scholarly journals A Long Polymorphic GT Microsatellite within a Gene Promoter Mediates Non-Imprinted Allele-Specific DNA Methylation of a CpG Island in a Goldfish Inter-Strain Hybrid

2019 ◽  
Vol 20 (16) ◽  
pp. 3923
Author(s):  
Zheng ◽  
Xu ◽  
Cao
Keyword(s):  
Dna Methylation ◽  
Cpg Island ◽  
Methylation Status ◽  
Repetitive Sequences ◽  
Gene Promoter ◽  
Dna Polymorphisms ◽  
Specific Expression ◽  
Cis Acting ◽  
Allele Specific ◽  
The Impact

It is now widely accepted that allele-specific DNA methylation (ASM) commonly occurs at non-imprinted loci. Most of the non-imprinted ASM regions observed both within and outside of the CpG island show a strong correlation with DNA polymorphisms. However, what polymorphic cis-acting elements mediate non-imprinted ASM of the CpG island remains unclear. In this study, we investigated the impact of polymorphic GT microsatellites within the gene promoter on non-imprinted ASM of the local CpG island in goldfish. We generated various goldfish heterozygotes, in which the length of GT microsatellites or some non-repetitive sequences in the promoter of no tail alleles was different. By examining the methylation status of the downstream CpG island in these heterozygotes, we found that polymorphisms of a long GT microsatellite can lead to the ASM of the downstream CpG island during oogenesis and embryogenesis, polymorphisms of short GT microsatellites and non-repetitive sequences in the promoter exhibited no significant effect on the methylation of the CpG island. We also observed that the ASM of the CpG island was associated with allele-specific expression in heterozygous embryos. These results suggest that a long polymorphic GT microsatellite within a gene promoter mediates non-imprinted ASM of the local CpG island in a goldfish inter-strain hybrid.

scholarly journals Expression of Sclerostin in Osteoporotic Fracture Patients Is Associated with DNA Methylation in the CpG Island of the SOST Gene

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Yanming Cao ◽  
Bin Wang ◽  
Ding Wang ◽  
Dongxiang Zhan ◽  
Caiyuan Mai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Osteoporotic Fracture ◽  
Cpg Island ◽  
Epigenetic Modification ◽  
Methylation Status ◽  
Gene Promoter ◽  
Primary Osteoporosis ◽  
Sost Gene ◽  
Fracture Bone

Purpose. SOST gene is one of the key factors in regulating bone absorption. Although there are reports showing diverse transcription factors, epigenetic modification could be responsible for regulating SOST gene expression. There is still little exploration on promoter methylation status of SOST gene in osteoporotic bone tissues. The aim of this study is to investigate the involvement of CpG methylation in regulation of SOST expression in patients with primary osteoporosis. Methods. The diagnosis of osteoporosis was established on the basis of dual energy X-ray absorptiometry to measure BMD. All femoral bone tissues were separated in surgeries. After extracting total RNA and protein, we checked the relative expression levels of SOST by quantitative real-time PCR and western blot. Also, immunohistochemical staining was performed to observe the expression of SOST protein in the bone samples. The genomic DNA of non-OPF (non-osteoporotic fracture bone tissues) and OPF (osteoporotic fracture bone tissues) were treated by bisulfite modification, and methylation status of CpG sites in the CpG island of SOST gene promoter was determined by DNA sequencing. Results. SOST gene expression in the non-OPF group was lower than that in OPF group. Bisulfite sequencing result showed that SOST gene promoter was slightly demethylated in the OPF group, as compared with non-OPF group. Conclusion. Our study demonstrated that DNA methylation influenced the transcriptional expression of SOST gene, which probably may play an important role in the pathogenesis of primary osteoporosis.

scholarly journals Bumblebee Workers Show Differences in Allele-Specific DNA Methylation and Allele-Specific Expression

