Analysis of DNA Methylation Patterns Associated with In Vitro Propagated Globe Artichoke Plants Using an EpiRADseq-Based Approach

Globe artichoke represents one of the main horticultural species of the Mediterranean basin, and ‘Spinoso sardo’ is the most widespread and economically relevant varietal type in Sardinia, Italy. In the last decades, in vitro culture of meristematic apices has increased the frequency of aberrant plants in open-field production. These off-type phenotypes showed highly pinnate-parted leaves and late inflorescence budding, and emerged from some branches of the true-to-type ‘Spinoso sardo’ plants. This phenomenon cannot be foreseen and is reversible through generations, suggesting the occurrence of epigenetic alterations. Here, we report an exploratory study on DNA methylation patterns in off-type/true-to-type globe artichoke plants, using a modified EpiRADseq technology, which allowed the identification of 2,897 differentially methylated loci (DML): 1,998 in CG, 458 in CHH, and 441 in CHG methylation contexts of which 720, 88, and 152, respectively, were in coding regions. Most of them appeared involved in primary metabolic processes, mostly linked to photosynthesis, regulation of flower development, and regulation of reproductive processes, coherently with the observed phenotype. Differences in the methylation status of some candidate genes were integrated with transcriptional analysis to test whether these two regulation levels might interplay in the emergence and spread of the ‘Spinoso sardo’ non-conventional phenotype.

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Genome-wide DNA methylation patterns reveal clinically relevant predictive and prognostic subtypes in osteosarcoma

10.1101/2020.11.26.20238584 ◽

2020 ◽

Author(s):

Christopher E. Lietz ◽

Erik T. Newman ◽

Andrew D. Kelly ◽

Santiago A. Lozano-Calderon ◽

David H. Ebb ◽

...

Keyword(s):

Dna Methylation ◽

Methylation Pattern ◽

Transcriptional Analysis ◽

Chemotherapy Response ◽

Methylation Array ◽

Genome Wide ◽

Recurrent Mutations ◽

Methylation Patterns ◽

Genomic Methylation

ABSTRACTBackgroundOsteosarcoma (OSA) is an aggressive malignancy predominantly affecting children and young-adults. Genetic analysis has characterized very few recurrent mutations in OSA, and an improved understanding of interpatient tumor heterogeneity is needed for clinical management.MethodsWe analyzed genome-wide DNA methylation in primary OSA tumors from the NCI Therapeutically Applicable Research to Generate Effective Treatments (TARGET) program (n = 83) profiled using the Illumina 450K methylation array. We tested if broad genomic methylation predicted outcomes and defined supervised methylomic signatures predictive of Recurrence Free Survival (RFS), Chemotherapy Response (CR), and Metastatic disease at Diagnosis (MetDx). We assessed methylation pattern reproducibility in two independent clinical datasets (n = 28 and 34) and in an in vitro dataset (n = 11). Correlations between genomic methylation and transcription were tested using TARGET RNA-seq data. An in silico pharmacogenomic screen was performed to identify agents for future stratified application.ResultsGenome-wide methylation defined two subgroups. Relatively hypomethylated tumors experienced better chemotherapy response (Odds Ratio = 6.429, Fisher’s p = 0.007), longer RFS (metastatic, median 2.3 vs 26.7 months, localized, median 63.5 vs 104.7 months, stratified log-rank p = 0.006), and Overall Survival (p = 5×10-4) than hypermethylated tumors. Robust genomic methylation signatures predictive of RFS and CR were defined, and the signatures’ methylation patterns were reproducible in the independent clinical and in vitro datasets. The RFS signature was enriched for intragenic sites, whereas the CR signature and clinically relevant genome-wide methylation patterns were enriched for intergenic sites. Normal-tissue-like methylation patterns were associated with poor prognosis and in vitro analysis suggested that the methylation signatures are associated with tumor aggressiveness. Downstream transcriptional analysis revealed that genes annotated to the RFS methylation signature were also predictive survival. The transcriptional program represented in the RFS signature included several critical cellular pathways, whereas the CR signature was associated with much fewer known pathways, possibly reflecting a much broader cellular “methylation state” related to chemoresponse. A pharmacogenomic screen identified potential therapies, including epigenomic modifiers, for future stratified clinical application.ConclusionGenomic methylation offers insight into patient prognosis and could be a useful tool for developing alternate adjuvant therapeutic strategies.

