Functional and Molecular Analysis of Brick Genes in Maize

玉米 Brick 基因的功能和分子分析

• 批准号: 9817084
• 负责人: Laurie Smith
• 金额: $ 30万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9817084&HistoricalAwards=false
• 关键词: Functional; Molecular; Analysis; Brick; Genes

During development, cells acquire a wide variety of shapes that aretailored to their differentiated functions. The shape of a plant cell isdictated by the wall that surrounds it, a complex and highly structuredmatrix of carbohydrates, proteins, phenolic compounds, and lipids. Thepattern in which a wall expands as that cell enlarges depends upon itscomposition and structure, which in turn is controlled by the cell within.The work described in this proposal is aimed at furthering ourunderstanding of mechanisms governing plant cell morphogenesis. Mutations in three maize genes required for leaf epidermal cellmorphogenesis have been isolated. In all of these "brick" mutants,epidermal cells expand to achieve a normal size and overall rectangularshape, but are completely lacking the marginal lobes characteristic of leafblade epidermal cells. Preliminary studies of brk mutant phenotypes haveled to two alternative hypotheses for Brk gene function. The first is thatBrk genes promote intracellular asymmetries, which direct non-uniformpatterns of deposition/secretion of wall components, producing specializedepidermal cell shapes. The second is that Brk genes are required for thesynthesis of particular wall components needed to achieve non-uniformpatterns of cell expansion. In the experiments proposed under Specific Aim1, these hypotheses are explored through further characterization ofintracellular and extracellular events associated with the formation ofepidermal cell lobes, and how these events are altered in each of the 3 brkmutants. Specific Aim 2 is to use genetic mosaic analysis to determinewhether each gene functions cell autonomously or non-autonomously tocontrol cell shape. To pursue an understanding of Brk gene function inmolecular terms, Specific Aim 3 is to clone one of the Brk genes usingtransposon tagging. Subsequent to cloning one of the Brk genes, the aminoacid sequence of its predicted protein product will be determined andanalyzed for homology to other proteins or protein motifs, and theexpression of this gene will be examined to determine how it relates toepidermal cell morphogenesis.

在发育过程中，细胞获得各种各样的形状，以适应其不同的功能。 植物细胞的形状由其周围的细胞壁决定，细胞壁是碳水化合物、蛋白质、酚类化合物和脂质的复杂且高度结构化的基质。 随着细胞增大，壁扩张的模式取决于其组成和结构，而组成和结构又受内部细胞的控制。本提案中描述的工作旨在进一步了解控制植物细胞形态发生的机制。叶表皮细胞形态发生所需的三个玉米基因的突变已被分离出来。 在所有这些“砖”突变体中，表皮细胞扩张以达到正常大小和整体矩形形状，但完全缺乏叶片表皮细胞的边缘叶特征。 对 brk 突变表型的初步研究得出了 Brk 基因功能的两种替代假设。 第一个是 Brk 基因促进细胞内不对称，从而引导壁成分沉积/分泌的不均匀模式，产生特殊的表皮细胞形状。 第二个是 Brk 基因是合成实现非均匀细胞扩张模式所需的特定壁成分所必需的。 在特定目标 1 下提出的实验中，通过进一步表征与表皮细胞叶形成相关的细胞内和细胞外事件以及这些事件如何在 3 个 brk 突变体中发生改变来探索这些假设。 具体目标 2 是利用遗传嵌合分析来确定每个基因是自主地发挥细胞功能还是非自主地控制细胞形状。 为了从分子角度理解 Brk 基因功能，具体目标 3 是使用转座子标签克隆 Brk 基因之一。 克隆 Brk 基因之一后，将确定其预测蛋白质产物的氨基酸序列并分析与其他蛋白质或蛋白质基序的同源性，并检查该基因的表达以确定其与表皮细胞形态发生的关系。