2020 ◽  
Vol 12 (8) ◽  
pp. 1471-1481
Author(s):  
Hollie Marshall ◽  
Alun R C Jones ◽  
Zoë N Lonsdale ◽  
Eamonn B Mallon
Keyword(s):  
Dna Methylation ◽  
Bombus Terrestris ◽  
Specific Expression ◽  
Allele Specific Expression ◽  
Cis Acting ◽  
Genome Wide ◽  
Expression Bias ◽  
Hymenopteran Species ◽  
Allele Specific ◽  
Allele Specific Methylation

Abstract Allele-specific expression is when one allele of a gene shows higher levels of expression compared with the other allele, in a diploid organism. Recent work has identified allele-specific expression in a number of Hymenopteran species. However, the molecular mechanism which drives this allelic expression bias remains unknown. In mammals, DNA methylation is often associated with genes which show allele-specific expression. DNA methylation systems have been described in species of Hymenoptera, providing a candidate mechanism. Using previously generated RNA-Seq and whole-genome bisulfite sequencing from reproductive and sterile bumblebee (Bombus terrestris) workers, we have identified genome-wide allele-specific expression and allele-specific DNA methylation. The majority of genes displaying allele-specific expression are common between reproductive and sterile workers and the proportion of allele-specific expression bias generally varies between genetically distinct colonies. We have also identified genome-wide allele-specific DNA methylation patterns in both reproductive and sterile workers, with reproductive workers showing significantly more genes with allele-specific methylation. Finally, there is no significant overlap between genes showing allele-specific expression and allele-specific methylation. These results indicate that cis-acting DNA methylation does not directly drive genome-wide allele-specific expression in this species.

scholarly journals Genome-wide analysis identifies critical DNA methylations within NTRKs genes in colorectal cancer

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Zijian Chen ◽  
Zenghong Huang ◽  
Yanxin Luo ◽  
Qi Zou ◽  
Liangliang Bai ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Dna Methylation ◽  
Promoter Methylation ◽  
Expression Profiles ◽  
Methylation Status ◽  
Gene Promoter ◽  
Normal Mucosa ◽  
Suppressor Gene ◽  
Survival Outcome ◽  
Prognostic Models

Abstract Background Neurotrophic tropomyosin receptor kinases (NTRKs) are a gene family function as oncogene or tumor suppressor gene in distinct cancers. We aimed to investigate the methylation and expression profiles and prognostic value of NTRKs gene in colorectal cancer (CRC). Methods An analysis of DNA methylation and expression profiles in CRC patients was performed to explore the critical methylations within NTRKs genes. The methylation marker was validated in a retrospectively collected cohort of 229 CRC patients and tested in other tumor types from TCGA. DNA methylation status was determined by quantitative methylation-specific PCR (QMSP). Results The profiles in six CRC cohorts showed that NTRKs gene promoter was more frequently methylated in CRC compared to normal mucosa, which was associated with suppressed gene expression. We identified a specific methylated region within NTRK3 promoter targeted by cg27034819 and cg11525479 that best predicted survival outcome in CRC. NTRK3 promoter methylation showed independently predictive value for survival outcome in the validation cohort (P = 0.004, HR 2.688, 95% CI [1.355, 5.333]). Based on this, a nomogram predicting survival outcome was developed with a C-index of 0.705. Furthermore, the addition of NTRK3 promoter methylation improved the performance of currently-used prognostic model (AIC: 516.49 vs 513.91; LR: 39.06 vs 43.64, P = 0.032). Finally, NTRK3 promoter methylation also predicted survival in other tumors, including pancreatic cancer, glioblastoma and stomach adenocarcinoma. Conclusions This study highlights the essential value of NTRK3 methylation in prognostic evaluation and the potential to improve current prognostic models in CRC and other tumors.

