Histone

1.3 Histone variants Histone variants are non-allelic isoforms of core histones that have specialized functions resulting from its distinct amino acid constitution. All histone families except for H4 histone have variant forms (Kamakaka and Biggins, 2005). Unlike core histones, which are only expressed during S phase, histone variants are continuously expressed throughout the cell cycle and incorporated into DNA in a replication-independent manner (Sansoni et al., 2014). A great number of histone variants have been discovered and well studied to date, as illustrated in Table 1. CenH3 is a ubiquitously expressed variant, which is enriched at the centromeric region. It is essential for chromosome stability and accurate chromosome segregation…

Sirtuins and Histone deactylases (HDACs) Eukaryotic DNA is packed in a high level structure called chromatin, resulting from the assembly of an elementary unit, the nucleosome, and an octameric structure obtained from eight proteins called histones [1]. Histone deacetylation is a reversible process whereby histone and non-histone protein transfer the acetyl moiety from acetyl co-enzyme A (CoA) to lysines while histone acetylation is the direct opposite process whereby acetyl groups are removed…

There are many mechanisms of epigenetics, including such as de/acetylation and methylation of histones, hyper methylation of CpG islands and phosphorylation etc. Epigenetics can be both spontaneous and hereditary, with some forms of epigenetics, such as histone acetylation, being passed on through gametes. Some forms of epigenetics have large consequences, leading to some serious conditions e.g. Prader-Willi syndrome, whilst some can have longer term ramifications for future generations e.g.…

DNA methylation is a process in which methylations in a gene’s promoter region cause silencing of the gene [SCHROEDER]. Moreover, histone modification is the process in which a histone protein is modified through acetylation, methylation, or phosphorylation, and these chemical reactions influence gene expression [SCHROEDER]. Current studies emphasize the role of these mechanisms in psychological disorders such as anxiety and major depressive disorder [SCHROEDER]. For instance, a study observed…

Chromatin is a compacted form of chromosomal DNA, the basic unit of which is the nucleosome, consisting of 146 bp of DNA wrapped around a core histone octamer. To regulate the structure of chromatin, histones undergo a large number of post-translational modifications, such as acetylation, methylation, phosphorylation, ubiquitylation, sumoylation, ADP ribosylation, beta-N-acetylglucosamine and deamination. These modifications can also recruit other remodeling proteins and complexes to reposition…

Epigenetic modifications/factors are heritable changes in gene activity and expression that occur without alteration in genomic DNA sequences. Epigenetic changes lead to the modulation of intrinsic gene activates, which are ultimately responsible for protein translation and cellular activities. In B cells, microRNAs are epigenetic factors that modulate the expression of Aicda, which is essential for Ig class switch DNA recombination (CSR) and somatic hypermutation (SHM), and Prdm1, which is…

Epigenetics the study of how cellular mechanisms control gene and how gene expression impacts health and behavior. Bi-directionality how human psychologically develop both by genetic predisposition and by the environment. Epigenesist does not change the genome, but the way cells react to the environment. Epigenome tell genome what to do. Epigenesist is controlled by methyl groups and histones. Methyl groups binds to a gene and tells it to not express it. Methyl groups bind differently to…

Epigenetics is the study of how changes and environmental factors experienced by an organism can affect the way genes are expressed without altering the genetic code. Epigenetics has also been linked to ageing. The reason why epigenetics affects ageing is because the DNA methylation acts as a clamp on the chromosomes, so when it comes time for the cell to replicate and unwind its chromatin from around the histones to copy the DNA, the methylation groups don’t allow that segment of DNA from being…

The study of heritable changes in gene expression without a change in DNA sequence is defined as epigenetics. Epigenetics covers a variety of areas in life science such as, biological sciences, effect of pollutants, etc.. The study of epigenetics is important because it allows researchers to trace the causes of certain diseases, follow the effects pollution has in humans and understand how eating habits can alter a person's appearance. Epigenetic modifications can affect the level of expression…

attentive to their babies, used the findings of Meaney and Szyf as a stepping stone for their own findings. Meaney and Szyf continued on to write dozens of papers on this topic and they dove deeper into finding many important things like the effects of the age traumatic events occur and the epigenetic changes. Epigenetics in the article is described in the book as the process in which something causes certain genes on DNA to express themselves and others to not. In Greek epi is translated to…