Molecular Biology and Developmental Functions of Wall Extension Proteins (Expansins) in Plant Cell Enlargement

植物细胞增大中细胞壁延伸蛋白（扩张蛋白）的分子生物学和发育功能

• 批准号: 9317864
• 负责人: Daniel Cosgrove
• 金额: $ 63.06万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-03-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9317864&HistoricalAwards=false
• 关键词: Molecular; Biology; Developmental; Functions; Wall

9317864 Cosgrove The PI's laboratory has identified and characterized two proteins ("expansins") from cucumber hypocotyl walls that appear to mediate the acid-extension response of isolated plant cell walls. This proposal outlines a five year plan to investigate the developmental functions of these proteins and to elucidate the mechanism of their action. The proposal has five major objectives. These are: a) to clone and sequence the two expansin genes from cucumbers and one expansin gene from Arabidopsis, and to identify conserved sequences that may code for the active site of the expansins; b) To analyze the spatial and temporal patterns of the expansin gene expression at the mRNA level and to relate these to developmental patterns of growth; c) To construct transgenic plants with reduced or enhanced levels of expansin expression and to analyze the resulting alterations in phenotype; d) To map the Arabidopsis gene and test whether previously identified Arabidopsis growth mutants are deficient in expansin production; e) to express an expansin gene in E. coli as a means of verifying gene identity and as source for protein for studies on isolated cell walls and living cells. %%% This study is important because it will establish the role of this novel class of proteins in plant growth. Expansins are the only wall proteins found to date that have the ability to induce extension in isolated plant cell walls. The growth response these protein mediate seems to be common in cells with cellulosic walls and it may contribute to auxin-stimulated growth. The understanding of the role of expansins and their mech anism of action will most likely lead to important discoveries of the molecular basis of plant cell wall changes during plant growth. *** { 7 u { ! Z ! Z Z ! F { { ( Times New Roman Symbol & Arial ` ` U " h % 5 Dr. Geza Hrazdina Dr. Geza Hrazdina

9317864科斯格罗夫 PI的实验室已经鉴定并表征了来自黄瓜下胚轴壁的两种蛋白质（“扩展蛋白”），它们似乎介导了分离的植物细胞壁的酸延伸反应。 该提案概述了一个五年计划，以研究这些蛋白质的发育功能，并阐明其作用机制。 该提案有五个主要目标。 这些是：a）克隆和测序来自黄瓜的两个扩展蛋白基因和来自拟南芥的一个扩展蛋白基因，并鉴定可能编码扩展蛋白活性位点的保守序列; B）在mRNA水平上分析扩展蛋白基因表达的空间和时间模式，并将这些与生长发育模式相关联; c）构建扩展蛋白表达水平降低或增强的转基因植物，并分析由此产生的表型变化; d）定位拟南芥基因并测试先前鉴定的拟南芥生长突变体是否在扩展蛋白产生方面有缺陷; e）在E.大肠杆菌作为一种手段，验证基因的身份，并作为蛋白质的来源，对分离的细胞壁和活细胞的研究。 这项研究很重要，因为它将确定这类新型蛋白质在植物生长中的作用。 扩展蛋白是迄今为止发现的唯一具有诱导分离的植物细胞壁延伸的能力的壁蛋白。 这些蛋白质介导的生长反应似乎在具有纤维素壁的细胞中是常见的，并且它可能有助于生长素刺激的生长。 对扩展蛋白的作用及其作用机制的了解将很可能导致植物生长过程中细胞壁变化的分子基础的重要发现。 *** { 7 u { ! Z ! Z Z ! F { { ( Times New Roman 符号Arial "“ U " H % 5 Geza Hrazdina博士