Tissue-specific transcription of the mouse alpha-fetoprotein gene promoter is dependent on HNF-1

1989 ◽  
Vol 9 (10) ◽  
pp. 4204-4212
Author(s):  
M H Feuerman ◽  
R Godbout ◽  
R S Ingram ◽  
S M Tilghman
Keyword(s):  
Specific Binding ◽  
Gene Promoter ◽  
Binding Activity ◽  
Alpha Fetoprotein ◽  
Transient Expression Assay ◽  
Band Shift ◽  
Specific Expression ◽  
Tissue Specific ◽  
Cis Acting ◽  
Dnase I Footprinting

Previous work identified four upstream cis-acting elements required for tissue-specific expression of the alpha-fetoprotein (AFP) gene: three distal enhancers and a promoter. To further define the role of the promoter in regulating AFP gene expression, segments of the region were tested for the ability to direct transcription of a reporter gene in transient expression assay. Experiments showed that the region within 250 base pairs of the start of transcription was sufficient to confer liver-specific transcription. DNase I footprinting and band shift assays indicated that the region between -130 and -100 was recognized by two factors, one of which was highly sequence specific and found only in hepatoma cells. Competition assays suggested that the liver-specific binding activity was HNF-1, previously identified by its binding to other liver-specific promoters. Mutation of the HNF-1 recognition site at -120 resulted in a significant reduction in transcription in transfection assays, suggesting a biological role for HNF-1 in the regulation of AFP expression.

Stage-differentiated modelling of DNA methylation landscapes uncovers salient biomarkers and prognostic signatures in colorectal cancer progression

2021 ◽  
Author(s):  
Sangeetha Muthamilselvan ◽  
Abirami Raghavendran ◽  
Ashok Palaniappan
Keyword(s):  
Colorectal Cancer ◽  
Dna Methylation ◽  
Cpg Island ◽  
Early Stage ◽  
P Value ◽  
Consensus Analysis ◽  
One Stage ◽  
Differentially Methylated Genes ◽  
Methylation Patterns ◽  
The Impact

Abstract Background: Aberrant DNA methylation acts epigenetically to skew the gene transcription rate up or down, with causative roles in the etiology of cancers. However research on the role of DNA methylation in driving the progression of cancers is limited. In this study, we have developed a comprehensive computational framework for the stage-differentiated modelling of DNA methylation landscapes in colorectal cancer (CRC), and unravelled significant stagewise signposts of CRC progression. Methods: The methylation β - matrix was derived from the public-domain TCGA data, converted into M-value matrix, annotated with AJCC stages, and analysed for stage-salient genes using multiple approaches involving stage-differentiated linear modelling of methylation patterns and/or expression patterns. Differentially methylated genes (DMGs) were identified using a contrast against controls (adjusted p-value <0.001 and |log fold-change of M-value| >2). These results were filtered using a series of all possible pairwise stage contrasts (p-value <0.05) to obtain stage-salient DMGs. These were then subjected to a consensus analysis, followed by Kaplan–Meier survival analysis to evaluate the impact of methylation patterns of consensus stage-salient biomarkers on disease prognosis.Results: We found significant genome-wide changes in methylation patterns in cancer cases relative to controls agnostic of stage. Our stage-differentiated analysis yielded the following stage-salient genes: one stage-I gene (FBN1), one stage-II gene (FOXG1), one stage-III gene (HCN1) and four stage-IV genes (NELL1, ZNF135, FAM123A, LAMA1). All the biomarkers were hypermethylated, indicating down-regulation and signifying a CpG island Methylator Phenotype (CIMP) manifestation. A significant prognostic signature consisting of FBN1 and FOXG1 survived all the steps of our analysis pipeline, and represents a novel early-stage biomarker. Conclusions: We have designed a workflow for stage-differentiated consensus analysis, and identified stage-salient diagnostic biomarkers and an early-stage prognostic biomarker panel. Our studies further yield a novel CIMP-like signature of potential clinical import underlying CRC progression.

scholarly journals Repeats as global DNA methylation marker in bovine preimplantation embryos

2017 ◽  
Vol 62 (No. 2) ◽  
pp. 43-50 ◽  
Author(s):  
W. Li ◽  
A. Van Soom ◽  
L. Peelman
Keyword(s):  
Dna Methylation ◽  
Mutation Rate ◽  
Methylation Level ◽  
Methylation Status ◽  
Repetitive Sequences ◽  
Cell Types ◽  
Blastocyst Stage ◽  
Repeat Sequence ◽  
Preimplantation Embryos ◽  
Global Dna Methylation

