Characterization of inaize (Zea mays L.) Weel and its activity in developing endosperm

摘要

We report the charactcrization of a maize Weel homologue and its expression in developing endosperm. Using a 0.8-kb cDNA from an expressed sequence tag project, we isolated a 1.6-kb cDNA (Zm Weel), which encodes a protein of 403 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 Weel. Overexpression of ZmWeel in Schizosaccharomyces pombe inhibited cell division and caused the cells to enlarge signiftcantly. Recombinant ZmWeel obtained from Escherichia coli is able to inhibit the activity of pl3~sucl-adsorbed cyclin-dependent kinase from maize. ZmWeel is encodwed by a single gene at a locus on the long arm of chromosome 4. RNA gel blots showed the ZmWeel transcript 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 of ZmWeel at this stage of endosperm development imply that ZmWeel plays a role in endoreduplication. Our results sbow that control of cyclin- dcpendent kinase activity by Weel is conserved among eu- karyotes, from fungi to antmals and plants.