scholarly journals p38β - MAPK11 and its role in female cancers

2020 ◽  
Author(s):  
Periklis Katopodis ◽  
Rachel Kerslake ◽  
Athanasios Zikopoulos ◽  
Nefeli Eirini Beri ◽  
Vladimir Anikin
Keyword(s):  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Her2 Status ◽  
Tissue Specific ◽  
Cancer Data ◽  
Signalling Molecules ◽  
Significant Difference

Abstract Background The p38MAPK family of Mitogen Activated Protein Kinases are a group of signalling molecules involved in cell growth, survival, proliferation and differentiation. The widely studied p38α isoform is ubiquitously expressed and is implicated in a number of cancer pathologies, as are p38γ and p38δ. However, the mechanistic role of the isoform, p38β, remains fairly elusive. Recent studies suggest a possible role of p38β in both breast and endometrial cancer with research suggesting involvement in bone metastasis and cancer cell survival. Female tissue specific cancers such as breast, endometrial, uterine and ovary account for over 3,000,000 cancer related incidents annually; advancements in therapeutics and treatment however require a deeper understanding of the molecular aetiology associated with these diseases. This study provides an overview of the MAPK signalling molecule p38β (MAPK11) in female cancers using an in-silico approach. Methods A detailed gene expression and methylation analysis was performed using datasets from cBioportal, CanSar and MEXPRESS. Breast, Uterine Endometrial, Cervical, Ovarian and Uterine Carcinosarcoma TCGA cancer datasets were used and analysed.Results Data using cBioportal and CanSAR suggest that expression of p38β is lower in cancers: BRCA, UCEC, UCS, CESC and OV compared to normal tissue. Methylation data from SMART and MEXPRESS indicate significant probe level variation of CpG island methylation status of the gene MAPK11. Analysis of the genes’ two CpG islands shows that the gene was hypermethylated in the CpG1 with increased methylation seen in BRCA, CESC and UCEC cancer data sets with a slight increase of expression recorded in cancer samples. CpG2 exhibited hypomethylation with no significant difference between samples and high levels of expression. Further analysis from MEXPRESS revealed no significance between probe methylation and altered levels of expression. In addition, no difference in the expression of BRCA oestrogen/progesterone/HER2 status was seen. Conclusion This data provides an overview of the expression of p38β in female tissue specific cancers, showing a decrease in expression of the gene in BRCA, UCEC, CESC, UCS and OV, increasing the understanding of p38β MAPK expression and offering insight for future in-vitro investigation and therapeutic application.

scholarly journals p38β - MAPK11 and its role in female cancers

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Periklis Katopodis ◽  
Rachel Kerslake ◽  
Athanasios Zikopoulos ◽  
Nefeli Beri ◽  
Vladimir Anikin
Keyword(s):  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Her2 Status ◽  
Tissue Specific ◽  
Cancer Data ◽  
In Vitro Investigation ◽  
Significant Difference

Abstract Background The p38MAPK family of Mitogen Activated Protein Kinases are a group of signalling molecules involved in cell growth, survival, proliferation and differentiation. The widely studied p38α isoform is ubiquitously expressed and is implicated in a number of cancer pathologies, as are p38γ and p38δ. However, the mechanistic role of the isoform, p38β, remains fairly elusive. Recent studies suggest a possible role of p38β in both breast and endometrial cancer with research suggesting involvement in bone metastasis and cancer cell survival. Female tissue specific cancers such as breast, endometrial, uterine and ovary account for over 3,000,000 cancer related incidents annually; advancements in therapeutics and treatment however require a deeper understanding of the molecular aetiology associated with these diseases. This study provides an overview of the MAPK signalling molecule p38β (MAPK11) in female cancers using an in-silico approach. Methods A detailed gene expression and methylation analysis was performed using datasets from cBioportal, CanSar and MEXPRESS. Breast, Uterine Endometrial, Cervical, Ovarian and Uterine Carcinosarcoma TCGA cancer datasets were used and analysed. Results Data using cBioportal and CanSAR suggest that expression of p38β is lower in cancers: BRCA, UCEC, UCS, CESC and OV compared to normal tissue. Methylation data from SMART and MEXPRESS indicate significant probe level variation of CpG island methylation status of the gene MAPK11. Analysis of the genes’ two CpG islands shows that the gene was hypermethylated in the CpG1 with increased methylation seen in BRCA, CESC and UCEC cancer data sets with a slight increase of expression recorded in cancer samples. CpG2 exhibited hypomethylation with no significant difference between samples and high levels of expression. Further analysis from MEXPRESS revealed no significance between probe methylation and altered levels of expression. In addition, no difference in the expression of BRCA oestrogen/progesterone/HER2 status was seen. Conclusion This data provides an overview of the expression of p38β in female tissue specific cancers, showing a decrease in expression of the gene in BRCA, UCEC, CESC, UCS and OV, increasing the understanding of p38β MAPK expression and offering insight for future in-vitro investigation and therapeutic application.

