H3F3A Human

Histones are essential nuclear proteins that play a critical role in the organization and regulation of chromatin structure in eukaryotic cells. Among the various histone proteins, the H3 histone family is particularly significant due to its involvement in the formation of nucleosomes, which are the fundamental units of chromatin. The H3 histone family includes several variants, one of which is H3.3, encoded by the H3F3A and H3F3B genes .

H3.3 is a replication-independent histone variant that is expressed throughout the cell cycle, unlike other histones that are primarily expressed during the S phase. This variant is crucial for maintaining genome integrity and is involved in various cellular processes, including transcription regulation, DNA repair, and chromatin remodeling .

The H3F3A gene, located on chromosome 1q42.12, encodes the H3.3A protein. This gene is one of the two genes responsible for producing the H3.3 variant, the other being H3F3B . The proteins encoded by these genes are identical, although their nucleotide sequences and regulatory elements differ .

The H3.3A protein consists of 135 amino acids and has a molecular weight of approximately 17.7 kDa . It features a long N-terminal tail and a globular domain, which are characteristic of histone proteins. The N-terminal tail undergoes various post-translational modifications, such as methylation, acetylation, and phosphorylation, which influence chromatin structure and gene expression .

H3.3A is incorporated into chromatin independently of DNA replication and is often found in regions of active transcription. It is enriched in covalent modifications associated with gene activation, making it a key player in the regulation of gene expression .

Recombinant H3.3A proteins are produced using various expression systems, such as E. coli, to facilitate research and therapeutic applications. These recombinant proteins are often tagged with His-tags to aid in purification and detection . They are used in studies related to chromatin dynamics, epigenetics, and the development of novel therapeutic strategies.

The study of H3.3A and its role in chromatin biology has significant implications for understanding various biological processes and diseases. Research on H3.3A has provided insights into the mechanisms of gene regulation, the maintenance of genome stability, and the development of certain cancers . Recombinant H3.3A proteins are valuable tools in these research endeavors, enabling scientists to dissect the molecular functions of this histone variant.