scholarly journals Tet1 and Tet2 Protect DNA Methylation Canyons against Hypermethylation

2015 ◽  
Vol 36 (3) ◽  
pp. 452-461 ◽  
Author(s):  
Laura Wiehle ◽  
Günter Raddatz ◽  
Tanja Musch ◽  
Meelad M. Dawlaty ◽  
Rudolf Jaenisch ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cell Fate ◽  
Epigenetic Modification ◽  
Regulation Of Gene Expression ◽  
Mechanistic Explanation ◽  
Dna Demethylation ◽  
Double Knockout ◽  
Developmental Defects ◽  
Active Dna Demethylation ◽  
Underlying Mechanisms

DNA methylation is a dynamic epigenetic modification with an important role in cell fate specification and reprogramming. The Ten eleven translocation (Tet) family of enzymes converts 5-methylcytosine to 5-hydroxymethylcytosine, which promotes passive DNA demethylation and functions as an intermediate in an active DNA demethylation process. Tet1/Tet2 double-knockout mice are characterized by developmental defects and epigenetic instability, suggesting a requirement for Tet-mediated DNA demethylation for the proper regulation of gene expression during differentiation. Here, we used whole-genome bisulfite and transcriptome sequencing to characterize the underlying mechanisms. Our results uncover the hypermethylation of DNA methylation canyons as the genomic key feature of Tet1/Tet2 double-knockout mouse embryonic fibroblasts. Canyon hypermethylation coincided with disturbed regulation of associated genes, suggesting a mechanistic explanation for the observed Tet-dependent differentiation defects. Based on these results, we propose an important regulatory role of Tet-dependent DNA demethylation for the maintenance of DNA methylation canyons, which prevents invasive DNA methylation and allows functional regulation of canyon-associated genes.

scholarly journals Epigenetic regulations through DNA methylation and hydroxymethylation: clues for early pregnancy in decidualization

2014 ◽  
Vol 5 (2) ◽  
pp. 95-107 ◽  
Author(s):  
Fei Gao ◽  
Sanjoy K. Das
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Cell Fate ◽  
High Throughput Sequencing ◽  
Gene Expression Regulation ◽  
Epigenetic Modification ◽  
Regulation Of Gene Expression ◽  
Reproductive Organ ◽  
Epigenetic Changes ◽  
Dynamic Regulation

AbstractDNA methylation at cytosines is an important epigenetic modification that participates in gene expression regulation without changing the original DNA sequence. With the rapid progress of high-throughput sequencing techniques, whole-genome distribution of methylated cytosines and their regulatory mechanism have been revealed gradually. This has allowed the uncovering of the critical roles played by DNA methylation in the maintenance of cell pluripotency, determination of cell fate during development, and in diverse diseases. Recently, rediscovery of 5-hydroxymethylcytosine, and other types of modification on DNA, have uncovered more dynamic aspects of cell methylome regulation. The interaction of DNA methylation and other epigenetic changes remodel the chromatin structure and determine the state of gene transcription, not only permanently, but also transiently under certain stimuli. The uterus is a reproductive organ that experiences dramatic hormone stimulated changes during the estrous cycle and pregnancy, and thus provides us with a unique model for studying the dynamic regulation of epigenetic modifications. In this article, we review the current findings on the roles of genomic DNA methylation and hydroxymethylation in the regulation of gene expression, and discuss the progress of studies for these epigenetic changes in the uterus during implantation and decidualization.

scholarly journals Active DNA Demethylation in Plants

2019 ◽  
Vol 20 (19) ◽  
pp. 4683 ◽  
Author(s):  
Jara Teresa Parrilla-Doblas ◽  
Teresa Roldán-Arjona ◽  
Rafael R. Ariza ◽  
Dolores Córdoba-Cañero
Keyword(s):  
Dna Methylation ◽  
Transcriptional Activation ◽  
Excision Repair ◽  
Epigenetic Modification ◽  
Dna Demethylation ◽  
Plant Responses ◽  
Dna Glycosylases ◽  
Active Dna Demethylation ◽  
Physiological Processes ◽  
Base Excision