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Abstract 40: Disturbed Flow Alters Genomewide DNA Methylation Patterns, Regulating Endothelial Gene Expression and Atherosclerosis

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.34.suppl_1.40 ◽

2014 ◽

Vol 34 (suppl_1) ◽

Author(s):

Jessilyn Dunn ◽

Haiwei Qiu ◽

Soyeon Kim ◽

Daudi Jjingo ◽

Ryan Hoffman ◽

...

Keyword(s):

Gene Expression ◽

Dna Methylation ◽

Dna Methyltransferase ◽

Methylation Status ◽

Western Diet ◽

Dependent Manner ◽

Gene Promoters ◽

Genome Wide ◽

Methylation Patterns ◽

Endothelial Gene Expression

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.

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DNA methylation and gene expression changes derived from assisted reproductive technologies can be decreased by reproductive fluids

eLife ◽

10.7554/elife.23670 ◽

2017 ◽

Vol 6 ◽

Cited By ~ 49

Author(s):

Sebastian Canovas ◽

Elena Ivanova ◽

Raquel Romar ◽

Soledad García-Martínez ◽

Cristina Soriano-Úbeda ◽

...

Keyword(s):

Dna Methylation ◽

Assisted Reproductive Technologies ◽

Reproductive Technologies ◽

Cell Number ◽

Rna Seq ◽

Methylation Analysis ◽

Number Of Children ◽

Methylation Patterns

The number of children born since the origin of Assisted Reproductive Technologies (ART) exceeds 5 million. The majority seem healthy, but a higher frequency of defects has been reported among ART-conceived infants, suggesting an epigenetic cost. We report the first whole-genome DNA methylation datasets from single pig blastocysts showing differences between in vivo and in vitro produced embryos. Blastocysts were produced in vitro either without (C-IVF) or in the presence of natural reproductive fluids (Natur-IVF). Natur-IVF embryos were of higher quality than C-IVF in terms of cell number and hatching ability. RNA-Seq and DNA methylation analyses showed that Natur-IVF embryos have expression and methylation patterns closer to in vivo blastocysts. Genes involved in reprogramming, imprinting and development were affected by culture, with fewer aberrations in Natur-IVF embryos. Methylation analysis detected methylated changes in C-IVF, but not in Natur-IVF, at genes whose methylation could be critical, such as IGF2R and NNAT.

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Application of the MSAP Technique to Evaluate Epigenetic Changes in Plant Conservation

International Journal of Molecular Sciences ◽

10.3390/ijms21207459 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7459

Author(s):

María Elena González-Benito ◽

Miguel Ángel Ibáñez ◽

Michela Pirredda ◽

Sara Mira ◽

Carmen Martín

Keyword(s):

Dna Methylation ◽

In Situ Conservation ◽

Plant Conservation ◽

Ex Situ ◽

Conservation Strategies ◽

Regenerated Plants ◽

Before And After ◽

Methylation Patterns

Epigenetic variation, and particularly DNA methylation, is involved in plasticity and responses to changes in the environment. Conservation biology studies have focused on the measurement of this variation to establish demographic parameters, diversity levels and population structure to design the appropriate conservation strategies. However, in ex situ conservation approaches, the main objective is to guarantee the characteristics of the conserved material (phenotype and epi-genetic). We review the use of the Methylation Sensitive Amplified Polymorphism (MSAP) technique to detect changes in the DNA methylation patterns of plant material conserved by the main ex situ plant conservation methods: seed banks, in vitro slow growth and cryopreservation. Comparison of DNA methylation patterns before and after conservation is a useful tool to check the fidelity of the regenerated plants, and, at the same time, may be related with other genetic variations that might appear during the conservation process (i.e., somaclonal variation). Analyses of MSAP profiles can be useful in the management of ex situ plant conservation but differs in the approach used in the in situ conservation. Likewise, an easy-to-use methodology is necessary for a rapid interpretation of data, in order to be readily implemented by conservation managers.

