The domain structure of centromeres is conserved from fission yeast to humans

The centromeric DNA of fission yeast is arranged with a central core flanke d by repeated sequences. The centromere-associated proteins, Mis6p and Cnp1 p (SpCENP-A), associate exclusively with central core DNA, whereas the Swi6 protein binds the surrounding repeats. Here, electron microscopy and immun ofluorescence light microscopy reveal that the central core and flanking re gions occupy distinct positions within a heterochromatic domain. An "anchor " structure containing the Ndc80 protein resides between this heterochromat ic domain and the spindle pole body. The organization of centromere-associa ted proteins in fission yeast is reminiscent of the multilayered structures of human kinetochores, indicating that such domain structure is conserved in eukaryotes.