Methylation of cytosine (5-meC) is a critical epigenetic modification in many eukaryotes, and genomic DNA methylation landscapes are dynamically regulated by opposed methylation and demethylation processes. Plants are unique in possessing a mechanism for active DNA demethylation involving DNA glycosylases that excise 5-meC and initiate its replacement with unmodified C through a base excision repair (BER) pathway. Plant BER-mediated DNA demethylation is a complex process involving numerous proteins, as well as additional regulatory factors that avoid accumulation of potentially harmful intermediates and coordinate demethylation and methylation to maintain balanced yet flexible DNA methylation patterns. Active DNA demethylation counteracts excessive methylation at transposable elements (TEs), mainly in euchromatic regions, and one of its major functions is to avoid methylation spreading to nearby genes. It is also involved in transcriptional activation of TEs and TE-derived sequences in companion cells of male and female gametophytes, which reinforces transposon silencing in gametes and also contributes to gene imprinting in the endosperm. Plant 5-meC DNA glycosylases are additionally involved in many other physiological processes, including seed development and germination, fruit ripening, and plant responses to a variety of biotic and abiotic environmental stimuli.

scholarly journals Estradiol-Induced Epigenetically Mediated Mechanisms and Regulation of Gene Expression

2020 ◽  
Vol 21 (9) ◽  
pp. 3177 ◽  
Author(s):  
Tamás Kovács ◽  
Edina Szabó-Meleg ◽  
István M. Ábrahám
Keyword(s):  
Dna Methylation ◽  
Chromatin Remodeling ◽  
Gene Transcription ◽  
Regulation Of Gene Expression ◽  
Dna Demethylation ◽  
Gonadal Hormone ◽  
Active Dna Demethylation ◽  
Physiological Processes ◽  
Chromatin Remodeling Complexes ◽  
17Β Estradiol

Gonadal hormone 17β-estradiol (E2) and its receptors are key regulators of gene transcription by binding to estrogen responsive elements in the genome. Besides the classical genomic action, E2 regulates gene transcription via the modification of epigenetic marks on DNA and histone proteins. Depending on the reaction partner, liganded estrogen receptor (ER) promotes DNA methylation at the promoter or enhancer regions. In addition, ERs are important regulators of passive and active DNA demethylation. Furthermore, ERs cooperating with different histone modifying enzymes and chromatin remodeling complexes alter gene transcription. In this review, we survey the basic mechanisms and interactions between estrogen receptors and DNA methylation, demethylation and histone modification processes as well as chromatin remodeling complexes. The particular relevance of these mechanisms to physiological processes in memory formation, embryonic development, spermatogenesis and aging as well as in pathophysiological changes in carcinogenesis is also discussed.

scholarly journals Induced Methylation in Plants as a Crop Improvement Tool: Progress and Perspectives

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1484
Author(s):  
Clémentine Mercé ◽  
Philipp E. Bayer ◽  
Cassandria Tay Fernandez ◽  
Jacqueline Batley ◽  
David Edwards
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Epigenetic Modification ◽  
Crop Improvement ◽  
Regulation Of Gene Expression ◽  
Gene Promoters ◽  
Control Of Gene Expression ◽  
Underlying Mechanisms ◽  
Successive Generations ◽  
Methylation Patterns

The methylation of gene promoters is an epigenetic process that can have a major impact on plant phenotypes through its control of gene expression. This phenomenon can be observed as a response to stress, such as drought, cold/heat stress or pathogen infection. The transgenerational heritability of DNA methylation marks could enable breeders to fix beneficial methylation patterns in crops over successive generations. These properties of DNA methylation, its impact on the phenotype and its heritability, could be used to support the accelerated breeding of improved crop varieties. Induced DNA methylation has the potential to complement the existing plant breeding process, supporting the introduction of desirable characteristics in crops within a single generation that persist in its progeny. Therefore, it is important to understand the underlying mechanisms involved in the regulation of gene expression through DNA methylation and to develop methods for precisely modulating methylation patterns for crop improvement. Here we describe the currently available epigenetic editing tools and their advantages and limitations in the domain of crop breeding. Finally, we discuss the biological and legislative limitations currently restricting the development of epigenetic modification as a crop improvement tool.