Genome-Wide Epigenetic Analysis of Cancer Stem Cells (CSCs) In Acute Myeloid Leukemia.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3640-3640 ◽  
Author(s):  
Jumpei Yamazaki ◽  
Marcos R Estecio ◽  
Jaroslav Jelinek ◽  
David Graber ◽  
Yue Lu ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Stem Cells ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Cell Population ◽  
Progenitor Cell ◽  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Significant Difference

Abstract Abstract 3640 Background & Aims: The hypothesis that cancer is driven by Cancer Stem Cells (CSCs or Cancer-Initiating Cell) has recently attracted a great deal of attention. Epigenetic mechanism such as DNA methylation and histone modification play an important role in cancer cells and also in normal stem cells. However, their role remains unclear in CSCs. We sought to determine if CSCs have distinct epigenetic patterns in acute myeloid leukemia (AML). Methods: Peripheral blood samples in AML patients were separated to obtain stem cells (CD34+CD38-) and progenitor cells (CD34+CD38+) by magnetic cell sorting (MACS®, Myltenyi biotec). To study DNA methylation in CSCs in AML, we performed genome wide screening using methylated CpG island microarray (MCAM), which detects 7202 promoter CpG islands, 1348 non-promoter CpG islands, and 632 non-CpG island promoter methylation. MCAM was performed on 4 AML patient samples Next, we evaluated the methylation status of 7 genes which showed apparent higher DNA methylation in stem cells or progenitor cells in MCAM analysis, using a quantitative bisulfite-pyrosequencing for each population of stem cell, progenitor cell, and mature cells (CD34-) from peripheral blood samples in 6 AML patients. For histone modification analysis, we used Chromation immuprecipitation followed by massively parallel sequencing (ChIP-Seq) for stem cell and progenitor cell populations for H3K4me3 which is known to be a marker for activated genes. Results: By MCAM, we found minimal differences between stem cells and progenitor cells present in 2 out of 4 AML patients. Those few genes (<1%) which were shown to have higher DNA methylation in stem or progenitor cells by MCAM analysis were likely false positives, as no significant difference was found when analyzed by quantitative bisulfite-pyrosequencing. DNA methylation status for stem cell-related gene (OCT4, SOX2, MYC, HOXB4, and KLF4) also showed no significant difference. By ChIP-seq analysis, we found differences in 2362 genes between stem cells and progenitor cells. In stem cells, H3K4me3 was enriched in genes (Bmi1, Notch1, Wnt1, and etc) which are known to be important for stem cell function, but they were not enriched in the progenitor cell population. In pathway analysis of the H3K4me3 data, Hypoxia-Inducible Factor signaling, NFkB signaling, and p53 signaling are found to be enriched specifically in the stem cell population whereas Cellular Growth and Cell Cycle, and DNA Damage Response signaling are found in the progenitor cell population. Conclusions: There is no significant difference in DNA methylation between stem cell, progenitor cell or mature cell populations in AML. DNA methylation of promoter CpG islands is unlikely to explain tumor hierarchy in AML. Rather, histone modifications seem to have a greater significance in this regard. Disclosures: No relevant conflicts of interest to declare.

scholarly journals WASF2 Overexpression and Promoter Hypomethylation Are Associated With Poor Clinical Outcomes in Hepatocellular Carcinoma

2021 ◽  
Author(s):  
Hye Ri Ahn ◽  
Geum Ok Baek ◽  
Moon Gyeong Yoon ◽  
Ju A Son ◽  
Jung Hwan Yoon ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Regulatory Mechanism ◽  
Cpg Island ◽  
Methylation Status ◽  
Migration And Invasion ◽  
Mesenchymal Transition ◽  
Hcc Cells

