scholarly journals Genes of the month: H3.3 histone genes: H3F3A and H3F3B

2021 ◽  
pp. jclinpath-2021-207857
Author(s):  
Vishnu Chandra Kumar ◽  
Rekha Pai
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Developmental Disorders ◽  
Methylation Status ◽  
Regulation Of Gene Expression ◽  
Histone Genes ◽  
Histone Tails ◽  
Post Translational Modifications ◽  
Altered Gene ◽  
Methylation Patterns

Histones constitute the chief protein component of DNA. They help to maintain chromatin structure and regulate gene expression. The long double-stranded DNA molecule winds around histone octamers to form nucleosomes which serve the purpose of compacting DNA within the confines of the nuclear membrane. There are five major types of histones, namely H1/H5, H2, H3 and H4. H3.3 is a subtype of H3 histone and can be encoded either by the H3F3A or H3F3B genes independently. Amino acids such as lysine and arginine found in the histone tails are sites of post-translational modifications (PTMs) such as methylation and acetylation. These PTMs in histones are involved in the regulation of gene expression by chromatin remodelling and by controlling DNA methylation patterns. Mutations in histone genes can affect sites of PTMs causing changes in local and global DNA methylation status. These effects are directly linked to neoplastic transformation by altered gene expression. Recurrent H3.3 histone mutations are increasingly identified in several malignancies and developmental disorders. The following review attempts to shed light on the diseases associated with H3.3 histone mutations.

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

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.

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 The Methylation Status of the Epigenome: Its Emerging Role in the Regulation of Tumor Angiogenesis and Tumor Growth, and Potential for Drug Targeting

Cancers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 268 ◽  
Author(s):  
Luciano Pirola ◽  
Oskar Ciesielski ◽  
Aneta Balcerczyk
Keyword(s):  
Dna Methylation ◽  
Tumor Growth ◽  
Tumor Angiogenesis ◽  
Methylation Status ◽  
Angiogenesis Inhibitors ◽  
Post Translational Modifications ◽  
Methylation Patterns ◽  
Cancerous Cells ◽  
Transcriptional State

Approximately 50 years ago, Judah Folkman raised the concept of inhibiting tumor angiogenesis for treating solid tumors. The development of anti-angiogenic drugs would decrease or even arrest tumor growth by restricting the delivery of oxygen and nutrient supplies, while at the same time display minimal toxic side effects to healthy tissues. Bevacizumab (Avastin)—a humanized monoclonal anti VEGF-A antibody—is now used as anti-angiogenic drug in several forms of cancers, yet with variable results. Recent years brought significant progresses in our understanding of the role of chromatin remodeling and epigenetic mechanisms in the regulation of angiogenesis and tumorigenesis. Many inhibitors of DNA methylation as well as of histone methylation, have been successfully tested in preclinical studies and some are currently undergoing evaluation in phase I, II or III clinical trials, either as cytostatic molecules—reducing the proliferation of cancerous cells—or as tumor angiogenesis inhibitors. In this review, we will focus on the methylation status of the vascular epigenome, based on the genomic DNA methylation patterns with DNA methylation being mainly transcriptionally repressive, and lysine/arginine histone post-translational modifications which either promote or repress the chromatin transcriptional state. Finally, we discuss the potential use of “epidrugs” in efficient control of tumor growth and tumor angiogenesis.

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 Decoupling of DNA Methylation Status and Gene Expression Levels in Aging Individuals

2018 ◽  
Vol 4 (2) ◽  
pp. 100040 ◽  
Author(s):  
Anna Wierczeiko ◽  
David Fournier ◽  
Hristo Todorov ◽  
Susanne Klingenberg ◽  
Kristina Endres ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Methylation Status ◽  
Cpg Islands ◽  
Age Groups ◽  
Epigenetic Factors ◽  
Promoter Regions ◽  
Methylation Patterns ◽  
The Impact ◽  
Gene Expression Levels

Aging is a multi-factorial process, where epigenetic factors play one of the major roles in declines of gene expression and organic function. DNA methylation at CpG islands of promoters can directly change the expression of the neighbouring gene mostly through inhibition. Furthermore, it is known that DNA methylation patterns change during aging In our study, we investigated gene regulation through DNA methylation of genes up- and downregulated in long-lived people compared to a younger cohort. Our data revealed that comparatively highly methylated genes were associated with high expression in long-lived people (e.g. over 85). Genes with lower levels of methylation were associated with low expression. These findings might contradict the general model used to associate methylation status with expression. Indeed, we found that methylation in the promoter regions of all investigated genes is rather constant across different age groups, meaning that the disparity between methylation and expression only happens in older people. A potential explanation could be the impact of other epigenetic mechanisms, possibly related to stress.

scholarly journals DNA Methylation, Epigenetics, and Evolution in Vertebrates: Facts and Challenges

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Annalisa Varriale
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Environmental Influence ◽  
Epigenetic Modification ◽  
Regulation Of Gene Expression ◽  
Entire Genome ◽  
Phenotypic Differences ◽  
Methylation Patterns ◽  
And Control

DNA methylation is a key epigenetic modification in the vertebrate genomes known to be involved in biological processes such as regulation of gene expression, DNA structure and control of transposable elements. Despite increasing knowledge about DNA methylation, we still lack a complete understanding of its specific functions and correlation with environment and gene expression in diverse organisms. To understand how global DNA methylation levels changed under environmental influence during vertebrate evolution, we analyzed its distribution pattern along the whole genome in mammals, reptiles and fishes showing that it is correlated with temperature, independently on phylogenetic inheritance. Other studies in mammals and plants have evidenced that environmental stimuli can promote epigenetic changes that, in turn, might generate localized changes in DNA sequence resulting in phenotypic effects. All these observations suggest that environment can affect the epigenome of vertebrates by generating hugely different methylation patterns that could, possibly, reflect in phenotypic differences. We are at the first steps towards the understanding of mechanisms that underlie the role of environment in molding the entire genome over evolutionary times. The next challenge will be to map similarities and differences of DNA methylation in vertebrates and to associate them with environmental adaptation and evolution.