scholarly journals TET2 coactivates gene expression through demethylation of enhancers

2018 ◽  
Vol 4 (11) ◽  
pp. eaau6986 ◽  
Author(s):  
Lu Wang ◽  
Patrick A. Ozark ◽  
Edwin R. Smith ◽  
Zibo Zhao ◽  
Stacy A. Marshall ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Regulation Of Gene Expression ◽  
Estrogen Receptor Α ◽  
Dna Demethylation ◽  
Estrogen Response ◽  
Dna Base ◽  
Modified Dna ◽  
Global Increase ◽  
Methylation Patterns

The tet methylcytosine dioxygenase 2 (TET2) enzyme catalyzes the conversion of the modified DNA base 5-methylcytosine to 5-hydroxymethylcytosine. TET2 is frequently mutated or dysregulated in multiple human cancers, and loss of TET2 is associated with changes in DNA methylation patterns. Here, using newly developed TET2-specific antibodies and the estrogen response as a model system for studying the regulation of gene expression, we demonstrate that endogenous TET2 occupies active enhancers and facilitates the proper recruitment of estrogen receptor α (ERα). Knockout of TET2 by CRISPR-CAS9 leads to a global increase of DNA methylation at enhancers, resulting in attenuation of the estrogen response. We further identified a positive feedback loop between TET2 and ERα, which further requires MLL3 COMPASS at these enhancers. Together, this study reveals an epigenetic axis coordinating a transcriptional program through enhancer activation via DNA demethylation.

scholarly journals DNA demethylation by ROS1a in rice vegetative cells promotes methylation in sperm

2019 ◽  
Vol 116 (19) ◽  
pp. 9652-9657 ◽  
Author(s):  
M. Yvonne Kim ◽  
Akemi Ono ◽  
Stefan Scholten ◽  
Tetsu Kinoshita ◽  
Daniel Zilberman ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Vegetative Cell ◽  
Seed Viability ◽  
Dna Demethylation ◽  
Central Cell ◽  
Dna Glycosylase ◽  
Rice Seed ◽  
Vegetative Cells ◽  
Active Dna Demethylation ◽  
Cell Genome

Epigenetic reprogramming is required for proper regulation of gene expression in eukaryotic organisms. In Arabidopsis, active DNA demethylation is crucial for seed viability, pollen function, and successful reproduction. The DEMETER (DME) DNA glycosylase initiates localized DNA demethylation in vegetative and central cells, so-called companion cells that are adjacent to sperm and egg gametes, respectively. In rice, the central cell genome displays local DNA hypomethylation, suggesting that active DNA demethylation also occurs in rice; however, the enzyme responsible for this process is unknown. One candidate is the rice REPRESSOR OF SILENCING1a (ROS1a) gene, which is related to DME and is essential for rice seed viability and pollen function. Here, we report genome-wide analyses of DNA methylation in wild-type and ros1a mutant sperm and vegetative cells. We find that the rice vegetative cell genome is locally hypomethylated compared with sperm by a process that requires ROS1a activity. We show that many ROS1a target sequences in the vegetative cell are hypomethylated in the rice central cell, suggesting that ROS1a also demethylates the central cell genome. Similar to Arabidopsis, we show that sperm non-CG methylation is indirectly promoted by DNA demethylation in the vegetative cell. These results reveal that DNA glycosylase-mediated DNA demethylation processes are conserved in Arabidopsis and rice, plant species that diverged 150 million years ago. Finally, although global non-CG methylation levels of sperm and egg differ, the maternal and paternal embryo genomes show similar non-CG methylation levels, suggesting that rice gamete genomes undergo dynamic DNA methylation reprogramming after cell fusion.

