Histone H2Av

The nucleosome is the smallest subunit of chromatin and consists of 147 DNA base pairs wrapped around the core histone octamer (histone H2A, histone H2B, histone H3, and histone H4). Histone H2A.Z (H2AZ, H2AFZ) is a variant of histone H2A, a protein similar to classic H2A, but with a different molecular identity and unique functions. H2A.Z is highly conserved during evolution. It plays an important role in basic cellular mechanisms such as gene activation, chromosome segregation, heterochromatin silencing, and cell cycle progression. In Drosophila, the H2A variant corresponding to H2AZ is H2Av. H2Av is an essential protein in Drosophila and is involved in the activation and inhibition of transcription. H2Av is located in the centromeric heterochromatin in Drosophila, and the level of heterochromatin in the centromere of Drosophila lacking H2Av is reduced. However, the distribution of H2Av nucleosomes throughout the rest of the Drosophila genome is related to genes with an open and uniform chromatin structure in the promoter region.