Sun Y, Dilkes B P, Zhang C, Dante R A, Carneiro N P, Lowe K S, Jung R, Gordon-Kamm W J, Larkins B A
Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA.
Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):4180-5. doi: 10.1073/pnas.96.7.4180.
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 tag project, we isolated a 1.6-kb cDNA (ZmWee1), 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 Wee1. Overexpression 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 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 ZmWee1 at this stage of endosperm development imply that ZmWee1 plays a role in endoreduplication. Our results show that control of cyclin-dependent kinase activity by Wee1 is conserved among eukaryotes, from fungi to animals and plants.
我们报道了玉米Wee1同源物的特性及其在发育中的胚乳中的表达。利用来自一个表达序列标签项目的0.8 kb cDNA，我们分离出了一个1.6 kb的cDNA（ZmWee1），它编码一个403个氨基酸的蛋白质，计算分子量为45.6 kDa。推导的氨基酸序列与人类Wee1的蛋白激酶结构域有50%的同一性。ZmWee1在粟酒裂殖酵母中的过表达抑制了细胞分裂并导致细胞显著增大。从大肠杆菌获得的重组ZmWee1能够抑制来自玉米的p13(suc1)吸附的细胞周期蛋白依赖性激酶的活性。ZmWee1由位于4号染色体长臂上一个位点的单基因编码。RNA凝胶印迹显示ZmWee1转录本长度约为2.4 kb，其丰度在授粉后15天在胚乳组织中达到最大值。在胚乳发育的这个阶段ZmWee1的高水平表达意味着ZmWee1在内复制中起作用。我们的结果表明，从真菌到动物和植物，真核生物中由Wee1对细胞周期蛋白依赖性激酶活性的控制是保守的。
