Histone variants are key epigenetic players that regulate transcription, repair, replication, and recombination of genomic DNA. Histone variant incorporation into nucleosomes induces structural diversity of nucleosomes, consequently leading to the structural versatility of chromatin. Such chromatin diversity created by histone variants may play a central role in the epigenetic regulation of genes. Each histone variant possesses specific biochemical and physical characteristics, and thus the preparation methods are complicated. Here, we introduce the methods for the purification of human histone variants as recombinant proteins, and describe the preparation methods for histone complexes and nucleosomes containing various histone variants. We also describe the detailed method for the preparation of heterotypic nucleosomes, which may function in certain biological phenomena. These methods are useful for biochemical, structural, and biophysical studies.
Keywords: Chromatin; Histone; Histone variants; Nucleosome reconstitution; Recombinant histones.