (DNMT)-dependent manner. We found that d-flow induced expression of DNMT1, but not DNMT3a or DNMT3b, in mouse arterial endothelium in vivo and in cultured endothelial cells by oscillatory shear (OS) compared to unidirectional laminar shear in vitro. The DNMT inhibitor 5-Aza-2’deoxycytidine (5Aza) or DNMT1 siRNA significantly reduced OS-induced endothelial inflammation. Moreover, 5Aza reduced lesion formation in two atherosclerosis models using ApoE-/- mice (western diet for 3 months and the partial carotid ligation model with western diet for 3 weeks). To identify the 5Aza mechanisms, we conducted two genome-wide studies: reduced representation bisulfite sequencing (RRBS) and transcript microarray using endothelial-enriched gDNA and RNA, respectively, obtained from the partially-ligated left common carotid artery (LCA exposed to d-flow) and the right contralateral control (RCA exposed to s-flow) of mice treated with 5Aza or vehicle. D-flow induced DNA hypermethylation in 421 gene promoters, which was significantly prevented by 5Aza in 335 genes. Systems biological analyses using the RRBS and the transcriptome data revealed 11 mechanosensitive genes whose promoters were hypermethylated by d-flow but rescued by 5Aza treatment. Of those, five genes contain hypermethylated cAMP-response-elements in their promoters, including the transcription factors HoxA5 and Klf3. Their methylation status could serve as a mechanosensitive master switch in endothelial gene expression. Our results demonstrate that d-flow controls epigenomic DNA methylation patterns in a DNMT-dependent manner, which in turn alters endothelial gene expression and induces atherosclerosis.


Author(s):  
Anna Hecht ◽  
Julia A. Meyer ◽  
Johann-Christoph Jann ◽  
Katja Sockel ◽  
Aristoteles Giagounidis ◽  
...  

AbstractMyelodysplastic syndrome (MDS) with isolated deletion of chromosome 5q (MDS del5q) is a distinct subtype of MDS with quite favorable prognosis and excellent response to treatment with lenalidomide. Still, a relevant percentage of patients do not respond to lenalidomide and even experience progression to acute myeloid leukemia (AML). In this study, we aimed to investigate whether global DNA methylation patterns could predict response to lenalidomide. Genome-wide DNA methylation analysis using Illumina 450k methylation arrays was performed on n=51 patients with MDS del5q who were uniformly treated with lenalidomide in a prospective multicenter trial of the German MDS study group. To study potential direct effects of lenalidomide on DNA methylation, 17 paired samples pre- and post-treatment were analyzed. Our results revealed no relevant effect of lenalidomide on methylation status. Furthermore, methylation patterns prior to therapy could not predict lenalidomide response. However, methylation clustering identified a group of patients with a trend towards inferior overall survival. These patients showed hypermethylation of several interesting target genes, including genes of relevant signaling pathways, potentially indicating the evaluation of novel therapeutic targets.


2020 ◽  
Vol 21 (18) ◽  
pp. 6844
Author(s):  
Aneta M. Dobosz ◽  
Justyna Janikiewicz ◽  
Anna M. Borkowska ◽  
Anna Dziewulska ◽  
Ewelina Lipiec ◽  
...  

Metabolic stress, such as lipotoxicity, affects the DNA methylation profile in pancreatic β-cells and thus contributes to β-cell failure and the progression of type 2 diabetes (T2D). Stearoyl-CoA desaturase 1 (SCD1) is a rate-limiting enzyme that is involved in monounsaturated fatty acid synthesis, which protects pancreatic β-cells against lipotoxicity. The present study found that SCD1 is also required for the establishment and maintenance of DNA methylation patterns in β-cells. We showed that SCD1 inhibition/deficiency caused DNA hypomethylation and changed the methyl group distribution within chromosomes in β-cells. Lower levels of DNA methylation in SCD1-deficient β-cells were followed by lower levels of DNA methyltransferase 1 (DNMT1). We also found that the downregulation of SCD1 in pancreatic β-cells led to the activation of adenosine monophosphate-activated protein kinase (AMPK) and an increase in the activity of the NAD-dependent deacetylase sirtuin-1 (SIRT1). Furthermore, the physical association between DNMT1 and SIRT1 stimulated the deacetylation of DNMT1 under conditions of SCD1 inhibition/downregulation, suggesting a mechanism by which SCD1 exerts control over DNMT1. We also found that SCD1-deficient β-cells that were treated with compound c, an inhibitor of AMPK, were characterized by higher levels of both global DNA methylation and DNMT1 protein expression compared with untreated cells. Therefore, we found that activation of the AMPK/SIRT1 signaling pathway mediates the effect of SCD1 inhibition/deficiency on DNA methylation status in pancreatic β-cells. Altogether, these findings suggest that SCD1 is a gatekeeper that protects β-cells against the lipid-derived loss of DNA methylation and provide mechanistic insights into the mechanism by which SCD1 regulates DNA methylation patterns in β-cells and T2D-relevant tissues.