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Detection of LINE-1 hypomethylation in cfDNA of Esophageal Adenocarcinoma Patients

International Journal of Molecular Sciences ◽

10.3390/ijms21041547 ◽

2020 ◽

Vol 21 (4) ◽

pp. 1547 ◽

Cited By ~ 2

Author(s):

Elisa Boldrin ◽

Matteo Curtarello ◽

Marco Dallan ◽

Rita Alfieri ◽

Stefano Realdon ◽

...

Keyword(s):

Dna Methylation ◽

Esophageal Adenocarcinoma ◽

Methodological Approach ◽

Methylation Status ◽

Dna Amplification ◽

Restriction Enzymes ◽

Poor Quality ◽

Bisulfite Conversion ◽

Dna Hypomethylation ◽

Methylation Patterns

DNA methylation plays an important role in cancer development. Cancer cells exhibit two types of DNA methylation alteration: site-specific hypermethylation at promoter of oncosuppressor genes and global DNA hypomethylation. This study evaluated the methylation patterns of long interspersed nuclear element (LINE-1) sequences which, due to their relative abundance in the genome, are considered a good surrogate indicator of global DNA methylation. LINE-1 methylation status was investigated in the cell-free DNA (cfDNA) of 21 patients, 19 with esophageal adenocarcinoma (EADC) and 2 with Barrett’s esophagus (BE). The two BE patients and one EADC patient were also analyzed longitudinally. Methylation status was analyzed using restriction enzymes and DNA amplification. This methodology was chosen to avoid bisulfite conversion, which we considered inadequate for cfDNA analysis. Indeed, cfDNA is characterized by poor quality and low concentration, and bisulfite conversion might worsen these conditions. Results showed that hypomethylated LINE-1 sequences are present in EADC cfDNA. Furthermore, longitudinal studies in BE suggested a correlation between methylation status of LINE-1 sequences in cfDNA and progression to EADC. In conclusion, our study indicated the feasibility of our methodological approach to detect hypomethylation events in cfDNA from EADC patients, and suggests LINE-1 methylation analysis as a new possible molecular assay to integrate into patient monitoring.

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53 IMPACTS OF USING PROCAINE AS A DNA-DEMETHYLATING AGENT IN IN VITRO CULTURE OF BOVINE CELLS

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab53 ◽

2011 ◽

Vol 23 (1) ◽

pp. 132

Author(s):

V. A. Michalczechen-Lacerda ◽

F. C. Rodrigues ◽

R. V. de Sousa ◽

R. Rumpf ◽

M. M. Franco

Keyword(s):

