A replicated chromosome includes two kinetochores that control chromosome segregation during mitosis. The
Centromere Protein-A, CENP-A, is a Histone H3-like
protein that contains a C-terminal H3-like domain, which
is required for centromere localization of CENP-A, and an
antigenic N-terminal domain.
CENP-A, originally isolated from HeLa cells, is essential
for kinetochore targeting of CENP-C. In the presence of
DNA CENP-A forms an octa-meric complex with histones
H4, H2A, H2B. CENP-A specifically localizes to active
centromeres and is a component of specialized
centromeric nucleosomes, on which kinetochores are
assembled. CENP-A is essential for nucleosomal
packaging of centromeric DNA at interphase and functions as
a centromere formation marker on the chromosome.