Histones are basic nuclear proteins that are responsible for the nucleosome structure of the chromosomal fiber in eukaryotes. Histones H1 is the most variable histone and its role at the epigenetic level is less characterized than that of core histones. The lysine-rich H1 histone family in mammals includes eleven members. In higher eukaryotes, all H1 variants have the same general structure, consisting of a central conserved globular domain and less conserved N-terminal and C-terminal tails. These tails are moderately conserved among species, but differ among variants, suggesting a specific function for each H1 variant.