Dna Methylation ◽

Cell Viability ◽

In Vitro Culture ◽

Cytogenetic Analysis ◽

Imprinted Genes ◽

Demethylating Agent ◽

Chromosome Integrity ◽

Methylation Patterns ◽

Number Of Cells

Euchromatin and heterochromatin organisation define the specificity of each cell type. This structure is controlled by epigenetic modifications and the DNA methylation is one of the best known for inducing transcriptional repression. Recently, procaine was uncovered as a DNA-demethylating agent, but there are few reports about its dynamic epigenetic action on somatic cells. Mono-allelic expression of imprinted genes is controlled by DNA methylation and inherited to somatic tissues of a sex-specific manner. The aim was to investigate the effects of using procaine, a DNA-demethylating agent, in in vitro culture of bovine (Bos taurus indicus) fibroblast for 72 h (passage 4). We have evaluated cell viability, chromosome integrity, and DNA methylation patterns. To evaluate cell viability, we have used trypan blue 0.4%. To evaluate chromosome integrity, we have used conventional cytogenetic analysis. To investigate DNA methylation patterns, we have analysed 2 differentially methylated regions (DMR) located into the exon 10 of IGF2 and exon 1 of XIST imprinted genes, using the bisulfite sequencing method (EZ DNA methylation kit, Zymo Research, Orange, CA, USA). After bisulfite treatment and nested-PCR, the amplicons were separated in agarose gel electrophoresis, purified with GenClean III kit (MP Biomedicals, Irvine, CA, USA), cloned in a pGEM-T easy vector system (Promega, Madison, WI), and sequenced. The DNA sequences were analysed using the BiQ Analyzer v. 2.0 (2008) software. The cell viability data were analysed using ANOVA and Tukey or Kruskal-Wallis and Mann-Whitney tests, and the methylation status were analysed using Student’s t-test or Mann-Whitney tests in the Prophet software (BBN Systems and Technologies). Cell culture using 0.1 mM or 0.5 mM of procaine were viable and the number of cells with intact membrane was higher than the control and 2.0 mM of procaine groups (P ≤ 0.05). The total number of cells was lower in the group with 2.0 mM of procaine (P ≤ 0.01). Cytogenetic analysis showed no differences among the groups, with no chromosome abnormalities detected. The methylation pattern was not different for both DMR evaluated among the groups. We have observed that there was a beneficial effect to the cells that have received supplementation with 0.1 mM or 0.5 mM of procaine, because there was an increase in the number of viable cells without chromosomal abnormalities. We cannot ignore that a global DNA demethylation may have occurred, which was not detected in the specific analysed regions. The results obtained here may contribute to improving the efficiency of animal cloning, transgenic animal production, and the knowledge about stem cells. Supported by Embrapa Genetic Resources and Biotechnology and CAPES.

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The Effects of Maternal and Postnatal Dietary Methyl Nutrients on Epigenetic Changes that Lead to Non-Communicable Diseases in Adulthood

International Journal of Molecular Sciences ◽

10.3390/ijms21093290 ◽

2020 ◽

Vol 21 (9) ◽

pp. 3290 ◽

Cited By ~ 1

Author(s):

Raniru S. Randunu ◽

Robert F. Bertolo

Keyword(s):

Dna Methylation ◽

Metabolic Pathways ◽

Dietary Intervention ◽

Infant Nutrition ◽

Communicable Diseases ◽

Epigenetic Alterations ◽

Non Communicable Diseases ◽

Nutrient Manipulation ◽

Methylation Patterns ◽

Epigenetic Patterns

The risk for non-communicable diseases in adulthood can be programmed by early nutrition. This programming is mediated by changes in expression of key genes in various metabolic pathways during development, which persist into adulthood. These developmental modifications of genes are due to epigenetic alterations in DNA methylation patterns. Recent studies have demonstrated that DNA methylation can be affected by maternal or early postnatal diets. Because methyl groups for methylation reactions come from methionine cycle nutrients (i.e., methionine, choline, betaine, folate), deficiency or supplementation of these methyl nutrients can directly change epigenetic regulation of genes permanently. Although many studies have described the early programming of adult diseases by maternal and infant nutrition, this review discusses studies that have associated early dietary methyl nutrient manipulation with direct effects on epigenetic patterns that could lead to chronic diseases in adulthood. The maternal supply of methyl nutrients during gestation and lactation can alter epigenetics, but programming effects vary depending on the timing of dietary intervention, the type of methyl nutrient manipulated, and the tissue responsible for the phenotype. Moreover, the postnatal manipulation of methyl nutrients can program epigenetics, but more research is needed on whether this approach can rescue maternally programmed offspring.

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STEM-27. miR-10b-5p MODULATES 5hmC EXPRESSION AND THE STEM-LIKE PHENOTYPE IN GBM

Neuro-Oncology ◽

10.1093/neuonc/noaa215.844 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii202-ii202

Author(s):

Harmon Khela ◽

Sweta Sudhir ◽

Maria Lugo-Fagundo ◽

Bachchu Lal ◽

Hernando Lopez-Bertoni ◽

...