2004 ◽  
Vol 24 (4) ◽  
pp. 1640-1648 ◽  
Author(s):  
F. Gaudet ◽  
W. M. Rideout ◽  
A. Meissner ◽  
J. Dausman ◽  
H. Leonhardt ◽  
...  

ABSTRACT The methylation of intracisternal A-type particle (IAP) sequences is maintained during mouse embryogenesis. Methylation suppresses IAP expression and the potential for mutagenesis by retrotransposition, but it is not clear how methylation of these elements is maintained during the embryonic stages when the bulk of the genome is being demethylated. It has been suggested that the high levels of DNA methyltransferase-1 (Dnmt1) present during cleavage could be important for keeping IAPs methylated. To test this hypothesis, we combined mutant alleles of Dnmt1 with an agouti allele (Aiapy ), which provided a coat color readout for the methylation status of the IAP insertion in the agouti locus. We found that reduction in Dnmt1 levels directly impacted methylation at this locus, leading to stable transcriptional activation of the agouti gene in the adult. Specifically, the short maternal Dnmt1 protein was important in maintaining methylation at the Aiapy locus in cleavage embryos, whereas the longer Dnmt1 isoform found in somatic cells was important in maintaining IAP methylation during the postimplantation stage. These results underscore the importance of maintaining proper maintenance of methylation patterns during gestation and suggest that interference with this process may stably affect gene expression patterns in the adult and may have profound phenotypic consequences.


Endocrinology ◽  
2009 ◽  
Vol 150 (10) ◽  
pp. 4681-4691 ◽  
Author(s):  
Aparna Mahakali Zama ◽  
Mehmet Uzumcu

Abstract Exposure to endocrine-disrupting chemicals during development could alter the epigenetic programming of the genome and result in adult-onset disease. Methoxychlor (MXC) and its metabolites possess estrogenic, antiestrogenic, and antiandrogenic activities. Previous studies showed that fetal/neonatal exposure to MXC caused adult ovarian dysfunction due to altered expression of key ovarian genes including estrogen receptor (ER)-β, which was down-regulated, whereas ERα was unaffected. The objective of the current study was to evaluate changes in global and gene-specific methylation patterns in adult ovaries associated with the observed defects. Rats were exposed to MXC (20 μg/kg·d or 100 mg/kg·d) between embryonic d 19 and postnatal d 7. We performed DNA methylation analysis of the known promoters of ERα and ERβ genes in postnatal d 50–60 ovaries using bisulfite sequencing and methylation-specific PCRs. Developmental exposure to MXC led to significant hypermethylation in the ERβ promoter regions (P < 0.05), whereas the ERα promoter was unaffected. We assessed global DNA methylation changes using methylation-sensitive arbitrarily primed PCR and identified 10 genes that were hypermethylated in ovaries from exposed rats. To determine whether the MXC-induced methylation changes were associated with increased DNA methyltransferase (DNMT) levels, we measured the expression levels of Dnmt3a, Dnmt3b, and Dnmt3l using semiquantitative RT-PCR. Whereas Dnmt3a and Dnmt3l were unchanged, Dnmt3b expression was stimulated in ovaries of the 100 mg/kg MXC group (P < 0.05), suggesting that increased DNMT3B may cause DNA hypermethylation in the ovary. Overall, these data suggest that transient exposure to MXC during fetal and neonatal development affects adult ovarian function via altered methylation patterns.


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.


2021 ◽  
Vol 43 (3) ◽  
pp. 1419-1435
Author(s):  
Walter Pulverer ◽  
Kristi Kruusmaa ◽  
Silvia Schönthaler ◽  
Jasmin Huber ◽  
Marko Bitenc ◽  
...  

