scholarly journals Dynamic Changes of DNA Methylation During Wild Strawberry (Fragaria nilgerrensis) Tissue Culture

2021 ◽  
Vol 12 ◽  
Author(s):  
Qiang Cao ◽  
Yuxi Feng ◽  
Xiongwei Dai ◽  
Lin Huang ◽  
Jiamin Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Tissue Culture ◽  
Plant Tissue ◽  
Crop Improvement ◽  
Functional Enrichment ◽  
Global Methylation ◽  
Asexual Propagation ◽  
Culture Process ◽  
Wild Strawberry

Tissue culture is an important tool for asexual propagation and genetic transformation of strawberry plants. In plant tissue culture, variation of DNA methylation is a potential source of phenotypic variation in regenerated plants. However, the genome wide dynamic methylation patterns of strawberry tissue culture remain unclear. In this study, we used whole-genome bisulfite sequencing (WGBS) to study genomic DNA methylation changes of a wild strawberry Fragaria nilgerrensis at six stages: from explants of shoot tips to outplanting and acclimation. Global methylation levels showed that CG sites exhibited the highest methylation level in all stages with an average of 49.5%, followed by CHG (33.2%) and CHH (12.4%). Although CHH accounted for the lowest proportion of total cytosine methylation, it showed the most obvious methylation change and the most of these changes occurred in the transposable element regions. The overall methylation levels alternately decreased and increased during the entire tissue culture process and the distribution of DNA methylation was non-uniform among different genetic regions. Furthermore, much more differentially methylated regions (DMRs) were detected in dedifferentiation and redifferentiation stages and most of them were transposable elements, suggesting these processes involved activating or silencing of amounts of transposons. The functional enrichment of the DMR-related genes indicated that genes involved in hormone metabolic processes, plant development and the stress response changed methylation throughout the tissue culture process. Finally, the quantitative real-time PCR (qRT-PCR) was conducted to examine the association of methylation and gene expression of a set of different methylated genes. Our findings give deeper insight into the epigenetic regulation of gene expression during the plant tissue cultures process, which will be useful in the efficient control of somaclonal variations and in crop improvement.

Abstract 500: DNA Methylation Profiling Reveals an Epithelial/Endothelial-Mesenchymal Transition-like Signature of Intima-Media Cells in the Ascending Aorta of Bicuspid Aortic Valve Patients

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Hanna M Björck ◽  
Lei Du ◽  
Valentina Paloschi ◽  
Shohreh Maleki ◽  
Silvia Pulignani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Epithelial Mesenchymal Transition ◽  
Ascending Aorta ◽  
Molecular Signature ◽  
Aortic Valves ◽  
Global Methylation ◽  
Mesenchymal Transition ◽  
Differentially Methylated Genes ◽  
Increased Risk

Introduction: Individuals with bicuspid aortic valves (BAV) are at increased risk of ascending aortic aneurysm than individuals with tricuspid aortic valves (TAV), but the underlying mechanism is not fully understood. Aberrant DNA methylation has been described in various human diseases, and we have shown that key enzymes in the methylation machinery are differentially expressed in the aortic intima-media of BAV and TAV patients. In the present study, we assessed the hypothesis that DNA methylation may play an important role during aneurysm formation in BAV. We undertook a global methylation approach to delineate biological processes associated with BAV aortopathy, using TAV as a reference. Methods: Ascending aortic biopsies were collected from 21 BAV and 24 TAV patients, with either a non-dilated or a dilated aorta, at the time of surgery. Global DNA methylation was measured in the intima-media layer using Illumina 450k Array. Gene expression was analyzed in the same samples using Affymetrix Exon Array. Results: Compared with TAV, the BAV dilated aorta was hypomethylated (P=0.031), correlating with an up-regulation of global gene expression. A total of 4913 differentially methylated regions (DMRs) were identified and Hallmark analysis of the DMR-associated genes with a fold change of 10% (n=3147) showed a gene signature of Epithelial Mesenchymal Transition (EMT) (FDR q=2.91e-29). This was further confirmed by functional annotation analysis of hypomethylated DMRs using the Genomic Regions Enrichment of Annotations Tool (Stanford University), showing association to actin filament bundle (P=7.09e-12), stress fibers (P=1.72e-11) and adherence junctions (P=2.97e-8). Interestingly, analysis of non-dilated BAV and TAV aorta revealed that genes involved in EMT were the most differentially methylated genes prior to dilatation (FDR q=1.18e-6). We further confirmed the EMT-related molecular signature by immunostaining of some key players of EMT. In conclusion, epigenetic profiling clearly revealed differential methylation between BAV and TAV aorta, particularly in EMT-related genes. Aberrant EMT in the ascending aorta prior to dilatation may constitute the basis for the increased aneurysm susceptibility in BAV patients.