Keyword(s):

Dna Methylation ◽

Stem Cell Markers ◽

Tumor Initiation ◽

Epigenetic Alterations ◽

Sox2 Expression ◽

Initiation And Propagation ◽

Xenograft Models ◽

Non Coding Rnas ◽

Methylation Patterns ◽

Sphere Formation

Abstract Epigenetic alterations such as DNA methylation and dysregulation of non-coding RNAs (e.g. miRNAs) are found in all types of cancer and are thought to play important roles in tumorigenesis. GBM is characterized by small subsets of cells, referred to as glioma stem cells (GSCs), that display stem-like properties implicated in tumor initiation, therapeutic resistance, and recurrence. DNA methylation patterns are altered in GBM and GSCs and are thought to play critical roles in tumor initiation and propagation. DNA methylation is a reversible process catalyzed, in part, by the ten-eleven translocation (TET) family of enzymes. These enzymes function as deoxygenases that catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Multiple studies found negative correlations between 5hmC levels and glioma grade and loss of 5hmC correlates with poor prognosis of GBM patients. However, the mechanisms leading to the loss of 5hmC in glioma and the role this phenomenon plays in gliomagenesis remains poorly understood. We found that Sox2 expression decreases TET2 expression and its product 5hmC in GSCs and identified miR-10b-5p as a molecular intermediary of this process. We show that miR-10b-5p expression is high in GBM compared to non-tumor in clinical specimens and high levels of this miRNA correlate with poor patient outcome. Expression of transgenic miR-10b-5p enhanced sphere formation capacity of GSCs and the expression of stem cell markers and drivers. Additionally, using a combination of molecular and biochemical endpoints, we show that miR-10b-5p modifies 5hmC levels by regulating TET2 in GSCs. Finally, we show that repression of miR-10b-5p increases 5hmC levels and inhibits tumor propagation in GBM xenograft models. Taken together, these results present a new molecular mechanism that controls 5hmC and the tumor propagating capacity of GSCs and suggests that miR-10b-5p inhibition and other strategies for enhancing TET2 function can be developed to treat GBM.

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High Throughput Methylation Arrays Allow for Identification of Complex Methylation Patterns in MDS.

Blood ◽

10.1182/blood.v110.11.2437.2437 ◽

2007 ◽

Vol 110 (11) ◽

pp. 2437-2437

Author(s):

Ying Jiang ◽

Christine L. OKeefe ◽

Andrew Dunbar ◽

Anjali Advani ◽

Mikkael A. Sekeres ◽

...

Keyword(s):