Abstract Background: Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers worldwide. Wiskott-Aldrich syndrome protein family member 2 (WASF2) is an integral member of the actin cytoskeleton pathway that plays a crucial role in cell motility. In this study, we aimed to explore the role of WASF2 in HCC carcinogenesis and its regulatory mechanism. Methods: WASF2 expression in HCC was analyzed using six public RNA-seq datasets and 66 paired tissues from patients with HCC. Role of WASF2 in HCC cell phenotypes was evaluated using small interfering RNA (siRNA) in vitro and in vivo. Epigenetic regulatory mechanism of WASF2 was assessed in the Cancer Genome Atlas liver hepatocellular carcinoma project (TCGA_LIHC) dataset and also validated in 38 paired HCC tissues. Results: WASF2 is overexpressed in HCC and is clinically correlated with prognosis. WASF2 inactivation decreased the viability, growth, proliferation, migration, and invasion of Huh-7 and SNU475 HCC cells by restoring G2/M checkpoint function, inducing cell death, and inhibiting epithelial-mesenchymal transition, and hindering actin polymerization. In addition, WASF2 knockdown using siWASF2 in a xenograft mouse model exerted tumor suppressive effect. Furthermore, we observed a negative correlation between WASF2 methylation status and mRNA expression. The cg24162579 CpG island in the WASF2 5′ promoter region was hypomethylated in HCC compared to matched non-tumor samples. Patients with high WASF2 methylation and low WASF2 expression displayed the highest overall survival.Conclusions: WASF2 is overexpressed and hypomethylated in HCC and correlates with patient prognosis. Moreover, WASF2 inactivation exerts anti-tumorigenic effects on HCC cells in vitro and in vivo, suggesting that WASF2 could be a potential therapeutic target for HCC.

scholarly journals Molecular Genetics of Esophageal Cancer : Indian Perspective

2021 ◽  
Vol 6 (2) ◽  
pp. 155-160
Author(s):  
Suddhasattwa Ray ◽  
Mona Malekzadehmoghani ◽  
Sonia S Ray ◽  
Partha Sen ◽  
Sayan Chakraborty
Keyword(s):  
Promoter Methylation ◽  
Methylation Status ◽  
Cpg Islands ◽  
Stage Iv ◽  
Tissue Samples ◽  
Cpg Dinucleotides ◽  
Specific Pcr ◽  
Significant Difference ◽  
Indian Perspective

Background: RIZ1 is one of the tumor-suppressor genes that is silenced in many human cancers. Change in RIZ1 expression has not been reported in ESCC patients. Therefore, the aim of this study was to investigate the role of RIZ1 in ESCC in the Indian population. Methods: Twelve esophageal squamous-cell carcinoma (ESCC) patients in stage IV and 12 healthy individuals were used in this study. Tissue sampling was taken from individuals and total RNA was isolated and then cDNA was synthesized using PCR. RIZ1 primers were then designed, and RIZ1 expression was quantified by qRT-PCR. Mapping of CpG islands in RIZ1 promoter was performed using bioinformatics tools. The promoter methylation status of this gene was studied using u methylation-specific PCR (MSP). T-student test was used to analyze the data.Results: Decreased RIZ1 expression was observed in ESCC compared with healthy controls. The results showed a relatively higher density of CpG dinucleotides in the RIZ1 promoter. No significant difference in promoter methylation was observed in blood and tissue samples.Conclusion: The study showed a significant down-regulation of RIZ-1 gene in the blood and tissue samples of ESCC patients that did not related to the altered promoter methylation.

Epigenetic inactivation to target the arginine biosynthetic pathway in multiple myeloma.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e18567-e18567
Author(s):  
Eleftheria Hatzimichael ◽  
Aggeliki Dasoula ◽  
Nelofer Syed ◽  
Peter Wojciech Szlosarek ◽  
George Dranitsaris ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Disease ◽  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Control Group ◽  
Arginine Biosynthesis ◽  
Extramedullary Disease ◽  
Arginine Deprivation ◽  
Significant Difference