152 SPECIES-SPECIFIC DIFFERENCES IN THE METHYLATION REPROGRAMMING DURING EARLY PRE-IMPLANTATION DEVELOPMENT

2017 ◽  
Vol 29 (1) ◽  
pp. 184
Author(s):  
S. Canovas ◽  
E. Ivanova ◽  
S. Garcia-Martinez ◽  
R. Romar ◽  
N. Fonseca-Balvis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Expression Profiles ◽  
Differential Expression Analysis ◽  
Gene Expression Pattern ◽  
Reproductive Technologies ◽  
Global Methylation ◽  
Species Specific

Studies in mouse and human have shown extensive DNA methylation reprogramming in pre-implantation development followed by remethylation from implantation. However, the extent to which such reprogramming is conserved in mammals and the timing of demethylation and remethylation are unknown. As part of a major objective to characterise methylation dynamics in the bovine and porcine species from the oocyte to the blastocyst stage, we aimed here to compare the distribution of methylation at single-base resolution in both species at Day 7.5 of development. The DNA methylation profiles were obtained from individual blastocysts at Day 7.5 [pig: 3 in vivo, 3 in vitro; cow: 3 in vivo, 3 in vitro, 3 inner cell mass (ICM) and 3 trophoectoderm (TE) dissected from in vitro blastocysts] using the post-bisulphite adaptor tagging method and Illumina sequencing. For oocytes, data (GEO: GSE63330) from Schroeder et al. 2015 were analysed. Raw sequences were mapped, methylation calls made using Bismark and data analysis and visualisation was done within the SeqMonk platform. Gene expression profiles from individual blastocysts (3 pig, 3 cow) were obtained by RNA-seq. Annotated mRNA features were quantitated in SeqMonk and these were fed into DESeq2 for differential expression analysis (P < 0.05) as previously reported (Love et al. 2014 Genome Biol. 15, 550). Global methylation levels in whole blastocysts differed substantially between porcine and bovine embryos (in vivo: 12.33 ± 3.6 v. 28.33 ± 3.5%; in vitro: 15.02 ± 3.3 v. 24.41 ± 4.1%). In addition, the distribution of methylation differed: the pattern of cytosine methylated seemed random in the porcine genome, but was highly structured in the bovine genome, with methylation predominantly over gene bodies, resembling the profile previously reported in oocytes (Schroeder et al. 2015 PLoS Genet. 11, e1005442). Regarding correlation analysis, gene expression versus methylation were plotted. It suggested that gene body methylation reflected gene expression pattern in oocytes as well as in bovine blastocysts. Pair-wise comparison of isolated ICM and TE was filtered to require 5% change, and replicate set statistics were applied. This revealed very similar total and regional methylation levels in the 2 compartments, indicating that remethylation does not initiate preferentially in one compartment in bovine pre-implantation embryos. This confirms, from a viewpoint of the genome-wide DNA methylation, what has been observed in mouse for specific genes: the trophoblast-specific DNA methylation occurs after the segregation of the TE and ICM (Nakanishi et al. 2012 Epigenetics 7, 173–183). Our study is the first to provide whole genome methylation profiles from single blastocysts of economically important livestock species. Our data demonstrate that methylation reprogramming in early pre-implantation development is species specific. Knowledge of these specific patterns may have high importance when decisions are taken regarding the use of assisted reproductive technologies, cloning, or generation of transgenic animals. This work was funded by AGL2015–66341-R (MINECO-FEDER), PRX14/00348 (MECD), 19595/EE/14 (F. Séneca).

Global Epigenomic Profiling Demonstrates That Myelodysplasia Is Characterized by a Distinct Epigenetic Signature with Aberrant DNA Methylation Changes Involving Various Malignant and Hematopoietic Pathways.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2436-2436
Author(s):  
L. Zhou ◽  
J. Opalinska ◽  
D. Sohal ◽  
R. Thompson ◽  
Y. Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Expression Analysis ◽  
Peripheral Blood ◽  
Gene Expression Analysis ◽  
Whole Genome ◽  
Gene Promoters ◽  
Global Methylation ◽  
Peripheral Blood Leucocyte ◽  
Peripheral Blood Leucocytes

