Human CENP-A contains a histone H3 related histone fold domain that is required for targeting to the centromere

Centromeres are the differentiated chro- mosomal domains that specify the mitotic behavior of chromosomes. To examine the molecular basis for the specification of eentromeric chromatin, we have cloned a human eDNA that encodes the 17-kD historic-like centromere antigen, CENP-A. Two do- mains are evident in the 140 aa CENP-A polypeptide: a unique NH₂-terminal domain and a 93-amino acid COOH-terminal domain that shares 62% identity with nucleosomal core protein, histone H3. An epitope tagged derivative of CENP-A was faithfully targeted to centromeres when expressed in a variety of animal cells and this targeting activity was shown to reside in the histone-like COOH-terminal domain of CENP-A. These data clearly indicate that the assembly of cen- tromeres is driven, at least in part, by the incor- poration of a novel core histone into centromeric chromatin.