CpG methylation of an X-linked transgene is determined by somatic events postfertilization and not germline imprinting

Development ◽  
1988 ◽  
Vol 104 (2) ◽  
pp. 235-244
Author(s):  
A. Collick ◽  
W. Reik ◽  
S.C. Barton ◽  
A.H. Surani
Keyword(s):  
Dna Methylation ◽  
X Chromosome ◽  
De Novo ◽  
Cpg Methylation ◽  
Parental Origin ◽  
Cpg Dinucleotides ◽  
Inactive State ◽  
Methylation Of Dna ◽  
Methylation Patterns ◽  
Extraembryonic Tissues

The process of X-inactivation in mammals requires at least two events, the initiation of inactivation and the maintenance of the inactive state. One possible mechanism of control is by methylation of DNA at CpG dinucleotides to maintain the inactive state. Furthermore, the paternal X-chromosome is frequently inactivated in the extraembryonic membranes. The relationship between the parental origin of the chromosome, nonrandom inactivation and DNA methylation is not clear. In this paper, we report on the CpG methylation of an X-linked transgene, CAT-32. The levels of methylation in embryonic, extraembryonic and germline cells indicates that the modifications of the transgene are broadly similar to those reported for endogenous X-linked genes. Interestingly, the methylation of CAT-32 transgene in extraembryonic tissues displays patterns that could be linked to the germline origin of each allele. Hence, the maternally derived copy of CAT-32 was relatively undermethylated when compared to the paternal one. The changes in DNA methylation were attributed to de novo methylation occurring after fertilization, most probably during differentiation of extraembryonic tissues. In order to determine whether or not the patterns of DNA methylation reflected the germline origin of the X-chromosome, we constructed triploid embryos specifically to introduce two maternal X-chromosomes in the same embryo. In some of these triploid conceptuses, methylation patterns characteristic of the paternally derived transgene were observed. This observation indicates that the methylation patterns are not necessarily dependent on the parental origin of the X-chromosome, but could be changed by somatic events after fertilization. One of the more likely mechanisms is methylation of the transgene following inactivation of the X-chromosome in extraembryonic tissues.

Changes in DNA methylation during mouse embryonic development in relation to X-chromosome activity and imprinting

1990 ◽  
Vol 326 (1235) ◽  
pp. 299-312 ◽  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Embryonic Development ◽  
X Chromosome ◽  
De Novo ◽  
Germ Line ◽  
X Chromosome Inactivation ◽  
Chromosome Inactivation ◽  
Chromatin Configuration ◽  
Methylation Patterns

Changing DNA methylation patterns during embryonic development are discussed in relation to differential gene expression, changes in X-chromosome activity and genomic imprinting. Sperm DNA is more methylated than oocyte DNA, both overall and for specific sequences. The methylation difference between the gametes could be one of the mechanisms (along with chromatin structure) regulating initial differences in expression of parental alleles in early development. There is a loss of methylation during development from the morula to the blastocyst and a marked decrease in methylase activity. De novo methylation becomes apparent around the time of implantation and occurs to a lesser extent in extra-embryonic tissue DNA. In embryonic DNA, de novo methylation begins at the time of random X-chromosome inactivation but it continues to occur after X-chromosome inactivation and may be a mechanism that irreversibly fixes specific patterns of gene expression and X-chromosome inactivity in the female. The germ line is probably delineated before extensive de novo methylation and hence escapes this process. The marked undermethylation of the germ line DNA may be a prerequisite for X-chromosome reactivation. The process underlying reactivation and removal of parent-specific patterns of gene expression may be changes in chromatin configuration associated with meiosis and a general reprogramming of the germ line to developmental totipotency.

scholarly journals Conserved Methylation Patterns of Human Papillomavirus Type 16 DNA in Asymptomatic Infection and Cervical Neoplasia

2004 ◽  
Vol 78 (23) ◽  
pp. 12762-12772 ◽  
Author(s):  
Mina Kalantari ◽  
Itzel E. Calleja-Macias ◽  
Devansu Tewari ◽  
Bjørn Hagmar ◽  
Kathrine Lie ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Human Papillomavirus ◽  
Defense Mechanism ◽  
De Novo ◽  
Pcr Amplification ◽  
Clinical Samples ◽  
Long Control Region ◽  
Hpv 16 ◽  
Cpg Dinucleotides ◽  
Methylation Patterns

