A basic unit of chromatin is the nucleosome, which is organized as ∼150bp DNA wrapped around a histone octamer made from two of each core histone family, H2A, H2B, H3, and H4 [1,2].

This variant has a Lastly, MacroH2A variant is a variant that is similar to H2A; it is encoded by the The structure of macroH2A variant was exposed through DNA Folding: The histone H2A variant H2A.Z is highly conserved among eukaryotes and is of particular interest because it has an essential, yet unknown role in early development. Histone H2A. The histone variant H2A.Z is involved in several processes such as transcriptional control, DNA repair, regulation of centromeric heterochromatin and, not surprisingly, is implicated in diseases such as cancer. Histone H2A is composed of non-allelic variants. H2A has been correlated with DNA modification and Antimicrobial peptide: Here, we review the recent developments on H2A.Z focusing on its role in transcriptional … How histone variants such as H2AZ are incorporated into nucleosomes has been obscure. In addition, we have identified a new H2A variant class, present only in non-flowering land plants, that may repre-sent an ancestor of H2A.W.

Histone H2A has several variants, and changes in chromatin composition associated with their replacement might involve chromatin structure remodeling. Histone H2A Variants The universal H2A variants H2A.X and H2A.Z are found in almost all organisms (Talbert and Henikoff, 2010) . activities. Histone tail lysines were labeled. H2AZ C-terminal lysines were absent in the illustration and G119 residue was marked. This was observed in differentiating neurons during synthesis and turnover; changes in variant composition were seen among the H2A.1 histone. In vertebrates and invertebrates, Histone H2A variant is reported to be involved in host immune response by acting as antimicrobial peptides (AMPs). Zoomed illustration of the N-terminus and C-terminus of H2A variants. The most divergent class is the designated “short H2A variants” (H2A.B, H2A.L, H2A.P and H2A.Q), so termed because they lack a H2A C-terminal tail. Since H2A packages DNA molecules into chromatin, the packaging process will affect gene expression.

It has been shown that histone variant H2A.Z, which is enriched at the +1 nucleosome in eukaryotes , can lower the barrier to Pol II .
DNA damage or heat shock response. Notable variants include H2A.1, H2A.2, H2A.X, and H2A.Z. However, modification of H2A does occur. Eukaryotic genomes are compacted into chromatin, consisting of histone proteins and DNA.
H2A variants can be explored using "HistoneDB with Variants" database These histone variants appeared late in evolution in eutherian mammals and are lineage-specific, being expressed in the testis (and, in the case of H2A.B, also in the brain). These are coded by 26 genes with majority of them present in cluster 1 and 2 and a single gene in cluster 3. Out of these, 9 genes are not part of any cluster and code for atypical histone H2A such as macro-H2A, H2A-Bbd etc.Macro-H2A is a bulky variant with 327 amino acid and ~40 kDa compared to the normal 14 kDa weight. d Electrostatic potential (red-negative, blue-positive) analyses of H2A variant-containing nucleosomes. Interestingly, atypical variants such as MacroH2As, H2A.X, H2A-Bbd, differ considerably in size.

The only variant that remained constant in the neural differentiation was variant H2AZ.Physically, there are small changes on the surface area of the nucleosome that make the histone differ from H2A. We have found that Swr1, a Swi2/Snf2-related adenosine triphosphatase, is the catalytic core of a multisubunit, histone-variant exchanger that efficiently replaces conventional histone H2A with histone H2AZ in nucleosome arrays.