scholarly journals Histone acetylation recruits the SWR1 complex to regulate active DNA demethylation in Arabidopsis

2019 ◽  
Vol 116 (33) ◽  
pp. 16641-16650 ◽  
Author(s):  
Wen-Feng Nie ◽  
Mingguang Lei ◽  
Mingxuan Zhang ◽  
Kai Tang ◽  
Huan Huang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Conceptual Framework ◽  
Histone Acetylation ◽  
Chromatin Remodeling ◽  
Nuclear Protein ◽  
Dna Demethylation ◽  
Specific Target ◽  
Active Dna Demethylation ◽  
Chromatin Remodeling Complex ◽  
Genomic Regions

Active DNA demethylation is critical for controlling the DNA methylomes in plants and mammals. However, little is known about how DNA demethylases are recruited to target loci, and the involvement of chromatin marks in this process. Here, we identify 2 components of the SWR1 chromatin-remodeling complex, PIE1 and ARP6, as required for ROS1-mediated DNA demethylation, and discover 2 SWR1-associated bromodomain-containing proteins, AtMBD9 and nuclear protein X1 (NPX1). AtMBD9 and NPX1 recognize histone acetylation marks established by increased DNA methylation 1 (IDM1), a known regulator of DNA demethylation, redundantly facilitating H2A.Z deposition at IDM1 target loci. We show that at some genomic regions, H2A.Z and DNA methylation marks coexist, and H2A.Z physically interacts with ROS1 to regulate DNA demethylation and antisilencing. Our results unveil a mechanism through which DNA demethylases can be recruited to specific target loci exhibiting particular histone marks, providing a conceptual framework to understand how chromatin marks regulate DNA demethylation.

scholarly journals Vitamin C Transporters and Their Implications in Carcinogenesis

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3869
Author(s):  
Kinga Linowiecka ◽  
Marek Foksinski ◽  
Anna A. Brożyna
Keyword(s):  
Vitamin C ◽  
Cancer Biology ◽  
Redox Homeostasis ◽  
Regulation Of Gene Expression ◽  
Dna Demethylation ◽  
Altered Expression ◽  
Tet Proteins ◽  
Active Dna Demethylation ◽  
Hypoxic State

Vitamin C is implicated in various bodily functions due to its unique properties in redox homeostasis. Moreover, vitamin C also plays a great role in restoring the activity of 2-oxoglutarate and Fe2+ dependent dioxygenases (2-OGDD), which are involved in active DNA demethylation (TET proteins), the demethylation of histones, and hypoxia processes. Therefore, vitamin C may be engaged in the regulation of gene expression or in a hypoxic state. Hence, vitamin C has acquired great interest for its plausible effects on cancer treatment. Since its conceptualization, the role of vitamin C in cancer therapy has been a controversial and disputed issue. Vitamin C is transferred to the cells with sodium dependent transporters (SVCTs) and glucose transporters (GLUT). However, it is unknown whether the impaired function of these transporters may lead to carcinogenesis and tumor progression. Notably, previous studies have identified SVCTs’ polymorphisms or their altered expression in some types of cancer. This review discusses the potential effects of vitamin C and the impaired SVCT function in cancers. The variations in vitamin C transporter genes may regulate the active transport of vitamin C, and therefore have an impact on cancer risk, but further studies are needed to thoroughly elucidate their involvement in cancer biology.

Regulation of gene expression by DNA methylation with cytotoxic T lymphocytes evaluation in consensus molecular subtypes of colorectal cancer.

