H2BFWT (H2B histone family member W testis-specific) is a 175 amino acid nuclear membrane histone that belongs to the histone H2B family. In contrast to most H2B histones, H2BFWT does not contain the conserved C-terminal residue involved in monoubiquitination, but is structurally indistinguishable from conventional H2B histones. Also varying from other H2B histones, H2BFWT does not participate in the recruitment of chromosome condensation factors or in the assembly of mitotic chromsomes. Expressed in testis, H2BFWT is present in sperm cells and may be essential to telomere function.