ABSTRACT DNA methylation contributes to the chromatin conformation that represses transcription of human papillomavirus type16 (HPV-16), which is prevalent in the etiology of cervical carcinoma. In an effort to clarify the role of this phenomenon in the regulation and carcinogenicity of HPV-16, 115 clinical samples were studied to establish the methylation patterns of the 19 CpG dinucleotides within the long control region and part of the L1 gene by bisulfite modification, PCR amplification, DNA cloning, and sequencing. We observed major heterogeneities between clones from different samples as well as between clones from individual samples. The methylation frequency of CpGs was measured at 14.5%. In addition, 0.21 and 0.23%, respectively, of the CpA and CpT sites, indicators of de novo methylation, were methylated. Methylation frequencies exceeded 30% in the CpGs overlapping with the L1 gene and were about 10% for most other positions. A CpG site located in the linker between two nucleosomes positioned over the enhancer and promoter of HPV-16 had minimal methylation. This region forms part of the HPV replication origin and is close to binding sites of master-regulators of transcription during epithelial differentiation. Methylation of most sites was highest in carcinomas, possibly due to tandem repetition and chromosomal integration of HPV-16 DNA. Methylation was lowest in dysplasia, likely reflecting the transcriptional activity in these infections. Our data document the efficient targeting of HPV genomes by the epithelial methylation machinery, possibly as a cellular defense mechanism, and suggest involvement of methylation in HPV oncogene expression and the early-late switch.

scholarly journals Comparative analysis of DNA methylation patterns in transgenic Drosophila overexpressing mouse DNA methyltransferases

2004 ◽  
Vol 378 (3) ◽  
pp. 763-768 ◽  
Author(s):  
Cora MUND ◽  
Tanja MUSCH ◽  
Martin STRÖDICKE ◽  
Birte ASSMANN ◽  
En LI ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Mammalian Cells ◽  
Cytosine Methylation ◽  
De Novo ◽  
Epigenetic Modification ◽  
Dna Methyltransferases ◽  
Significant Activity ◽  
Cpg Dinucleotides ◽  
Methylation Patterns ◽  
Transgenic Drosophila

DNA methyltransferases (Dnmts) mediate the epigenetic modification of eukaryotic genomes. Mammalian DNA methylation patterns are established and maintained by co-operative interactions among the Dnmt proteins Dnmt1, Dnmt3a and Dnmt3b. Owing to their simultaneous presence in mammalian cells, the activities of individual Dnmt have not yet been determined. This includes a fourth putative Dnmt, namely Dnmt2, which has failed to reveal any activity in previous assays. We have now established transgenic Drosophila strains that allow for individual overexpression of all known mouse Dnmts. Quantitative analysis of genomic cytosine methylation levels demonstrated a robust Dnmt activity for the de novo methyltransferases Dnmt3a and Dnmt3b. In addition, we also detected a weak but significant activity for Dnmt2. Subsequent methylation tract analysis by genomic bisulphite sequencing revealed that Dnmt3 enzymes preferentially methylated CpG dinucleotides in a processive manner, whereas Dnmt2 methylated isolated cytosine residues in a non-CpG dinucleotide context. Our results allow a direct comparison of the activities of mammalian Dnmts and suggest a significant functional specialization of these enzymes.

scholarly journals Structural insights into CpG-specific DNA methylation by human DNA methyltransferase 3B

2020 ◽  
Vol 48 (7) ◽  
pp. 3949-3961 ◽  
Author(s):  
Chien-Chu Lin ◽  
Yi-Ping Chen ◽  
Wei-Zen Yang ◽  
James C K Shen ◽  
Hanna S Yuan
Keyword(s):  
Dna Methylation ◽  
Dna Methyltransferase ◽  
Cytosine Methylation ◽  
Catalytic Domain ◽  
De Novo ◽  
Water Channel ◽  
Dna Methyltransferases ◽  
Structural Basis ◽  
Cpg Sites ◽  
Methylation Patterns

