Gonzalez Nathalie, Hernould Michel, Delmas Frédéric, Gévaudant Frédéric, Duffe Philippe, Causse Mathilde, Mouras Armand, Chevalier Christian
Unité Mixte de Recherche en Physiologie et Biotechnologie Végétales (Institut de Biologie Végétale Intégrative, Universités de Bordeaux 1), BP 81, 33883 Villenave d'Ornon, Cedex, France.
Plant Mol Biol. 2004 Dec;56(6):849-61. doi: 10.1007/s11103-004-5110-2. Epub 2005 Apr 7.
Early fruit development in tomato (Lycopersicon esculentum Mill.) proceeds in two distinct phases of growth that comprise cell division and cell expansion, respectively. In pericarp and the jelly like locular tissue of tomato fruit, the transition between cell division to cell expansion is characterized by the arrest of mitotic activity, numerous rounds of nuclear DNA endoreduplication and the inhibition of Cyclin-Dependent Kinase A (CDKA) activity. To investigate whether the WEE1 kinase may play a role during the endoreduplication process, we isolated and characterized the tomato homologue for WEE1. The LeWEE1 gene consisted of 10 exons with a predicted 510 amino acid-long protein. The accumulation of the corresponding transcripts was associated with mitotically active organs: developing fruits, seeds and roots. Interestingly, LeWEE1was expressed in the jelly like locular tissue concomitant with endoreduplication during fruit development. Using tobacco BY-2 synchronized cells, we showed that the WEE1 gene expression is cell-cycle regulated with a maximum transcript accumulation at S phase. Our data indicate the putative dual contribution of LeWEE1 in the classical cell cycle and the endocycle.
番茄（Lycopersicon esculentum Mill.）果实的早期发育经历两个不同的生长阶段，分别包括细胞分裂和细胞扩张。在番茄果实的果皮和果冻状的胎座组织中，从细胞分裂到细胞扩张的转变以有丝分裂活动的停止、多轮核DNA内复制以及细胞周期蛋白依赖性激酶A（CDKA）活性的抑制为特征。为了研究WEE1激酶是否可能在内复制过程中发挥作用，我们分离并鉴定了番茄中WEE1的同源物。LeWEE1基因由10个外显子组成，预测编码一个长度为510个氨基酸的蛋白质。相应转录本的积累与有丝分裂活跃的器官相关：发育中的果实、种子和根。有趣的是，在果实发育过程中，LeWEE1在果冻状的胎座组织中表达，同时伴有内复制。利用烟草BY - 2同步化细胞，我们发现WEE1基因的表达受细胞周期调控，在S期转录本积累达到最大值。我们的数据表明LeWEE1在经典细胞周期和内循环中可能具有双重作用。
