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Role of Histone Methyltransferase in Breast Cancer
Published in Meenu Gupta, Rachna Jain, Arun Solanki, Fadi Al-Turjman, Cancer Prediction for Industrial IoT 4.0: A Machine Learning Perspective, 2021
Surekha Manhas, Zaved Ahmed Khan
During DNA packaging, basic proteins – histones – play a reported mark as a chromatin component in the nucleus of eukaryote cells, where they bind with DNA and further proceed the DNA for packaging into smaller units designated as nucleosomes that display their role in gene regulation. The unwounded chromosomal DNA length varies. Diploid cell DNA of humans is about 1.8 meters, shows wounded association on the basic proteins, and has approximately 0.09 mm (90 micrometers) of chromatin. During the mitotic process, the human diploid cell undergoes condensation and duplication, resulting in about 120 mm of chromosome. Histone modifications are directly correlated with gene regulation functions, including ADP-ribosylation, methylation, acetylation, ubiquitination, and citrullination.
Genes and Genomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
Chromatin is the complex combination of DNA, RNA, and protein that makes up chromosomes. It is found inside the nuclei in eukaryotic cells, and within the nucleoid in prokaryotic cells. It is divided between heterochromatin (condensed) and euchromatin (extended) forms. The major components of chromatin are DNA and histone proteins, although many other chromosomal proteins have prominent roles too. The functions of chromatin are to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression and DNA replication. Chromatin contains genetic material instructions to direct cell functions. Changes in chromatin structure are affected by chemical modifications of histone proteins such as methylation (DNA and proteins) and acetylation (proteins), and by non-histone DNA-binding proteins.
Enzyme Kinetics and Drugs as Enzyme Inhibitors
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
A variety of regulatory pathways are involved in epigenetic gene regulation among them DNA methylation, introduction of histone variants, and post-translational modification of histone proteins; long non-coding RNAs (lncRNAs) play essential roles in diverse cellular processes such as chromatin remodeling, transcription, post-transcriptional processing and intracellular trafficking (Cao, 2014). Histone proteins can be modified at specific amino acid residues by diverse chemical moieties including methylation, acetylation, phosphorylation, ubiquitination, and SUMOylation which influences the degree of packaging and thereby the gene activity. Enzymes catalyzing these posttranslational modifications are known as chromatin “writers.” Other proteins such as BET-proteins (bromodomain and extraterminal motif proteins) recognize these modifications and are termed chromatin “readers,” whereas chromatin “erasers” catalyze the removal of histone modifications.
Adverse health effects and stresses on offspring due to paternal exposure to harmful substances
Published in Critical Reviews in Environmental Science and Technology, 2023
Jiaqi Sun, Miaomiao Teng, Fengchang Wu, Xiaoli Zhao, Yunxia Li, Lihui Zhao, Wentian Zhao, Keng Po Lai, Kenneth Mei Yee Leung, John P. Giesy
The third epigenetic mechanism is through modifications of histones. Modifications of histones in mammals are the process of methylation, phosphorylation, acetylation, ubiquitination, adenylate or adenosine diphosphate (ADP) ribosylation of histones, mediated by enzymes (van de Werken et al., 2014). These chemical modifications affect the transcriptional activities of associated genes. The results of current studies suggest that most histones in mammalian sperm are replaced by protamine (Jones, 2012). However, genes that are essential for embryonic development in sperm, such as imprinted genes, miRNA genes and Hox genes, are retained at histone sites in chromatin regions, and these retained histone sites and associated genes can be modified and regulated by methylation and acetylation, thereby affecting the embryonic development of future generations (Hammoud et al., 2009).
Epigenotoxicity: a danger to the future life
Published in Journal of Environmental Science and Health, Part A, 2023
Farzaneh Kefayati, Atoosa Karimi Babaahmadi, Taraneh Mousavi, Mahshid Hodjat, Mohammad Abdollahi
Genetic diversity, environmental effects, and epigenetic factors may bring about autoimmune diseases. Enzymes involved in the histone modification process can impair DNA repair processes. Some HDAC inhibitors (HDACi) increase the possibility of transcription of specific genes such as those involved in autoimmune diseases. These enzymes are more active in T cells and cause post-translational changes. Such changes eventually lead to the immune tolerance modulation and autoimmune diseases. lncRNAs control the expression of genes involved in the differentiation of immune cell types. Also, dysregulation of miRNAs was linked with the incidence of many autoimmune diseases by altering epigenetic mechanisms like DNA methylation, RNA-dependent mechanisms, and post-translational histone modifications.[90] Many chemical agents in the environment, such as various types of hydrocarbons, heavy metals, and agricultural chemicals that have already been addressed, are immunotoxic and cause structural, functional, or combined changes in various immune system components and alter the immune response.[176]
Direct and cost-effective method for histone isolation from cultured mammalian cells
Published in Preparative Biochemistry & Biotechnology, 2023
Anja Batel, Mirjana Polović, Mateo Glumac, Andrea Gelemanović, Matilda Šprung, Ivana Marinović Terzić
Histones are essential for packing the DNA into chromatin structures. They are important for the regulation of gene expression, DNA replication, and DNA damage response. Therefore, studying histones and histone modifications is a key element in researching the above-mentioned cellular processes. Available published methods for histone isolation are suitable for some, but not all required downstream applications. For example, studying epigenetic changes requires a protocol that preserves modifications on histone tails. Therefore, harsh conditions for histone isolation are not suited for such downstream applications. Similarly, studying the changes in histone composition and modifications induced after DNA damage response requires fast isolation protocol and gentle buffer composition. Common techniques for histone isolation use acid or high salt buffer composition for extraction of histones from chromatin.