The prime candidate for specifying centromere identity is the array of nucleosomes assembles with CENP-A [1]. CENP-A recruits a nucleosome associated complex (NAC) comprised of CENP-M along with two other proteins [1]. Assembly of the CENP-A NAC at centromeres is partly dependant on CENP-M. The CENP-A NAC is essential, as disruption of the complex causes errors of chromosome alignment and segregation that preclude cell survival [1].

1: The human CENP-A centromeric nucleosome-associated complex. Foltz DR, Jansen LE, Black BE, Bailey AO, Yates JR 3rd, Cleveland DW; Nat Cell Biol. 2006;8:458-469. PMID:16622419