Abstract Myelodysplasia (MDS) is a clonal hematopoietic disorder that leads to ineffective hematopoiesis and peripheral cytopenias. DNMT inhibitors such as azacytidine have led to clinical responses in patients, though the genes affected by epigenetic alterations are not well known. Whole genome DNA methylation was analyzed by a recently described novel method, The HELP assay (HpaII tiny fragment Enrichment by Ligation-mediated PCR; Khulan et al, Genome Res. 2006 Aug;16(8)) that uses differential methylation specific restriction digestion by HpaII and MspI followed by amplification, two color labeling and cohybridization to quantitatively determine individual promoter island methylation. A whole genome human promoter array (Nimblegen) was used to determine the level of methylation of 25626 gene promoters by calculating HpaII/MspI cut fragment intensity ratio. Peripheral blood leucocytes from 13 patients with MDS were compared to 9 age matched normal and anemic controls. Gene expression analysis was performed using 37K oligo maskless arrays on cDNA obtained from the same samples. Analysis showed that whole genome methylation profiling has greater discriminatory power in separating clusters of MDS samples from normal and anemic controls when compared to gene expression analysis. Unsupervised clustering based on epigenetic profiling demonstrated that only two cases of early MDS clustered with normals as compared to absolutely no separation between MDS and normals with clustering based on gene expression patterns. A high correlation (r=0.88–0.96) was observed between global methylation profiles of matched sets of bone marrow and peripheral blood leucocyte samples from selected patients demonstrating that peripheral blood leucocytes can be a valid surrogate for epigenomic analysis. Further analysis showed that genes consistently aberrantly methylated in MDS included Syk kinase, HOXB3, several histone acetyltranferases and others. Functional analysis by Ingenuity showed that cancer and cell signaling pathways were the most affected by epigenetic silencing. Most interestingly, a large proportion of gene promoters were also aberrantly hypomethylated. These included genes from Ras oncogene family, the CDC42 GTPase, various methyl binding proteins and other proteins mainly encoding for cancer and hematopoiesis functional pathways, thus biologically validating our analysis. Therefore, our data demonstrates that MDS is characterized by distinct epigenetic aberrations that are preserved in peripheral blood leucocytes. These can be the basis of future studies on pathogenesis and diagnosis for this disease and can potentially uncover a new set of therapeutic gene targets.

Global and HOX Gene DNA Methylation In Normal Karyotype Acute Myeloid Leukemia: Clinical Implications and Molecular Correlations

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 231-231
Author(s):  
Stefan Deneberg ◽  
Andreas Lennartsson ◽  
Bertil Uggla ◽  
Verena Gaidzik ◽  
Andrea Corbacioglu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Bone Marrow ◽  
Hox Genes ◽  
Normal Karyotype ◽  
Global Methylation ◽  
Hox Gene ◽  
Mutational Status ◽  
Average Methylation ◽  
Wbc Count

Abstract Abstract 231 Background: DNA methylation induces gene silencing in a nonrandom fashion in many types of malignancies. In AML there is no consensus regarding the clinical implications of DNA methylation on a global level. Normal karyotype AML (NK AML) can be prognostically stratified by molecular mutations in genes such as FLT3 and NPM1. We have previously reported that increased gene promoter methylation levels may have positive prognostic implications in AML. Now we have focused and expanded our analysis in a homogenous group of NK AML in an effort to illuminate these issues. Methods and patients: We analyzed genome wide DNA methylation signatures from the diagnostic bone marrow samples of 58 de novo NK AML with the IlluminaHuman27 Methylation array, covering 27000 CpG sites, mainly located in the promoter regions of 15000 individual genes. Global methylation was defined as the average methylation values of all measured CpG sites in the specific sample. All patients were between 18 and 67 years of age and received standard induction chemotherapy. All were eligible for intensive consolidation therapy including allogeneic transplantation. FACS sorted normal bone marrow separated into four stages of myeloid differentiation were analyzed as normal controls. Methylation data were correlated to clinical outcomes and molecular mutational status of NPM1 and FLT3. Functional annotation analyses were performed on differentially methylated genes to find epigenetically perturbed pathways. Further molecular analysis of CEBPA, IDH1 and IDH2 is currently performed. Results and discussion: Global methylation levels varied substantially between AML samples but remained mainly unchanged during normal myeloid differentiation. Methylation levels were significantly higher in AML cases than in the normal myeloid progenitors (p<0.001). There were no correlations between methylation levels, age, white blood cell (WBC) count or bone marrow blast percentage at diagnosis. Increased global methylation correlated significantly to increased in vivo chemosensitivity and to patient survival. CR rates after one course of induction chemotherapy were 64% in the quartile of patients with the highest level of global DNA methylation compared to 32% in others (HR 3.9, p=0.04). Median overall survival of patients of the most methylated quartile was not reached and significantly longer than the 16 months median survival of the least methylated quartile (p=0.001) (see figure below). In a Cox Regression model stratified for FLT3-mutational status, methylation level was an independent prognostic factor for survival (p=0.01) together with WBC count (p=0.01). A functional annotation analysis revealed that NPM1 wild type samples had an enrichment of Homeobox (HOX) gene methylation as compared to NPM1 mutated cases (p=1.7×10−11), providing a mechanism for the previously described difference in HOX gene expression in NPM1 wt vs. NPM1 mutated AML. The average methylation levels of all HOX genes were higher in wild type NPM1 cases compared to NPM1 mutated cases (p=0.02). Additional gene expression array data in our cohort of patients also showed methylation levels of individual HOX genes to be correlated inversely with expression. HOX genes were also enriched in non-FLT3ITD cases compared to FLT3ITD-cases, however, not to a statistically significant degree. In conclusion we show that global DNA methylation levels are predictive of response to chemotherapy and an independent prognostic factor for survival in normal karyotype AML. Furthermore, our results suggest that HOX gene methylation may be the mechanism underlying the previously known difference in HOX-gene expression between NPM1 mutated and unmutated AML cases. Disclosures: Nahi: Jansen-Cilag: Honoraria; Celgene: Honoraria.

