Histone-H3 Protein, Xenopus laevis

Histone H3 is an essential component of the nucleosome and plays a key role in the complex process of packaging and compacting DNA into chromatin, which in turn restricts access to DNA to cellular machinery that requires DNA as a template. This histone and its counterparts play critical roles in key cellular functions, including transcriptional regulation, DNA repair, DNA replication, and maintenance of chromosomal stability. Regulation of DNA accessibility involves a complex interplay of post-translational modifications, collectively known as the histone code, and dynamic remodeling of the nucleosome. The nucleosome itself comprises a histone octamer, composed of two molecules each of H2A, H2B, H3, and H4, assembled into one H3-H4 heterotetramer and two H2A-H2B heterodimers. This octamer efficiently packages approximately 147 base pairs of DNA, demonstrating its indispensable role in organizing chromatin structure and facilitating key genomic processes. In addition, histone H3 interacts with various cellular components, such as TONSL, CHAF1A, CHAF1B, MCM2, and DNAJC9, further contributing to its multifaceted functions.