Histone H2B is one of the 5 main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and long N-terminal and C-terminal tails, H2B is involved with the structure of the nucleosomes. Histone H2B is a structural protein that helps organize eukaryotic DNA. It plays an important role in the biology of the nucleus where it is involved in the packaging and maintaining of chromosomes, regulation of transcription, and replication and repair of DNA. Histone H2B helps regulate chromatin structure and function through post-translational modifications and specialized histone variants. Acetylation and ubiquitination are examples of two post-translational modifications that affect the function of histone H2B in particular ways. Hyperacetylation of histone tails helps DNA-binding proteins access chromatin by weakening histone-DNA and nucleosome-nucleosome interactions. Furthermore, acetylation of a specific lysine residue binds to bromine-containing domains of certain transcription and chromatin regulatory proteins. This docking facilitates the recruitment of these proteins to the correct region of the chromosome. Ubiquitinated histone H2B is often found in regions of active transcription. Through the facilitation of chromatin remodeling, it stimulates transcriptional elongation and sets the stage for further modifications that regulate multiple elements of transcription.