Histone H3 is a 17 kD nuclear protein that is a component of an octamer containing pairs of each of four core histones (H2A, H2B, H3, H4). The core histones create nucleosome structure of chromosomal fiber in eukaryotes and are dynamic in gene regulation. The histones exhibit cell cycle-dependent transcriptional regulation except for the variant H3.3 which is cell cycle-independent. Histone H3 can be modified by phosphorylation, acetylation, ubiquitination, ribosylation, and methylation. Histone H3 has been shown to interact with Rsk-2, MSK1, GCN5 family of HATs, HDACs, PARP, SET7/9, and CARM1. The Poly6019 antibody has been shown to be useful for Western blotting of human and mouse histone H3.