We report the characterization of a maize Wee1 homologue and its expression
in developing endosperm, Using a 0.8-kb cDNA from an expressed sequence ta
g project, me isolated a 1.6-kb cDNA (ZmWee1), which encodes a protein of 4
03 aa with a calculated molecular size of 45.6 kDa, The deduced amino acid
sequence shows 50% identity to the protein kinase domain of human Wee1. Ove
rexpression of ZmWee1 in Schizosaccharomyces pombe inhibited cell division
and caused the cells to enlarge significantly. Recombinant ZmWee1 obtained
from Escherichia coli is able to inhibit the activity of p13(suc1)-adsorbed
cyclin-dependent kinase from maize. ZmWee1 is encoded by a single gene at
a locus on the long arm of chromosome 4. RNA gel blots showed the ZmWee1 tr
anscript is about 2.4 kb in length and that its abundance reaches a maximum
15 days after pollination in endosperm tissue. High levels of expression o
f ZmWee1 at this stage of endosperm development imply that ZmWee1 plays a r
ole in endoreduplication. Our results show that control of cyclin-dependent
kinase activity by Wee1 is conserved among eukaryotes, from fungi to anima
ls and plants.