Chemical “Diversity” of Chromatin Through Histone Variants and Histone Modifications

Abstract

The eukaryotic genome is highly complex and compartmentalized into distinct physical and functional domains. Although the majority of genomic DNA is wrapped around histone proteins in the same manner to form repeating units of nucleosomes, the use of distinct histone variants and the myriad of posttranslational modifications (PTMs) on different histones and amino acid residues create great diversity among these nucleosomes. In this review, we summarize some of the most recent findings in the histone variant and PTM fields and update the readers on our current understanding of various histone-related pathways. Furthermore, we discuss how homotypic or heterotypic deposition of histone variants as well as symmetric or asymmetric histone PTMs within the nucleosome context can further expand the diversity and functionality of chromatin. Altogether, this review highlights the complexity of chromatin composition and organization and their regulatory functions within the eukaryotic genome.

Study on the Expression Differences and the Correlation with H2BE Gene of Th Related Cytokines in SSDHS and LDSDS TCM-Syndromes of CHB Patients

“…Histone is involved in many cellular processes such as transcriptional regulation, DNA replication, RNA splicing, etc., since the DNA is wrapped and interacts directly with histone proteins [ 28 ]. However, at present, a myriad of studies on histone mainly focus on histone modification, such as methylation, acetylation, phosphorylation, etc., rather than the effects generated by expression level changes [ 18 , 29 ].…”

“…In addition, the results also demonstrated that almost all the cytokines were expressed much higher in LDSDS than in SSDHS, and this suggested that the immune response may be more intense in LDSDS than in SSDHS, and this result was also consistent with Lu et al (2019) [11]. Histone is involved in many cellular processes such as transcriptional regulation, DNA replication, RNA splicing, etc., since the DNA is wrapped and interacts directly with histone proteins [28]. However, at present, a myriad of studies on histone mainly focus on histone modification, such as methylation, acetylation, phosphorylation, etc., rather than the effects generated by expression level changes [18,29].…”

Transgenerational inheritance of metabolic disease

“…Importantly, although many epigenetic marks were largely considered absent in human sperm, many nucleosomes remain associated with chromatin in sperm and DNA methylation not only remains present at specific loci, but is hypermethylated at many loci relative to later embryonic stages [29,30]. Of note, it is unlikely that all epigenetic marks have been discovered, as highlighted by the recent identifications of many novel histone marks including lysine crotonylation and glutamine methylation [31]. In addition to the epigenetic marks, germ cells carry RNA molecules such as mRNAs, miRNA, and piRNAs, as well as metabolites and proteins that may be important for mediating transgenerational inheritance.…”