scholarly journals Molecular Analyses of Soma-clonal Variation in Date Palm and Banana for Early Identification and Control of Off-types Generation

2010 ◽  
Author(s):  
Yuval Cohen ◽  
Christopher A. Cullis ◽  
Uri Lavi
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Tissue Culture ◽  
Oil Palm ◽  
Early Identification ◽  
Date Palm ◽  
Differentially Expressed ◽  
Date Palms ◽  
Fruit Setting ◽  
Methylation Patterns

Date palm (Phoenix dactylifera L.) is the major fruit tree grown in arid areas in the Middle East and North Africa. In the last century, dates were introduced to new regions including the USA. Date palms are traditionally propagated through offshoots. Expansion of modern date palm groves led to the development of Tissue Culture propagation methods that generate a large number of homogenous plants, have no seasonal effect on plant source and provide tools to fight the expansion of date pests and diseases. The disadvantage of this procedure is the occurrence of off-type trees which differ from the original cultivar. In the present project we focused on two of the most common date palm off-types: (1) trees with reduced fruit setting, in which most of the flowers turn into three-carpel parthenocarpic fruits. In a severe form, multi-carpel flowers and fruitlets (with up to six or eight carpels instead of the normal three-carpel flowers) are also formed. (2) dwarf trees, having fewer and shorter leaves, very short trunk and are not bearing fruits at their expected age, compared to the normal trees. Similar off-types occur in other crop species propagated by tissue culture, like banana (mainly dwarf plants) or oil palm (with a common 'Mantled' phenotype with reduced fruit setting and occurrence of supernumerary carpels). Some off-types can only be detected several years after planting in the fields. Therefore, efficient methods for prevention of the generation of off-types, as well as methods for their detection and early removal, are required for date palms, as well as for other tissue culture propagated crops. This research is aimed at the understanding of the mechanisms by which off-types are generated, and developing markers for their early identification. Several molecular and genomic approaches were applied. Using Methylation Sensitive AFLP and bisulfite sequencing, we detected changes in DNA methylation patterns occurring in off-types. We isolated and compared the sequence and expression of candidate genes, genes related to vegetative growth and dwarfism and genes related to flower development. While no sequence variation were detected, changes in gene expression, associated with the severity of the "fruit set" phenotype were detected in two genes - PdDEF (Ortholog of rice SPW1, and AP3 B type MADS box gene), and PdDIF (a defensin gene, highly homologous to the oil palm gene EGAD). We applied transcriptomic analyses, using high throughput sequencing, to identify genes differentially expressed in the "palm heart" (the apical meristem and the region of embryonic leaves) of dwarf vs. normal trees. Among the differentially expressed genes we identified genes related to hormonal biosynthesis, perception and regulation, genes related to cell expansion, and genes related to DNA methylation. Using Representation Difference Analyses, we detected changes in the genomes of off-type trees, mainly chloroplast-derived sequences that were incorporated in the nuclear genome and sequences of transposable elements. Sequences previously identified as differing between normal and off-type trees of oil palms or banana, successfully identified variation among date palm off-types, suggesting that these represent highly labile regions of monocot genomes. The data indicate that the date palm genome, similarly to genomes of other monocot crops as oil palm and banana, is quite unstable when cells pass through a cycle of tissue culture and regeneration. Changes in DNA sequences, translocation of DNA fragments and alteration of methylation patterns occur. Consequently, patterns of gene expression are changed, resulting in abnormal phenotypes. The data can be useful for future development of tools for early identification of off-type as well as for better understanding the phenomenon of somaclonal variation during propagation in vitro.

