Mutations in the essential Drosophila melanogaster gene zw10 disrupt c
hromosome segregation, producing chromosomes that lag at the metaphase
plate during anaphase of mitosis and both meiotic divisions. Recent e
vidence suggests that the product of this gene, DmZW10, acts at the ki
netochore as part of a tension-sensing checkpoint at anaphase onset. D
mZW10 displays an intriguing cell cycle-dependent intracellular distri
bution, apparently moving from the centromere/kinetochore at prometaph
ase to kinetochore microtubules at metaphase, and back to the centrome
re/kinetochore at anaphase (Williams, B.C., M. Gatti, and M.L. Goldber
g. 1996. J. Cell Biol. 134:1127-1140). We have identified ZW10-related
proteins from widely diverse species with divergent centromere struct
ures, including several Drosophilids, Caenorhabditis elegans, Arabidop
sis thaliana, Mus musculus, and humans. Antibodies against the human Z
W10 protein display a cell cycle-dependent staining pattern in HeLa ce
lls strikingly similar to that, previously observed for DmZW10 in divi
ding Drosophila cells. Injections of C. elegans ZW10 antisense RNA phe
nocopies important aspects of the mutant phenotype in Drosophila: thes
e include a strong decrease in brood size, suggesting defects in meios
is or germline mitosis, a high percentage of lethality among the embry
os that are produced, and the appearance of chromatin bridges at anaph
ase. These results indicate that at least some aspects of the function
al role of the ZW10 protein in ensuring proper chromosome segregation
are conserved across large evolutionary distances.