Definition: Specialized chromosome region reacting to the spindle at nuclear division and to which spindle fibers attach during cell division. Appears as a distinct "waist" by microscopy. In a few organisms the centromeric properties are distributed over the entire length of the chromosome (diffuse centromere).
At each mitosis, accurate segregation of every chromosome is ensured by the assembly of a kinetochore at each centromeric locus.
Six foundation kinetochore proteins that assemble hierarchically and co-dependently have been identified in vertebrates. CENP-A, Mis12, CENP-C, CENP-H and CENP-I localize to a core domain of centromeric chromatin. The sixth protein, CENP-B, although not essential in higher eukaryotes, has homologues in fission yeast that bind pericentric DNA and are essential for heterochromatin formation.
Foundation kinetochore proteins have various roles and mutual interactions, and their associations with centromeric DNA and heterochromatin create structural domains that support the different functions of the centromere.
See also
mitosis
kinetochore
CENPs
References
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