Contributions of Histone Variants in Nucleosome Structure and Function

[Display omitted] •Histone variants play vital roles in the epigenetic regulation of eukaryotic chromatin.•Histone variants confer structural and physical diversities to the nucleosome core particle.•Up to 50% amino acid sequence differences are found between histone variants and canonical histones. Chromatin compacts genomic DNA in eukaryotes. The primary chromatin unit is the nucleosome core particle, composed of four pairs of the core histones, H2A, H2B, H3, and H4, and 145–147 base pairs of DNA. Since replication, recombination, repair, and transcription take place in chromatin, the structure and dynamics of the nucleosome must be versatile. These nucleosome characteristics underlie the epigenetic regulation of genomic DNA. In higher eukaryotes, many histone variants have been identified as non-allelic isoforms, which confer nucleosome diversity. In this article, we review the manifold types of nucleosomes produced by histone variants, which play important roles in the epigenetic regulation of chromatin.