CENP-C is necessary but not sufficient to induce formation of a functional centromere.
CENP-C is an evolutionarily conserved centromeric protein. We have used the chicken DT40 cell line to test the idea that CENP-C is sufficient as well as necessary for the formation of a functional centromere. We have compared the effects of disrupting the localization of CENP-C with those of inducibly overexpressing the protein. Removing CENP-C from the centromere causes disassembly of the centromere protein complex and blocks cells at the metaphase-anaphase junction. Overexpressed CENP-C is associated with an increase in errors of chromosome segregation and inhibits the completion of mitosis. However, the excess CENP-C does not disrupt the native centromeres detectably and does not associate with another conserved centromere protein, ZW10. The distribution of the excess CENP-C changes during the cell cycle. In metaphase, the excess CENP-C coats the chromosome arms. At the metaphase-anaphase transition, the excess CENP-C clusters, and during interphase it is present in large bodies which form around pre-existing centromeres which are also clustered. These results indicate that CENP-C is necessary but not sufficient for the formation of a functional centromere and suggest that the structure of CENP-C may be regulated during the cell cycle.
Fukagawa
T
T
Biochemistry Department, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
Pendon
C
C
Morris
J
J
Brown
W
W
D001483:Base Sequence; D002453:Cell Cycle; D002460:Cell Line; D002503:Centromere; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D002875:Chromosomes; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008938:Mitosis
D002868:Chromosomal Proteins, Non-Histone; D017931:DNA Primers; D004268:DNA-Binding Proteins; C060905:centromere protein C