Early diagnosis of colorectal cancer (CRC) is of high importance as prognosis depends on tumour stage at the time of diagnosis. Detection of tumour-specific DNA methylation marks in cfDNA has several advantages over other approaches and has great potential for solving diagnostic needs. We report here the identification of DNA methylation biomarkers for CRC and give insights in our methylation-sensitive restriction enzyme coupled qPCR (MSRE-qPCR) system. Targeted microarrays were used to investigate the DNA methylation status of 360 cancer-associated genes. Validation was done by qPCR-based approaches. A focus was on investigating marker performance in cfDNA from 88 patients (44 CRC, 44 controls). Finally, the workflow was scaled-up to perform 180plex analysis on 110 cfDNA samples, to identify a DNA methylation signature for advanced colonic adenomas (AA). A DNA methylation signature (n = 44) was deduced from microarray experiments and confirmed by quantitative methylation-specific PCR (qMSP) and by MSRE-qPCR, providing for six genes’ single areas under the curve (AUC) values of >0.85 (WT1, PENK, SPARC, GDNF, TMEFF2, DCC). A subset of the signatures can be used for patient stratification and therapy monitoring for progressed CRC with liver metastasis using cfDNA. Furthermore, we identified a 35-plex classifier for the identification of AAs with an AUC of 0.80.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Shir Toubiana ◽  
Miriam Gagliardi ◽  
Mariarosaria Papa ◽  
Roberta Manco ◽  
Maty Tzukerman ◽  
...  

DNA methyltransferase 3B (DNMT3B) is the major DNMT that methylates mammalian genomes during early development. Mutations in human DNMT3B disrupt genome-wide DNA methylation patterns and result in ICF syndrome type 1 (ICF1). To study whether normal DNA methylation patterns may be restored in ICF1 cells, we corrected DNMT3B mutations in induced pluripotent stem cells from ICF1 patients. Focusing on repetitive regions, we show that in contrast to pericentromeric repeats, which reacquire normal methylation, the majority of subtelomeres acquire only partial DNA methylation and, accordingly, the ICF1 telomeric phenotype persists. Subtelomeres resistant to de novo methylation were characterized by abnormally high H3K4 trimethylation (H3K4me3), and short-term reduction of H3K4me3 by pharmacological intervention partially restored subtelomeric DNA methylation. These findings demonstrate that the abnormal epigenetic landscape established in ICF1 cells restricts the recruitment of DNMT3B, and suggest that rescue of epigenetic diseases with genome-wide disruptions will demand further manipulation beyond mutation correction.


The Analyst ◽  
2016 ◽  
Vol 141 (2) ◽  
pp. 579-584 ◽  
Author(s):  
Weiting Zhang ◽  
Xiaolong Zu ◽  
Yanling Song ◽  
Zhi Zhu ◽  
Chaoyong James Yang

Abnormal DNA methylation patterns caused by altered DNA methyltransferase (MTase) activity are closely associated with cancer. Herein, using DNA adenine methylation methyltransferase (Dam MTase) as a model analyte, we designed an allosteric molecular beacon (aMB) for sensitive detection of Dam MTase activity.


Author(s):  
Chia-Feng Yang ◽  
Wilfried J. J. Karmaus ◽  
Chen-Chang Yang ◽  
Mei-Lien Chen ◽  
I-Jen Wang

Epidemiological studies have reported the relationship between bisphenol A (BPA) exposure and increased prevalence of asthma, but the mechanisms remain unclear. Here, we investigated whether BPA exposure and DNA methylation related to asthma in children. We collected urinary and blood samples from 228 children (Childhood Environment and Allergic Diseases Study cohort) aged 3 years. Thirty-three candidate genes potentially interacting with BPA exposure were selected from a toxicogenomics database. DNA methylation was measured in 22 blood samples with top-high and bottom-low exposures of BPA. Candidate genes with differential methylation levels were validated by qPCR and promoter associated CpG islands have been investigated. Correlations between the methylation percentage and BPA exposure and asthma were analyzed. According to our findings, MAPK1 showed differential methylation and was further investigated in 228 children. Adjusting for confounders, urinary BPA glucuronide (BPAG) level inversely correlated with MAPK1 promoter methylation (β = −0.539, p = 0.010). For the logistic regression analysis, MAPK1 methylation status was dichotomized into higher methylated and lower methylated groups with cut off continuous variable of median of promoter methylation percentage (50%) while performing the analysis. MAPK1 methylation was lower in children with asthma than in children without asthma (mean ± SD; 69.82 ± 5.88% vs. 79.82 ± 5.56%) (p = 0.001). Mediation analysis suggested that MAPK1 methylation acts as a mediation variable between BPA exposure and asthma. The mechanism of BPA exposure on childhood asthma might, therefore, be through the alteration of MAPK1 methylation. The mechanism of BPA exposure on childhood asthma might, therefore, be through the alteration of MAPK1 methylation.


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