DNA methylation undergoes dynamic changes and is a crucial part of the epigenetic regulation during mammalian early development. To determine the DNA methylation levels in bovine embryos, we applied a bisulfite sequencing based method aimed at repetitive sequences including three retrotransposons (L1_BT, BovB, and ERV1-1-I_BT) and Satellite I. A more accurate estimate of the global DNA methylation level compared to previous methods using only one repeat sequence, like Alu, could be made by calculation of the weighted arithmetic mean of multiple repetitive sequences, considering the copy number of each repetitive sequence. Satellite I and L1_BT showed significant methylation reduction at the blastocyst stage, while BovB and ERV1-1-I_BT showed no difference. The mean methylation level of the repetitive sequences during preimplantation development was the lowest at the blastocyst stage. No methylation difference was found between embryos cultured in 5% and 20% O<sub>2</sub>. Because mutations of CpGs negatively influence the calculation accuracy, we checked the mutation rate of the sequenced CpG sites. Satellite I and L1_BT showed a relatively low mutation rate (1.92 and 3.72% respectively) while that of ERV1-1-I_BT and BovB was higher (11.95 and 24% respectively). Therefore we suggest using a combination of repeats with low mutation rate, taking into account the proportion of each sequence, as a relatively quick marker for the global DNA methylation status of preimplantation stages and possibly also for other cell types.

scholarly journals Intrahepatic cholangiocarcinomas with IDH1/2 mutation-associated hypermethylation at selective genes and their clinicopathological features

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyoungbun Lee ◽  
Young Seok Song ◽  
Yoonju Shin ◽  
Xianyu Wen ◽  
Younghoon Kim ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cpg Island ◽  
Methylation Status ◽  
Intraepithelial Neoplasia ◽  
Clinicopathological Features ◽  
Isocitrate Dehydrogenase 1 ◽  
Cancer Specific Survival ◽  
Mutation Status ◽  
Mucin Production ◽  
Small Duct

Abstract Intrahepatic cholangiocarcinoma (ICC) is a rare but fatal tumor. The isocitrate dehydrogenase 1 and 2 (IDH1/2) genes are known to be mutated in ICC. IDH1/2 mutations tend to be accompanied by enhanced hypermethylation at a subset of genomic loci. We sought to clarify the clinicopathological features, including prognostic value, of ICCs with IDH1/2 mutation-associated hypermethylation at a subset of genes. The mutation status of IDH1/2 and methylation status of 30 gene CpG island loci were analyzed in 172 cases of ICC using pyrosequencing and the MethyLight assay, respectively. The mutation status of IDH1/2 was correlated with clinicopathological features and the DNA methylation status at 30 gene loci. Then, the clinicopathological characteristics were analyzed regarding three-tiered methylation statuses in genes showing IDH1/2 mutation-associated methylation. IDH1/2 mutations were found in 9.3% of ICCs, and IDH1/2-mutated tumors were associated with the histological subtype, including the bile ductular type and small duct type, and poor differentiation. Eight DNA methylation markers showed associations with IDH1/2 mutations, and ICCs with > 5/8 methylated markers were associated with the bile ductular type or small duct type, absence of mucin production, absence of biliary intraepithelial neoplasia, and presence of chronic liver disease. > 5/8 methylated markers were an independent prognostic marker associated with better survival in both cancer-specific survival and recurrence-free survival. In summary, by analyzing the association between IDH1/2 mutations and DNA methylation in individual genes, we developed a panel of DNA methylation markers that were significantly associated with IDH1/2 mutations and were able to identify a subset of ICC with better clinical outcomes.

scholarly journals DNA Methylation of Endoglin Pathway Genes in Pregnant Women With and Without Preeclampsia

2020 ◽  
Vol 13 ◽  
pp. 251686572095968
Author(s):  
Allison H Rietze ◽  
Yvette P Conley ◽  
Dianxu Ren ◽  
Cindy M Anderson ◽  
James M Roberts ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Control Participant ◽  
Sample Collection ◽  
Promoter Regions ◽  
Participant Group