scholarly journals Early-life DNA methylation profiles are indicative of age-related transcriptome changes

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Niran Hadad ◽  
Dustin R. Masser ◽  
Laura Blanco-Berdugo ◽  
David R. Stanford ◽  
Willard M. Freeman
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Early Life ◽  
Brain Aging ◽  
Epigenetic Modification ◽  
Age Related ◽  
Developmental Origins Of Disease ◽  
Altered Gene ◽  
Methylation Patterns ◽  
Relationship Of

Abstract Background Alterations to cellular and molecular programs with brain aging result in cognitive impairment and susceptibility to neurodegenerative disease. Changes in DNA methylation patterns, an epigenetic modification required for various CNS functions are observed with brain aging and can be prevented by anti-aging interventions, but the relationship of altered methylation to gene expression is poorly understood. Results Paired analysis of the hippocampal methylome and transcriptome with aging of male and female mice demonstrates that age-related differences in methylation and gene expression are anti-correlated within gene bodies and enhancers. Altered promoter methylation with aging was found to be generally un-related to altered gene expression. A more striking relationship was found between methylation levels at young age and differential gene expression with aging. Highly methylated gene bodies and promoters in early life were associated with age-related increases in gene expression even in the absence of significant methylation changes with aging. As well, low levels of methylation in early life were correlated to decreased expression with aging. This relationship was also observed in genes altered in two mouse Alzheimer’s models. Conclusion DNA methylation patterns established in youth, in combination with other epigenetic marks, were able to accurately predict changes in transcript trajectories with aging. These findings are consistent with the developmental origins of disease hypothesis and indicate that epigenetic variability in early life may explain differences in aging trajectories and age-related disease.

Maternal exposure to a mitochondrial toxicant results in life-long alterations in DNA methylation and gene expression in the offspring

2019 ◽  
Author(s):  
Oswaldo A. Lozoya ◽  
Fuhua Xu ◽  
Dagoberto Grenet ◽  
Tianyuan Wang ◽  
Sara A. Grimm ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Mitochondrial Dysfunction ◽  
Coat Color ◽  
Methylation Status ◽  
Maternal Exposure ◽  
Antioxidant Defenses ◽  
Epigenetic Remodeling ◽  
Altered Gene ◽  
Long Term Impact

AbstractMitochondrial-driven alterations of the epigenome have been reported but whether they are relevant at the organismal level remain unknown. The viable yellow agouti mouse (Avy) is a powerful epigenetic biosensor model that reports on the DNA methylation status of the Avy locus through the coat color of the animals. Here we show that maternal exposure to rotenone, a potent mitochondrial complex I inhibitor, changes the DNA methylation status of the Avy locus and broadly affects the liver DNA methylome of the offspring. These effects were accompanied by altered gene expression programs that persisted throughout life. Mitochondrial dysfunction was present in the mothers but not in the offspring until 12 months of age, when electron transport and antioxidant defenses were impaired. These results highlight a putative novel role for mitochondria in nuclear epigenetic remodeling during development, raising fundamental questions about the long-term impact of mitochondrial dysfunction to health and disease.

scholarly journals Epigenetic Changes During Mechanically Induced Osteogenic Lineage Commitment

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Julia C. Chen ◽  
Mardonn Chua ◽  
Raymond B. Bellon ◽  
Christopher R. Jacobs
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Shear Stress ◽  
Fluid Shear Stress ◽  
Methylation Status ◽  
Lineage Commitment ◽  
Fluid Shear ◽  
Osteogenic Lineage ◽  
Osteogenic Markers ◽  
Heterochromatin Structure

Osteogenic lineage commitment is often evaluated by analyzing gene expression. However, many genes are transiently expressed during differentiation. The availability of genes for expression is influenced by epigenetic state, which affects the heterochromatin structure. DNA methylation, a form of epigenetic regulation, is stable and heritable. Therefore, analyzing methylation status may be less temporally dependent and more informative for evaluating lineage commitment. Here we analyzed the effect of mechanical stimulation on osteogenic differentiation by applying fluid shear stress for 24 hr to osteocytes and then applying the osteocyte-conditioned medium (CM) to progenitor cells. We analyzed gene expression and changes in DNA methylation after 24 hr of exposure to the CM using quantitative real-time polymerase chain reaction and bisulfite sequencing. With fluid shear stress stimulation, methylation decreased for both adipogenic and osteogenic markers, which typically increases availability of genes for expression. After only 24 hr of exposure to CM, we also observed increases in expression of later osteogenic markers that are typically observed to increase after seven days or more with biochemical induction. However, we observed a decrease or no change in early osteogenic markers and decreases in adipogenic gene expression. Treatment of a demethylating agent produced an increase in all genes. The results indicate that fluid shear stress stimulation rapidly promotes the availability of genes for expression, but also specifically increases gene expression of later osteogenic markers.

scholarly journals DNA methylation and regulation of gene expression: Guardian of our health

The Nucleus ◽  
2021 ◽  
Author(s):  
Gaurab Aditya Dhar ◽  
Shagnik Saha ◽  
Parama Mitra ◽  
Ronita Nag Chaudhuri
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Regulation Of Gene Expression
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