scholarly journals Epigenetic Changes and Transcriptional Reprogramming Upon Woody Plant Grafting for Crop Sustainability in a Changing Environment

2021 ◽  
Vol 11 ◽  
Author(s):  
Aliki Kapazoglou ◽  
Eleni Tani ◽  
Evangelia V. Avramidou ◽  
Eleni M. Abraham ◽  
Maria Gerakari ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Woody Plant ◽  
Crop Improvement ◽  
Plant Performance ◽  
Agricultural Practice ◽  
Epigenetic Changes ◽  
Transcriptional Reprogramming ◽  
Woody Crop

Plant grafting is an ancient agricultural practice widely employed in crops such as woody fruit trees, grapes, and vegetables, in order to improve plant performance. Successful grafting requires the interaction of compatible scion and rootstock genotypes. This involves an intricate network of molecular mechanisms operating at the graft junction and associated with the development and the physiology of the scion, ultimately leading to improved agricultural characteristics such as fruit quality and increased tolerance/resistance to abiotic and biotic factors. Bidirectional transfer of molecular signals such as hormones, nutrients, proteins, and nucleic acids from the rootstock to the scion and vice versa have been well documented. In recent years, studies on rootstock-scion interactions have proposed the existence of an epigenetic component in grafting reactions. Epigenetic changes such as DNA methylation, histone modification, and the action of small RNA molecules are known to modulate chromatin architecture, leading to gene expression changes and impacting cellular function. Mobile small RNAs (siRNAs) migrating across the graft union from the rootstock to the scion and vice versa mediate modifications in the DNA methylation pattern of the recipient partner, leading to altered chromatin structure and transcriptional reprogramming. Moreover, graft-induced DNA methylation changes and gene expression shifts in the scion have been associated with variations in graft performance. If these changes are heritable they can lead to stably altered phenotypes and affect important agricultural traits, making grafting an alternative to breeding for the production of superior plants with improved traits. However, most reviews on the molecular mechanisms underlying this process comprise studies related to vegetable grafting. In this review we will provide a comprehensive presentation of the current knowledge on the epigenetic changes and transcriptional reprogramming associated with the rootstock–scion interaction focusing on woody plant species, including the recent findings arising from the employment of advanced—omics technologies as well as transgrafting methodologies and their potential exploitation for generating superior quality grafts in woody species. Furthermore, will discuss graft—induced heritable epigenetic changes leading to novel plant phenotypes and their implication to woody crop improvement for yield, quality, and stress resilience, within the context of climate change.

scholarly journals Discovery and Validation of Novel Methylation Markers in Helicobacter pylori-Associated Gastric Cancer

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huan Wang ◽  
Nian-Shuang Li ◽  
Cong He ◽  
Chuan Xie ◽  
Yin Zhu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastric Cancer ◽  
Dna Methylation ◽  
Helicobacter Pylori ◽  
Gene Expression Data ◽  
Functional Enrichment ◽  
Expression Data ◽  
H Pylori

Previous studies have shown that abnormal methylation is an early key event in the pathogenesis of most human cancers, contributing to the development of tumors. However, little attention has been given to the potential of DNA methylation patterns as markers for Helicobacter pylori- (H. pylori-) associated gastric cancer (GC). In this study, an integrated analysis of DNA methylation and gene expression was conducted to identify some potential key epigenetic markers in H. pylori-associated GC. DNA methylation data of 28 H. pylori-positive and 168 H. pylori-negative GC samples were compared and analyzed. We also analyzed the gene expression data of 18 H. pylori-positive and 145 H. pylori-negative GC cases. Finally, the results were verified by in vitro and in vivo experiments. A total of 5609 differentially methylated regions associated with 2454 differentially methylated genes were identified. A total of 228 differentially expressed genes were identified from the gene expression data of H. pylori-positive and H. pylori-negative GC cases. The screened genes were analyzed for functional enrichment. Subsequently, we obtained 28 genes regulated by methylation through a Venn diagram, and we identified five genes (GSTO2, HUS1, INTS1, TMEM184A, and TMEM190) downregulated by hypermethylation. HUS1, GSTO2, and TMEM190 were expressed at lower levels in GC than in adjacent samples ( P < 0.05 ). Moreover, H. pylori infection decreased HUS1, GSTO2, and TMEM190 expression in vitro and in vivo. Our study identified HUS1, GSTO2, and TMEM190 as novel methylation markers for H. pylori-associated GC.

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