H2B is one of five highly conserved classes of proteins identified as histones. Located in the nuclei of eukaryotic cells, histones are closely associated with DNA. The proteins, all but one of which is comprised of 100 to 150 residues, function in the formation of nucleosomes, chromatin structure regulation, and gene regulation. The digital video sequences presented in this section visualize the dynamic interactions between fluorescently labeled red H2B histones (mApple) and green C-Src (mEmerald).