Dna Methylation ◽

Tumor Suppressor ◽

High Throughput ◽

Tumor Suppressor Genes ◽

Methylation Status ◽

Epigenetic Silencing ◽

Low Grade ◽

High Grade ◽

Methylation Patterns ◽

Hypermethylated Genes

Abstract Genomic imprinting and epigenetic silencing determine tissue-specific methylation patterns. Altered methylation of CpG islands within gene promoters has been hypothesized as one pathogenetic mechanism operative in myelodysplastic syndrome (MDS). Promoter hypermethylation of various empirically selected tumor suppressor genes has been found in MDS prompting application of hypomethylating drugs in this disease. Identification of hypermethylated genes predicting response to these drugs would have a major impact on clinical practice. However, to date methylation-based prognostic algorithms have not been established. Global analysis of DNA methylation patterns may help to identify hypermethylated genes/promoters associated with the pathogenesis of MDS. Recently, microarray-based DNA methylation analysis platforms enabled a powerful, high-throughput analysis of the methylation status of hundreds of genes. The GoldenGate Methylation Cancer Panel I, spanning 1,536 independent CpG sites selected from 807 selected genes was applied to determine the methylation status in MDS patients (N=51; 21 low grade (RA, MDS-U, RARS or RCMD), 26 high grade (AML or RAEB) and 4 CMML). The methylation status was determined based on an internal reference and compared to healthy controls (N=22). Methylation values were averaged among the patients or analyzed separately for each patient in comparison to average values obtained in controls. Overall, controls showed a lesser degree of methylation than advanced MDS patients (average intensity 0.326 vs. 0.339, p<0.05). Subsequently, we concentrated on hypermethylated genes. There were no genes uniformly hypermethylated in all patients. For 70%, 50%, and 30% of patients with advanced MDS, 1, 26, and 85 loci were concordantly hypermethylated, while in 70%, 50% and 30% of low risk patients 5, 23 and 31 were hypermethylated, respectively. The most consistently hypermethylated genes (>50% of patients), included tumor suppressor genes (DCC, SLC22A18, FAT, TUSC3), genes involved in DNA repair (OGG1, DDB2, BCR, PARP1), cell cycle control (DBC1, SMARCB1), differentiation (MYOD1, TDGF1, FGF2, NOTCH4) and apoptosis (HDAC1, ALOX12, AXIN1). Despite the variability, the aberrant methylation spectrum in CMML, low grade MDS and high grade MDS showed significant overlap (for example FZD9, IL16, EVI2A, MBD2 and BCR), which suggests that these genes may relate to the common tumorigenesis in MDS. Certain genes show specific methylation correlating to the morphologic diagnosis and may serve as diagnostic markers. For example, the promoter of HDAC1 is hypomethylated in 81% of sAML/RAEB1/2 patients but hypermethylated in 81% of low risk cases. To assess the link between epigenetic changes and chromosomal abnormalities, we also investigated methylation pattern of MDS with del5q for selected genes at the 5q locus. Some genes that are involved in apoptosis (WNT1, TNF receptor) and proliferation (MAP3K8, CSF3) were found to be hypermethylated in comparison to controls, suggesting that epigenetic silencing may enhance the effect of haploinsuffciency for some of the genes. In sum, our study, the first application of a high-throughput microarray methylation assay in MDS, demonstrates that complex methylation patterns exist in MDS and may allow for identification for clinically relevant methylation markers.

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Reprogramming DNA methylation in the mammalian life cycle: building and breaking epigenetic barriers

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0330 ◽

2013 ◽

Vol 368 (1609) ◽

pp. 20110330 ◽

Cited By ~ 261

Author(s):

Stefanie Seisenberger ◽

Julian R. Peat ◽

Timothy A. Hore ◽

Fátima Santos ◽

Wendy Dean ◽

...

Keyword(s):

Dna Methylation ◽

Life Cycle ◽

Cell Fate ◽

Excision Repair ◽

Primordial Germ Cells ◽

Biological Significance ◽

Epigenetic Reprogramming ◽

Developmental Potential ◽

Methylation Patterns

In mammalian development, epigenetic modifications, including DNA methylation patterns, play a crucial role in defining cell fate but also represent epigenetic barriers that restrict developmental potential. At two points in the life cycle, DNA methylation marks are reprogrammed on a global scale, concomitant with restoration of developmental potency. DNA methylation patterns are subsequently re-established with the commitment towards a distinct cell fate. This reprogramming of DNA methylation takes place firstly on fertilization in the zygote, and secondly in primordial germ cells (PGCs), which are the direct progenitors of sperm or oocyte. In each reprogramming window, a unique set of mechanisms regulates DNA methylation erasure and re-establishment. Recent advances have uncovered roles for the TET3 hydroxylase and passive demethylation, together with base excision repair (BER) and the elongator complex, in methylation erasure from the zygote. Deamination by AID, BER and passive demethylation have been implicated in reprogramming in PGCs, but the process in its entirety is still poorly understood. In this review, we discuss the dynamics of DNA methylation reprogramming in PGCs and the zygote, the mechanisms involved and the biological significance of these events. Advances in our understanding of such natural epigenetic reprogramming are beginning to aid enhancement of experimental reprogramming in which the role of potential mechanisms can be investigated in vitro . Conversely, insights into in vitro reprogramming techniques may aid our understanding of epigenetic reprogramming in the germline and supply important clues in reprogramming for therapies in regenerative medicine.

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