Abstract DNA methyltransferases are primary enzymes for cytosine methylation at CpG sites of epigenetic gene regulation in mammals. De novo methyltransferases DNMT3A and DNMT3B create DNA methylation patterns during development, but how they differentially implement genomic DNA methylation patterns is poorly understood. Here, we report crystal structures of the catalytic domain of human DNMT3B–3L complex, noncovalently bound with and without DNA of different sequences. Human DNMT3B uses two flexible loops to enclose DNA and employs its catalytic loop to flip out the cytosine base. As opposed to DNMT3A, DNMT3B specifically recognizes DNA with CpGpG sites via residues Asn779 and Lys777 in its more stable and well-ordered target recognition domain loop to facilitate processive methylation of tandemly repeated CpG sites. We also identify a proton wire water channel for the final deprotonation step, revealing the complete working mechanism for cytosine methylation by DNMT3B and providing the structural basis for DNMT3B mutation-induced hypomethylation in immunodeficiency, centromere instability and facial anomalies syndrome.

scholarly journals Nurse cell-derived small RNAs define paternal epigenetic inheritance in Arabidopsis

2021 ◽  
Author(s):  
Jincheng Long ◽  
James Walker ◽  
Wenjing She ◽  
Billy Aldridge ◽  
Hongbo Gao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Small Rnas ◽  
Nurse Cell ◽  
De Novo ◽  
Epigenetic Inheritance ◽  
Genome Integrity ◽  
Nurse Cells ◽  
Male Germline ◽  
Methylation Patterns

AbstractThe plant male germline undergoes DNA methylation reprogramming, which methylates genes de novo and thereby alters gene expression and facilitates meiosis. Why reprogramming is limited to the germline and how specific genes are chosen is unknown. Here, we demonstrate that genic methylation in the male germline, from meiocytes to sperm, is established by germline-specific siRNAs transcribed from transposons with imperfect sequence homology. These siRNAs are synthesized by meiocyte nurse cells (tapetum) via activity of the tapetum-specific chromatin remodeler CLASSY3. Remarkably, tapetal siRNAs govern germline methylation throughout the genome, including the inherited methylation patterns in sperm. Finally, we demonstrate that these nurse cell-derived siRNAs (niRNAs) silence germline transposons, thereby safeguarding genome integrity. Our results reveal that tapetal niRNAs are sufficient to reconstitute germline methylation patterns and drive extensive, functional methylation reprogramming analogous to piRNA-mediated reprogramming in animal germlines.

scholarly journals Importance of Genetic Factors in Male Fertility Disorders, Clinical Relevance of Epigenetic Markers in Male Infertility

2019 ◽  
Vol 70 (7) ◽  
pp. 2566-2570
Author(s):  
Dragos Botezatu ◽  
Cristina Popescu ◽  
Andrei-Dan Korodi ◽  
Cristian Furau ◽  
Gheorghe Furau ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Male Infertility ◽  
Male Fertility ◽  
Complex Problem ◽  
The Body ◽  
Control Group ◽  
Global Methylation ◽  
Methylation Of Dna ◽  
Genome Methylation ◽  
Methylation Patterns

Male infertility is a common and complex problem affecting 1 out of 20 men. Despite extensive research in this area, in many cases, the underlying causes are unknown. Epigenetic changes control a series of processes within the body, including male fertility. Classification of infertile men using a more detailed analysis of DNA methylation patterns could reveal a new level of low rates of fertilization, implantation, or pregnancy. In this context, it seemed to us to use the techniques available to evaluate the degree of global methylation of DNA in infertile patients who have modified sperm counts, but also those who apparently do not have a clear cause of infertility. For this we used the Quest 5mC-Zymoresaerch-ELISA kit that can detect within about 5 hours the global level of genome methylation. Claims on which common illnesses have an epigenetic base are still open to speculation, but if true, it can imprint a new direction in medicine. Our data, although from a pilot study, are consistent with those in the literature. A recent study has shown that DNA methylation levels were significantly higher in oligoasthenoteratozoospermia patients than in the control group and the increase in global DNA methylation and histone retention in men with oligoasthenoteratozoospermia.

scholarly journals Intergenerational epigenetic inheritance in reef-building corals

2018 ◽  
Author(s):  
Yi Jin Liew ◽  
Emily J. Howells ◽  
Xin Wang ◽  
Craig T. Michell ◽  
John A. Burt ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Intergenerational Transmission ◽  
Epigenetic Inheritance ◽  
Cpg Methylation ◽  
Epigenetic Mechanisms ◽  
Transgenerational Inheritance ◽  
Genome Wide ◽  
Methylation Patterns ◽  
Hypermethylated Genes