e18567 Background: Argininoosuccinate synthetase-1 (ASS1) catalyses the rate-limiting step in arginine biosynthesis, the conversion of citruline to arginine. Argininosuccinate lyase (ASL) is an enzyme that catalyses the reversible breakdown of arginosuccinate producing arginine and fumerate. Arginine deprivation using arginine deiminase (ADI-PEG20) is currently considered as a novel therapeutic intervention for cancer. In this perspective, we investigated the methylation status of the ASS1 and ASL CpG islands in multiple myeloma (MM) and analyzed for clinical relevance. Methods: Genomic DNA was extracted from bone marrow aspirate samples from 46 MM patients (28 male, 18 female, median age 64 years) obtained at diagnosis. Methylation-specific PCR was employed to study the methylation in the ASS1 and ASL CpG islands. DNA was isolated and bisulphite modified using commercially available kits. Logistic regression analyses were used to measure the association between gene methylation and sex, age>65, ISS stage, presence of extramedullary disease, renal failure and bone disease. Kaplan-Meier curves were used to estimate the probabilities of survival and the Log-rank test to assess the statistical significance of differences in event rates. Results: Methylation in the CpG island of ASS1 was detected in 71.7% patients and of ASL in 37% patients, while simultaneous methylation in both genes was present in 10 patients. None of the two genes was detectably methylated in the control group. Patients with ASS1 methylation were less likely to have bone disease (p=0.04, OR=0.22) and extramedullary disease (p=0.05, OR=0.22) and a trend was also noted that these patients were less likely to be >65 years of age (p=0.2, OR=0.37). We did not detect any statistically significant difference in overall survival by methylation status of the studied genes in this small study size. Conclusions: We demonstrate for the first time that arginine biosynthesis genes ASS1 and ASL are methylated in MM.Methylation of ASS1 was found to be more frequent and negatively associated with bone or extramedullary disease. Further evaluation of ASS1 and ASL is warranted in MM and supports the expansion of arginine deprivation trials in these patients

An Upstream Insulator Element Regulates DLK1 Imprinting in AML

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 202-202
Author(s):  
Haytham Khoury ◽  
Fernando Suarez-Saiz ◽  
Samantha Wu ◽  
Serban San-Marina ◽  
Mark Minden
Keyword(s):  
Cell Line ◽  
Binding Sites ◽  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Ctcf Binding ◽  
Monoallelic Expression ◽  
Methylation Analysis ◽  
Insulator Element ◽  
Significant Difference

Abstract DLK1 is a transmembrane protein of the epidermal growth factor (EGF) family, encoded by a paternally-imprinted gene located within the chromosomal region 14q32. In addition to DLK1, this region contains other paternally expressed genes, including Dio3 and RTl1 and a set of genes expressed from the maternal chromosome, including MEG3, C/D snoRNA and Mirg. In mice, the expression of these paternally- and maternally-imprinted genes is inversely correlated and controlled by the methylation status intergenic differentially methylated region (IG-DMR). Recently it has been reported that DLK1 is expressed at higher than normal levels in myelodysplasia (MDS) and also in acute myeloblastic leukemia (AML). To determine whether loss of imprinting (LOI) could account for DLK1 overexpression and to study the mechanisms that regulate DLK1 imprinting in AML, we analyzed the expression of 3 informative coding SNPs located in exon 5 (rs#1802710, rs#2295660, rs#1058009) in 11 normal bone marrows (NBMs), the 3 cell lines (OCI/AML-5, NB4 and K562) characterized by DLK1 upregulation and 40 AML patients (pts) with DLK1 overexpression. Furthermore, we undertook quantitative methylation analysis, using the MassARRAY system, of 7 CpG rich-reas: 3 located upstream or within MEG3 and correspond to the CpG islands # 30, 45 and 70, 1 corresponds to the putative IG-DMR, and 3 located upstream or within DLK1 and correspond to the CpG islands # 26, 65 and 79. Informative SNPs were found in 6 NBMs, 28 AML pts and the cell line K562. Of these, biallelic DLK1 expression was found in the cell line K562 as well as 22/28 (72%) AML pts. In contrast, all NBMs and 7 AML pts were found to have monoallelic expression. Pts with biallelic DLK1 expression showed higher DLK1/GAPDH than pts with monoallelic expression (median: 0.0057 vs 0.0024). On the other hand, no significant difference in MEG3 levels was found between the two groups (P = 0.49) and no correlation was found between DLK1 and MEG3 levels (r= −0.1212). The quantitative methylation analysis revealed no difference between the pts with monoallelic and biallelic DLK1 expression in the methylation patterns of the CpG islands # 30, 45, 70, 65 and 26 or the IG-DMR. In contrast, significant difference was found in the methylation the CpG island #79, located 18 kb upstream DLK1 (P &lt;0.0001). In fact, there was a strong association between bi-allelic DLK1 expression and the hypermethylation of the latter CpG island, suggesting that this region contains an insulator element that regulates DLK1 imprinting and transcription through a methylation-sensitive mechanisms. Almost all insulator elements use the zinc finger protein CTCF to achieve their silencing activity. Indeed, a bioinformatic search indicated the presence of at least 4 predicted CTCF-binding sites. The CpG dinucleotides located within or in the vicinity of these binding sites were largely hypermethylated in AML with biallelic DLK1 expression, in sharp contrast with NBMs and pts with monoallelic DLK1 expression. Chromatin immunoprecipitation analysis confirmed that the CTCF protein binds to this region in 1 NBM and 2 pts with monoallelic expression, whereas no immunoprecipitation was seen in the K562 and 2 pts with biallelic DLK1 expression. Taken together, our data suggest DLK1 LOI occurs in 72% of AML and the expression of the paternally-imprinted DLK1 and the maternally-imprinted MEG3 genes are not coordinated in AML. Furthermore, an insulator element located 18 kb upstream DLK1 plays important role in controlling this gene imprinting in AML, through interaction with CTCF.

