A maize homolog of mammalian CENPC is a constitutive component of the inner kinetochore.
Genes for three maize homologs (CenpcA, CenpcB, and CenpcC) of the conserved kinetochore assembly protein known as centromere protein C (CENPC) have been identified. The C-terminal portion of maize CENPC shares similarity with mammalian CENPC and its yeast homolog Mif2p over a 23-amino acid region known as region I. Immunolocalization experiments combined with three-dimensional light microscopy demonstrated that CENPC is a component of the kinetochore throughout interphase, mitosis, and meiosis. It is shown that sister kinetochore separation occurs in two discrete phases during meiosis. A partial separation of sister kinetochores occurs in prometaphase I, and a complete separation occurs in prometaphase II. CENPC is absent on structures known as neocentromeres that, in maize, demonstrate poleward movement but lack other important features of centromeres/kinetochores. CENPC and a previously identified centromeric DNA sequence interact closely but do not strictly colocalize on meiotic chromosomes. These and other data indicate that CENPC occupies an inner domain of the maize kinetochore.
Department of Botany, University of Georgia, Athens, Georgia 30602, USA. kelly@dogwood.botany.uga.edu
R K
RK
Dawe
L M
LM
Reed
H G
HG
Yu
M G
MG
Muszynski
E N
EN
Hiatt
D000595:Amino Acid Sequence; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000235:genetics*; D007399:Interphase; D008938:Mitosis; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000235:genetics*
D002868:Chromosomal Proteins, Non-Histone; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C060905:centromere protein C