MainThe notion that intergenerational or transgenerational inheritance operates solely through genetic means is slowly being eroded: epigenetic mechanisms have been shown to induce heritable changes in gene activity in plants1,2and metazoans1,3. Inheritance of DNA methylation provides a potential pathway for environmentally induced phenotypes to contribute to evolution of species and populations1–4. However, in basal metazoans, it is unknown whether inheritance of CpG methylation patterns occurs across the genome (as in plants) or as rare exceptions (as in mammals)4. Here, we demonstrate genome-wide intergenerational transmission of CpG methylation patterns from parents to sperm and larvae in a reef-building coral. We also show variation in hypermethylated genes in corals from distinct environments, indicative of responses to variations in temperature and salinity. These findings support a role of DNA methylation in the transgenerational inheritance of traits in corals, which may extend to enhancing their capacity to adapt to climate change.

scholarly journals Persistent epigenetic memory impedes rescue of the telomeric phenotype in human ICF iPSCs following DNMT3B correction

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Shir Toubiana ◽  
Miriam Gagliardi ◽  
Mariarosaria Papa ◽  
Roberta Manco ◽  
Maty Tzukerman ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Dna Methyltransferase ◽  
De Novo ◽  
Pharmacological Intervention ◽  
Icf Syndrome ◽  
Genome Wide ◽  
Mammalian Genomes ◽  
Induced Pluripotent ◽  
Methylation Patterns

DNA methyltransferase 3B (DNMT3B) is the major DNMT that methylates mammalian genomes during early development. Mutations in human DNMT3B disrupt genome-wide DNA methylation patterns and result in ICF syndrome type 1 (ICF1). To study whether normal DNA methylation patterns may be restored in ICF1 cells, we corrected DNMT3B mutations in induced pluripotent stem cells from ICF1 patients. Focusing on repetitive regions, we show that in contrast to pericentromeric repeats, which reacquire normal methylation, the majority of subtelomeres acquire only partial DNA methylation and, accordingly, the ICF1 telomeric phenotype persists. Subtelomeres resistant to de novo methylation were characterized by abnormally high H3K4 trimethylation (H3K4me3), and short-term reduction of H3K4me3 by pharmacological intervention partially restored subtelomeric DNA methylation. These findings demonstrate that the abnormal epigenetic landscape established in ICF1 cells restricts the recruitment of DNMT3B, and suggest that rescue of epigenetic diseases with genome-wide disruptions will demand further manipulation beyond mutation correction.

DNA METHYLATION IN PLANTS

2021 ◽  
pp. 109-114
Author(s):  
Adil Altaf ◽  
Ahmad Zada
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Epigenetic Inheritance ◽  
Plant Tissues ◽  
Developmental Abnormalities ◽  
Process Use ◽  
Model Plant Arabidopsis Thaliana ◽  
Methylation Patterns ◽  
Kinetics Of ◽  
Generation Sequencing

Common DNA methylation controls gene expression and preserves genomic integrity. Mal methylation can cause developmental abnormalities in the plants. Multiple enzymes carrying out de novo methylation, methylation maintenance, and active demethylation culminate in a particular DNA methylation state. Next-generation sequencing advances and computational methods to analyze the data. The model plant Arabidopsis thaliana was used to study DNA methylation patterns, epigenetic inheritance, and plant methylation. Plant DNA methylation research reveals methylation patterns and describing variations in plant tissues. Determining the kinetics of DNA methylation in diverse plant tissues is also a new field. However, it is vital to understand regulatory and developmental decisions and use plant model species to develop new commercial crops; that are more resistant to stress and yield more. There are several methods available for assessing DNA methylation data. The performance of several techniques is assessed in A. thaliana, which has a smaller genome than hexaploid bread wheat. Keywords: DNA methylation, plants, process, use and benefits

scholarly journals Reading the unique DNA methylation landscape of the brain: Non-CpG methylation, hydroxymethylation, and MeCP2

2015 ◽  
Vol 112 (22) ◽  
pp. 6800-6806 ◽  
Author(s):  
Benyam Kinde ◽  
Harrison W. Gabel ◽  
Caitlin S. Gilbert ◽  
Eric C. Griffith ◽  
Michael E. Greenberg
Keyword(s):  
Dna Methylation ◽  
Binding Protein ◽  
Cell Types ◽  
Cpg Methylation ◽  
Early Postnatal Development ◽  
Cpg Dinucleotides ◽  
Epigenetic Regulator ◽  
And Function ◽  
Syndrome Protein ◽  
The Brain

DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.

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