scholarly journals Association study of polymorphisms within inflammatory genes and methylation status in treatment response in major depression

2019 ◽  
Vol 60 ◽  
pp. 7-13 ◽  
Author(s):  
Metodi Draganov ◽  
María Jesús Arranz ◽  
Juliana Salazar ◽  
Javier de Diego-Adeliño ◽  
Cristina Gallego-Fabrega ◽  
...  
Keyword(s):  
Major Depression ◽  
Treatment Response ◽  
Cpg Island ◽  
Antidepressant Treatment ◽  
Methylation Status ◽  
Cpg Islands ◽  
Inflammatory Genes ◽  
Allelic Distribution ◽  
And Gender

AbstractBackground:Although pharmacogenetics for major depressive disorder (MDD) is gaining momentum, the role of genetics in differences in response to antidepressant treatment is controversial, as they depend on multifactorial and polygenic phenotypes. Previous studies focused on the genes of the serotonergic system, leaving apart other pathological factors such as the inflammatory pathway. The main objective of the study was to assess whether treatment response might be associated with specific inflammation-related genetic variants or their methylation status.Methods:41 SNPs in 8 inflammatory genes: interleukin (IL) 1-β, IL2, IL6, IL6R, IL10, IL18, tumor necrosis factor (TNF)-α and interferon (IFN)-γ were genotyped in 153 patients with MDD, who were evaluated with the Mausdley Staging Method to determine treatment response profiles. Pyrosequencing reactions and methylation quantification were performed in a PyroMark Q24 in 5 selected CpG islands of IL1- β, IL6 and IL6R. Linear and logistic regression analyses were conducted, including age and gender as covariates using PLINK 1.07.Results:Allelic distribution of IL1- β rs1143643 was significantly associated with MSM scores (FDR corrected p = 0.04). Allelic distribution of IL6R rs57569414 showed a trend towards significance with MSM scores (p = 0.002; FDR corrected p = 0.07). Haplotype analyses showed associations between allelic combinations of IL1-β and IL10 with treatment response (FDR corrected p < 0.01). Methylation percentage of treatment responders was only higher in an IL6R CpG island (p < 0.05).Conclusions:These exploratory findings suggest that IL1-β and, marginally, IL6R polymorphisms may affect treatment response in major depression. If confirmed, these results may account for the heterogeneous phenotypes of major depression that underlie differences in treatment response.

scholarly journals Dose dependence of efficacy but not of safety in sublingual immunotherapy

2016 ◽  
Vol 65 (1) ◽  
Author(s):  
F. Frati ◽  
C. Incorvaia ◽  
F. Marcucci ◽  
L. Sensi ◽  
G. Di Cara ◽  
...  
Keyword(s):  
Sublingual Immunotherapy ◽  
Clinical Symptoms ◽  
Meta Analysis ◽  
Dose Dependence ◽  
Subcutaneous Immunotherapy ◽  
High Dose ◽  
Systemic Reactions ◽  
Significant Difference

