The Role of Prenylation in Meristem Function

茎部分生组织的活动是确定植物整体空中结构的主要决定因素：它的高度，枝、叶和花的数量和位置，成熟的时间，以及花和果实的发育过程。分生组织通过整合外部环境信号和遗传线索来决定原基起始事件的数量和位置。这些活动与调节分生组织内细胞分裂的信号事件同时协调，这确保了分生组织细胞群体的持续维持，同时分生组织将细胞分配给原基和干细胞生产。Running博士设计了一种增敏的拟南芥筛选方法，可以快速识别影响分生组织功能的突变体。在他分离的突变体中，有一种是多瓣的，它表现出对茎部分生组织细胞增殖的逐渐丧失控制，以及更短的身材和更多的花器官。他克隆了PLURIPETALA，发现它编码法尼基转移酶和香叶基转移酶- i之间共享的α亚基。前酰化是一种脂质翻译后修饰，有助于靶蛋白的膜定位和结合，特别是参与信号转导的蛋白质。与动物和酵母系统中的等效戊酰化突变体不同，多瓣植物是有活力和可育的。因此，多瓣茎突变体植物提供了一个独特的机会来测试蛋白质的烯酰化在体内的功能作用，包括对蛋白质亚细胞定位和细胞-细胞运输的影响。此外，利用生物信息学和实验分析鉴定戊烯酰化靶点将有助于深入了解分生组织功能和花发育中涉及的信号通路的组成部分。他的具体目标是：(1)研究戊烯酰化在植物生长发育中的作用；(2)研究戊烯酰化复合物各组分的具体作用及其相互之间的关系；(3)确定戊烯酰化对植物中两种潜在靶蛋白的功能作用。提出的活性将提高对植物中戊烯酰化作用的理解，它涉及许多过程，包括分生组织功能，花发育和激素反应。这些过程引起了许多植物科学家的兴趣，并在农业上有潜在的应用。他对植物发育的多学科研究方法结合了遗传学、分子生物学和细胞生物学技术，将为博士后和学生提供良好的培训机会。此外，他还在为当地高中教师举办一个继续科学教育的暑期讲习班。该计划将包括指导、演示和实验室研究的实践经验，其中一部分将在跑步实验室进行。课堂教学的教育资源也将得到开发。最后，他正在开发一个基于网络的资源，用于传播植物中脂质翻译后修饰的信息，包括戊烯酰化。该数据库包括使用生物信息学工具识别假定靶标的信息，以及那些已被实验证实的信息。本提案中的实验将允许对该数据库进行更新和改进，我们预计这将对植物科学界的成员非常有用，因为脂质翻译后修饰在大量过程中起作用。

The activities of shoot meristems are the primary determinants for establishing the overall aerial architecture of the plant: its stature, the numbers and positions of branches, leaves, and flowers, the time to maturation, and the course of flower and fruit development. Meristems act by integrating external environmental signals with genetic cues to determine numbers and positions of primordia initiation events. These activities are simultaneously coordinated with signaling events that regulate cell divisions within the meristem, which assures continued maintenance of meristem cell populations while the meristem allocates cells to primordia and stem production. Dr. Running designed a sensitized Arabidopsis screen that allows for rapid identification of mutants that affect meristem function. Among the mutants he isolated was pluripetala, which shows a progressive loss of control of shoot meristem cell proliferation, along with shorter stature and extra floral organs. He cloned PLURIPETALA and found that it encodes the alpha subunit shared between the prenylation enzymes farnesyltransferase and geranylgeranyltransferase-I. Prenylation is a lipid posttranslational modification that facilitates membrane localization and association of target proteins, particularly proteins involved in signal transduction. Unlike equivalent prenylation mutants in animal and yeast systems, pluripetala plants are viable and fertile. Therefore, pluripetala mutant plants provide a unique opportunity for testing the functional role of prenylation of proteins in vivo, including the effects of prenylation on protein subcellular localization and cell-cell trafficking. In addition, identification of prenylation targets using bioinformatics and experimental assays will provide insight into components of signaling pathways involved in meristem function and flower development. His specific aims are to: (1) examine the role of prenylation in plant growth and development; (2) examine the specific roles of each component of the prenylation complex and their relation to each other; and (3) determine the functional role of prenylation on two potential target proteins in plants. The proposed activity will improve understanding of the role of prenylation in plants, which is involved in a number of processes, including meristem function, flower development, and hormone responses. These processes are of interest to a wide variety of plant scientists and have potential applications for agriculture. His multidisciplinary approach to the study of plant development combines genetics, molecular biology, and cellular biology techniques and will provide excellent training opportunities for postdoctoral fellows and students. In addition, he is developing a summer workshop for local high school teachers for continuing science education. This program will involve instruction, demonstration, and hands-on experience in laboratory research, which will be carried out in part in the Running lab. Educational resources will also be developed for classroom instruction. Lastly, he is developing a web-based resource for disseminating information on lipid posttranslational modifications, including prenylation, in plants. This database includes information on the identification of putative targets using bioinformatics tools along with those that have been experimentally confirmed. Experiments in this proposal will allow for updates and refinement to this database, which we expect will be very useful to members of the plant scientific community because of the vast number of processes in which lipid post translational modification plays a role.