Objective: We compared blood-based DNA methylation levels of endoglin ( ENG) and transforming growth factor beta receptor 2 ( TGFβR2) gene promoter regions between women with clinically-overt preeclampsia and women with uncomplicated, normotensive pregnancies. Methods: We used EpiTect Methyl II PCR Assays to evaluate DNA methylation of CpG islands located in promoter regions of ENG (CpG Island 114642) and TGFβR2 (CpG Island 110111). Preeclampsia was diagnosed based on blood pressure, protein, and uric acid criteria. N = 21 nulliparous preeclampsia case participants were 1:1 frequency matched to N = 21 nulliparous normotensive control participants on gestational age at sample collection (±2 weeks), smoking status, and labor status at sample collection. Methylation values were compared between case and control participant groups [( ENG subset: n = 20 (9 cases, 11 controls); TGFβR2 subset: n = 28 (15 cases, 13 controls)]. Results: The majority of the preeclampsia cases delivered at ⩾34 weeks’ gestation (83%). Average methylation levels for ENG ([M ± (SD)]; Case Participant Group = 6.54% ± 4.57 versus Control Participant group = 4.81% ± 5.08; P = .102) and TGFβR2 (Case Participant Group = 1.50% ± 1.37 vs Control Participant Group = 1.70% ± 1.40; P = .695) promoter CpG islands did not differ significantly between the participant groups. Removal of 2 extreme outliers in the ENG analytic subset revealed a trend between levels of ENG methylation and pregnancy outcome (Case Participant Group = 5.17% ± 2.16 vs Control Participant Group = 3.36% ± 1.73; P = .062). Conclusion: Additional epigenetic studies that include larger sample sizes, investigate preeclampsia subtypes, and capture methylation status of CpG island shores and shelves are needed to further inform us of the potential role that ENG and TGFβR2 DNA methylation plays in preeclampsia pathophysiology.

scholarly journals Enhanced CXCR4 Expression Associates with Increased Gene Body 5-Hydroxymethylcytosine Modification but not Decreased Promoter Methylation in Colorectal Cancer

Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 539 ◽  
Author(s):  
Alexei J. Stuckel ◽  
Wei Zhang ◽  
Xu Zhang ◽  
Shuai Zeng ◽  
Urszula Dougherty ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Dna Methylation ◽  
Cell Lines ◽  
Promoter Methylation ◽  
Cpg Island ◽  
Methylation Status ◽  
Cxcr4 Expression ◽  
Normal Colonic Mucosa ◽  
Gene Body ◽  
Expression Levels

In colorectal cancer (CRC), upregulation of the C-X-C motif chemokine receptor 4 (CXCR4) is correlated with metastasis and poor prognosis, highlighting the need to further elucidate CXCR4’s regulation in CRC. For the first time, DNA methylation and 5-hydroxymethylcytosine aberrations were investigated to better understand the epigenetic regulation of CXCR4 in CRC. CXCR4 expression levels were measured using qPCR and immunoblotting in normal colon tissues, primary colon cancer tissues and CRC cell lines. Publicly available RNA-seq and methylation data from The Cancer Genome Atlas (TCGA) were extracted from tumors from CRC patients. The DNA methylation status spanning CXCR4 gene was evaluated using combined bisulfite restriction analysis (COBRA). The methylation status in the CXCR4 gene body was analyzed using previously performed nano-hmC-seal data from colon cancers and adjacent normal colonic mucosa. CXCR4 expression levels were significantly increased in tumor stromal cells and in tumor colonocytes, compared to matched cell types from adjacent normal-appearing mucosa. CXCR4 promoter methylation was detected in a minority of colorectal tumors in the TCGA. The CpG island of the CXCR4 promoter showed increased methylation in three of four CRC cell lines. CXCR4 protein expression differences were also notable between microsatellite stable (MSS) and microsatellite instable (MSI) tumor cell lines. While differential methylation was not detected in CXCR4, enrichment of 5-hydroxymethylcytosine (5hmC) in CXCR4 gene bodies in CRC was observed compared to adjacent mucosa.

Sign in / Sign up

Export Citation Format

Share Document