2020 ◽  
Vol 38 (5_suppl) ◽  
pp. 25-25
Author(s):  
Yuanyuan Shen ◽  
Justin Hummel ◽  
Isabel Cristina Trindade ◽  
Christos Papageorgiou ◽  
Chi-Ren Shyu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
Dna Methylation ◽  
Molecular Subtypes ◽  
Epigenetic Modification ◽  
Pearson Correlation ◽  
Critical Role ◽  
Regulation Of Gene Expression ◽  
The Cancer Genome Atlas ◽  
Highly Correlated

25 Background: Low cytotoxic T lymphocyte (CTLs) infiltration in colorectal cancer (CRC) tumors is a challenge to treatment with immune checkpoint inhibitors. Consensus molecular subtypes (CMS) classify patients based on tumor attributes, and CMS1 patients include the majority of patients with high CTL infiltration and “inflamed” tumors. Epigenetic modification plays a critical role in gene expression and therapy resistance. Therefore, in this study we compared DNA methylation, gene expression, and CTL infiltration of CMS1 patients to other CMS groups to determine targets for improving immunotherapy in CRC. Methods: RNA-seq (n = 511) and DNA methylation (n = 316) from The Cancer Genome Atlas databases were used to determine gene expression and methylation profiles based on CMSs. CMS1 was used as a reference and compared to other subtypes (CMS2-4). Microenvironment Cell Populations- counter (MCPcounter) was used to determine tumor CTL infiltration. Genes with significantly different expression (p < 0.01, LogFC≥|1.5|) and difference of mean methylation β value ≥|0.25| were integrated for Pearson correlation coefficient analysis with MCPcounter score (r > |0.7|). Results: Comparing CMS1 and CMS2, ARHGAP9, TBX21, and LAG3 were differentially methylated and correlated with CTL scores. ARHGAP9 and TBX21 were decreased and hypomethylated in CMS2. Comparing CMS1 and CMS3, ARHGAP9, TBX21, FMNL1, HLA-DPB1, and STX11 were downregulated in CMS3 and highly correlated with CTL scores. ARHGAP9, FMNL1, HLA-DPB1, and STX11 were hypomethylated in CMS3 and TBX21 was methylated in both, but had a higher methylation ratio in CMS1. Comparing CMS1 and CMS4, TBX21 was the only gene downregulated, hypomethylated, and highly correlated with CTL scores in CMS4 patients. Conclusions: We found six genes differentially expressed, differentially methylated, and highly correlated with CTL infiltration when comparing CMS1 to other CMS groups. Specifically, TBX21 was the only gene highly correlated with CTL scores with differential gene expression and methylation in CMS2-4 when compared to CMS1. Thus, T-bet may be a critical regulator of T cell responses in CRC.

scholarly journals DNA Methylation Reprogramming during Sex Determination and Transition in Zebrafish

2020 ◽  
Author(s):  
Xinxin Wang ◽  
Xin Ma ◽  
Gaobo Wei ◽  
Weirui Ma ◽  
Zhen Zhang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Sex Determination ◽  
Sexual Development ◽  
Epigenetic Modification ◽  
Sex Differentiation ◽  
Primordial Germ Cells ◽  
Regulation Of Gene Expression ◽  
Adult Zebrafish ◽  
Germline Development ◽  
Male Sex

AbstractIt is a mystery about sex determination and sexual plasticity in species without sex chromosomes. DNA methylation is a prevalent epigenetic modification in vertebrates, which has been shown to involve in the regulation of gene expression and embryo development. However, it remains unclear about how DNA methylation regulates sexual development. To elucidate it, we used zebrafish to investigate DNA methylation reprogramming during juvenile germ cell development and adult female-to-male sex transition. We revealed that primordial germ cells (PGCs) undergo significant DNA methylation reprogramming during germline development and set to an oocyte/ovary-like pattern at 9 days post fertilization (9 dpf). When blocking DNMTs activity in juveniles after 9 dpf, the zebrafish preferably develops into females. We also show that Tet3 involves in PGC development. Notably, we find that DNA methylome reprogramming during adult zebrafish sex transition is similar to the reprogramming during the sex differentiation from 9 dpf PGCs to sperm. Furthermore, inhibiting DNMTs activity can prevent the female-to-male sex transition, suggesting that methylation reprogramming is required for zebrafish sex transition. In summary, DNA methylation plays important roles in zebrafish germline development and sexual plasticity.

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