Cell differentiation and the Cell Cycle in Arabidopsis

摘要PI：LarkinIOB-0444560在多细胞生物体的发育过程中，细胞分化必须与细胞分裂紧密协调。在动物中，失去对细胞分裂的控制会导致癌症。在某些类型的细胞中，在分化过程中细胞周期发生改变，DNA在没有伴随细胞分裂的情况下复制，导致核DNA含量增加。这个过程的作用被称为内复制，人们对此知之甚少。在以前使用拟南芥叶毛(毛状体)作为细胞分化模型的工作中，暹罗(Siamese，SIM)基因被证明是抑制有丝分裂和建立内复制所必需的。SIM基因现在已经被PI的团队分离出来，预测的基因产物是一个很好的候选基因，可以直接调节细胞周期中起关键调节作用的细胞周期蛋白依赖性激酶的活性。拟南芥有一个大约由四个SIM相关蛋白组成的小基因家族，在其他植物中也存在同源蛋白。该方案的总体目标是确定SIM在毛状体发育过程中调节内周期的功能，并检验SIM基因家族成员可能在植物生长的其他方面，如花、根和维管发育中发挥作用，整合细胞周期和发育信号的假设。预计这项工作将有助于更好地理解协调细胞周期与植物发育的机制。此外，拟议的工作将在研究生、本科生和高中生的教育中发挥作用，这些学生来自不同的背景。

AbstractPI: LarkinIOB-0444560 During the development of multicellular organisms, cell differentiation must be tightly coordinated with cell division. In animals, loss of control of cell division leads to cancer. In some cell types, a modified cell cycle occurs during differentiation in which the DNA is replicated without concomitant cell division, resulting in an increase in nuclear DNA content. The role of this process, termed endoreplication, is poorly understood. In previous work using Arabidopsis leaf hairs (trichomes) as a model for cell differentiation, the SIAMESE (SIM) gene was shown to be required to repress mitosis and establish endoreplication. The SIM gene has now been isolated by the PI's group, and the predicted gene product is a good candidate for a direct regulator of cyclin-dependant kinase activity, which plays a key regulatory role in the cell cycle. Arabidopsis has a small gene family of about four SIM-related proteins, and homologs exist in other plant species. The overall goals of this proposal are to determine the function of SIM in the regulation of endocycling during trichome development, and to test the hypothesis that members of the SIM gene family may play a role in integrating the cell cycle with developmental signals in other aspects of plant growth, such as flower, root, and vascular development. It is expected that this work will lead to a better understanding of the mechanisms coordinating the cell cycle with plant development. Additionally, the proposed work will play a role in the education of graduate students, undergraduates, and high school students from a wide diversity of backgrounds.