DNA methylation and histone modifications induced by abiotic stressors in plants

2021 ◽  
Author(s):  
Karolina Czajka ◽  
Melanie Mehes-Smith ◽  
Kabwe Nkongolo
Author(s):  
Irfete S. Fetahu ◽  
Sabine Taschner-Mandl

AbstractNeuroblastoma (NB) is a pediatric cancer of the sympathetic nervous system and one of the most common solid tumors in infancy. Amplification of MYCN, copy number alterations, numerical and segmental chromosomal aberrations, mutations, and rearrangements on a handful of genes, such as ALK, ATRX, TP53, RAS/MAPK pathway genes, and TERT, are attributed as underlying causes that give rise to NB. However, the heterogeneous nature of the disease—along with the relative paucity of recurrent somatic mutations—reinforces the need to understand the interplay of genetic factors and epigenetic alterations in the context of NB. Epigenetic mechanisms tightly control gene expression, embryogenesis, imprinting, chromosomal stability, and tumorigenesis, thereby playing a pivotal role in physio- and pathological settings. The main epigenetic alterations include aberrant DNA methylation, disrupted patterns of posttranslational histone modifications, alterations in chromatin composition and/or architecture, and aberrant expression of non-coding RNAs. DNA methylation and demethylation are mediated by DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) proteins, respectively, while histone modifications are coordinated by histone acetyltransferases and deacetylases (HATs, HDACs), and histone methyltransferases and demethylases (HMTs, HDMs). This article focuses predominately on the crosstalk between the epigenome and NB, and the implications it has on disease diagnosis and treatment.


2007 ◽  
Vol 21 (5) ◽  
pp. 1205-1215 ◽  
Author(s):  
Xuegong Zhu ◽  
Sylvia L. Asa ◽  
Shereen Ezzat

Abstract The transcription factor Ikaros (Ik) is at the center of a functionally diverse chromatin-remodeling network that is critical for the development and regulation of both the immune and endocrine systems. Dominant negative forms of Ik result in neoplastic growth in mouse genetic studies and have been identified in human tumors. Ik modulates chromatin accessibility through associations with members of the NURD complex including histone deacetylase complexes. We show here that Ik expression in mouse pituitary corticotroph cells is itself regulated through histone modifications as well as DNA methylation. Examination of primary human pituitary specimens also identified a correlation of loss of Ik expression with the presence of DNA methylation in the untranslated exon 1 CpG island. These findings have important implications for the understanding of Ikaros’ role in epigenetic functions and suggest a potential role for demethylating agents in the treatment of related disorders.


2016 ◽  
Vol 311 (6) ◽  
pp. L1245-L1258 ◽  
Author(s):  
Isaac K. Sundar ◽  
Irfan Rahman

Chromatin-modifying enzymes mediate DNA methylation and histone modifications on recruitment to specific target gene loci in response to various stimuli. The key enzymes that regulate chromatin accessibility for maintenance of modifications in DNA and histones, and for modulation of gene expression patterns in response to cigarette smoke (CS), are not known. We hypothesize that CS exposure alters the gene expression patterns of chromatin-modifying enzymes, which then affects multiple downstream pathways involved in the response to CS. We have, therefore, analyzed chromatin-modifying enzyme profiles and validated by quantitative real-time PCR (qPCR). We also performed immunoblot analysis of targeted histone marks in C57BL/6J mice exposed to acute and subchronic CS, and of lungs from nonsmokers, smokers, and patients with chronic obstructive pulmonary disease (COPD). We found a significant increase in expression of several chromatin modification enzymes, including DNA methyltransferases, histone acetyltransferases, histone methyltransferases, and SET domain proteins, histone kinases, and ubiquitinases. Our qPCR validation data revealed a significant downregulation of Dnmt1, Dnmt3a, Dnmt3b, Hdac2, Hdac4, Hat1, Prmt1, and Aurkb. We identified targeted chromatin histone marks (H3K56ac and H4K12ac), which are induced by CS. Thus CS-induced genotoxic stress differentially affects the expression of epigenetic modulators that regulate transcription of target genes via DNA methylation and site-specific histone modifications. This may have implications in devising epigenetic-based therapies for COPD and lung cancer.


PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e30515 ◽  
Author(s):  
Andriy Bilichak ◽  
Yaroslav Ilnystkyy ◽  
Jens Hollunder ◽  
Igor Kovalchuk

2018 ◽  
Vol 50 (4) ◽  
pp. 1376-1397 ◽  
Author(s):  
Yanhui Zhai ◽  
Zhiren Zhang ◽  
Hao Yu ◽  
Li Su ◽  
Gang Yao ◽  
...  

Background/Aims: DNA methylation and histone modifications are essential epigenetic marks that can significantly affect the mammalian somatic cell nuclear transfer (SCNT) embryo development. However, the mechanisms by which the DNA methylation affects the epigenetic reprogramming have not been fully elucidated. Methods: In our study, we used quantitative polymerase chain reaction (qPCR), Western blotting, immunofluorescence staining (IF) and sodium bisulfite genomic sequencing to examine the effects of RG108, a DNA methyltransferase inhibitor (DNMTi), on the dynamic pattern of DNA methylation and histone modifications in porcine SCNT embryos and investigate the mechanism by which the epigenome status of donor cells’ affects SCNT embryos development and the crosstalk between epigenetic signals. Results: Our results showed that active DNA demethylation was enhanced by the significantly improving expression levels of TET1, TET2, TET3 and 5hmC, and passive DNA demethylation was promoted by the remarkably inhibitory expression levels of DNMT1, DNMT3A and 5mC in embryos constructed from the fetal fibroblasts (FFs) treated with RG108 (RG-SCNT embryos) compared to the levels in embryos from control FFs (FF-SCNT embryos). The signal intensity of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 9 acetylation (H3K9Ac) was significantly increased and the expression levels of H3K4 methyltransferases were more than 2-fold higher expression in RG-SCNT embryos. RG-SCNT embryos had significantly higher cleavage and blastocyst rates (69.3±1.4%, and 24.72±2.3%, respectively) than FF-SCNT embryos (60.1±2.4% and 18.38±1.9%, respectively). Conclusion: Dynamic changes in DNA methylation caused by RG108 result in dynamic alterations in the patterns of H3K4me3, H3K9Ac and histone H3 lysine 9 trimethylation (H3K9me3), which leads to the activation of embryonic genome and epigenetic modification enzymes associated with H3K4 methylation, and contributes to reconstructing normal epigenetic modifications and improving the developmental efficiency of porcine SCNT embryos.


PLoS Genetics ◽  
2011 ◽  
Vol 7 (8) ◽  
pp. e1002243 ◽  
Author(s):  
Wei Li ◽  
Hui Liu ◽  
Zhi Juan Cheng ◽  
Ying Hua Su ◽  
Hua Nan Han ◽  
...  

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