Sublingual immunotherapy (SLIT) currently represents, as indicated by meta-analysis of its efficacy and safety, a valid option to the generally used traditional subcutaneous immunotherapy (SCIT) for treating respiratory allergy. Regarding efficacy, recent studies demonstrated that, similar to what has already been observed in SCIT as well as in experimental and clinical studies about the magnitudo of allergen exposure, the effectiveness on both clinical symptoms and immunologic changes depends on the amount of allergen administered during treatment. In addition, in vitro studies addressed with the role of dendritic cells, currently considered to be of pivotal importance in orienting toward tolerance the immune response to allergens, showed that the internalisation of allergen molecules, which is followed by tolerogenic presentation to T cells, depends on the amount of allergen. However, such dose dependence is not apparent concerning the safety. In fact, the comparison of studies respectively conducted with high and low allergen doses did not show differences in the rate of systemic reactions, which in any case never had the presentation of anaphylaxis, and instead a significant difference in the rate of local reactions, following the oral and gastrointestinal contact with the allergen extract, in favour of high dose studies.

scholarly journals Hypermethylation of DHRS3 as a Novel Tumor Suppressor Involved in Tumor Growth and Prognosis in Gastric Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Sha Sumei ◽  
Kong Xiangyun ◽  
Chen Fenrong ◽  
Sun Xueguang ◽  
Hu Sijun ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Tumor Suppressor ◽  
Tumor Growth ◽  
Human Cancer ◽  
Methylation Status ◽  
Ectopic Expression ◽  
Survival Times

Background/AimsThe role of DHRS3 in human cancer remains unclear. Our study explored the role of DHRS3 in gastric cancer (GC) and its clinicopathological significance and associated mechanisms.MaterialsBisulfite-assisted genomic sequencing PCR and a Mass-Array system were used to evaluate and quantify the methylation levels of the promoter. The expression levels and biological function of DHRS3 was examined by both in vitro and in vivo assays. A two-way hierarchical cluster analysis was used to classify the methylation profiles, and the correlation between the methylation status of the DHRS3 promoter and the clinicopathological characteristics of GC were then assessed.ResultsThe DHRS3 promoter was hypermethylated in GC samples, while the mRNA and protein levels of DHRS3 were significantly downregulated. Ectopic expression of DHRS3 in GC cells inhibited cell proliferation and migration in vitro, decreased tumor growth in vivo. DHRS3 methylation was correlated with histological type and poor differentiation of tumors. GC patients with high degrees of CpG 9.10 methylation had shorter survival times than those with lower methylation.ConclusionDHRS3 was hypermethylated and downregulated in GC patients. Reduced expression of DHRS3 is implicated in gastric carcinogenesis, which suggests DHRS3 is a tumor suppressor.

scholarly journals Demethylation of somatic and testis-specific histone H2A and H2B genes in F9 embryonal carcinoma cells

1993 ◽  
Vol 13 (9) ◽  
pp. 5538-5548
Author(s):  
Y C Choi ◽  
C B Chae
Keyword(s):  
Embryonal Carcinoma ◽  
Cpg Island ◽  
Cpg Islands ◽  
High Density ◽  
Carcinoma Cells ◽  
Embryonal Carcinoma Cells ◽  
Cpg Dinucleotides ◽  
F9 Embryonal Carcinoma Cells ◽  
Methylation Patterns

In contrast to many other genes containing a CpG island, the testis-specific H2B (TH2B) histone gene exhibits tissue-specific methylation patterns in correlation with gene activity. Characterization of the methylation patterns within a 20-kb segment containing the TH2A and TH2B genes in comparison with that in a somatic histone cluster revealed that: (i) the germ cell-specific unmethylated domain of the TH2A and TH2B genes is defined as a small region surrounding the CpG islands of the TH2A and TH2B genes and (ii) somatic histone genes are unmethylated in both liver and germ cells, like other genes containing CpG islands, whereas flanking sequences are methylated. Transfection of in vitro-methylated TH2B, somatic H2B, and mouse metallothionein I constructs into F9 embryonal carcinoma cells revealed that the CpG islands of the TH2A and TH2B genes were demethylated like those of the somatic H2A and H2B genes and the metallothionein I gene. The demethylation of those CpG islands became significantly inefficient at a high number of integrated copies and a high density of methylated CpG dinucleotides. In contrast, three sites in the somatic histone cluster, of which two sites are located in the long terminal repeat of an endogenous retrovirus-like sequence, were efficiently demethylated even at a high copy number and a high density of methylated CpG dinucleotides. These results suggest two possible mechanisms for demethylation in F9 cells and methylation of CpG islands of the TH2A and TH2B genes at the postblastula stage during embryogenesis.

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