Histone Cluster 1, H2ba (HIST1H2BA)

By sequencing histones purified from human sperm, followed by database analysis, Zalensky et al. (2002) identified HIST1H2BA, which they called TSH2B. The deduced 127-amino acid protein shares 85% identity with somatic H2B.1, but it has more potential phosphorylation and myristoylation sites.

TSH2B shares 95% and 93% amino acid identity with mouse and rat Tsh2b, respectively. RT-PCR detected TSH2B expression exclusively in testis. Using several extraction procedures, Zalensky et al. (2002) found that TSH2B was relatively tightly bound to sperm chromatin. Immunolocalization detected TSH2B in a punctate localization in mature sperm, but it was not part of the telomere-binding complex.