Cell Fate Acquisition in Maize

PI：Virginia Walbot（斯坦福大学）CoPI：W. Zacheus Cande（加州大学伯克利分校; subawardee）高级人员：丽莎哈珀（加州大学伯克利分校/USDA-ARS）随着复杂生物体的发展，首先建立身体计划，其次是器官的规格，然后是其组成组织，最后是功能细胞类型。 细胞命运获得的调节发生在许多水平上，并反映在细胞内的基因表达和蛋白质含量中，包括对外部信息如周围组织提供的激素的反应。 尽管细胞命运对最终功能的重要性，但这一过程在具有许多细胞类型的复杂组织中很难研究，因为该过程在许多组织中异步发生。 本计画将利用玉米花药内五种主要细胞类型及其同步发育来剖析细胞命运。 基因表达和蛋白质的变化，区分细胞从他们的邻居与不同的命运将被定义。 在花药发育的特定阶段细胞命运获取缺陷的突变体将通过筛选由先前工作建立的玉米雄性不育突变体的大集合来恢复。 通过比较正常花药与突变花药的细胞表达模式，阐明细胞命运获取的正常进展。 所选择的突变体将被描述细胞学和基因表达的模式。 最后，将克隆定义关键突变阶段的基因，以确定正常细胞命运获取所必需的基因产物的性质。 在该项目过程中产生的数据，包括微阵列数据和突变体的细胞学描述，将通过GEO（基因表达综合系统（GEO）（http：//www.ncbi.nlm.nih.gov/geo/）和MaizeGDB（http：//www.example.com）提供。www.maizegdb.org生物资源将通过该项目和玉米遗传合作-库存中心（http：//www.example.com）提供。maizecoop.cropsci.uiuc.edu 在大多数植物和动物中，减数分裂前细胞缺乏同步性，这使得无法深入分析这一特定命运决定所需的步骤。 因此，来自该项目的新知识和见解将阐明减数分裂细胞和周围体细胞的细胞命运规范步骤，这将对理解复杂的植物和动物发育具有普遍意义。 为了使农业专业的本科生熟悉植物遗传学的现代方法，该项目的基因标记部分将在加州理工大学圣路易斯奥比斯波分校进行。项目高级人员将使学生熟悉植物转座子标记的理论，然后培训学生在田间筛选雄性不育突变体，进行遗传杂交以繁殖突变体，与先前鉴定的具有相似表型的突变体进行等位性测试，解剖花药以分析基因表达，并制备DNA样品以克隆新标记的突变等位基因。

PI: Virginia Walbot (Stanford University)CoPI: W. Zacheus Cande (University of California, Berkeley; subawardee)Senior Personnel: Lisa Harper (University of California, Berkeley/USDA-ARS)As complex organisms develop, the body plan is established first, followed by the specification of organs, then their constituent tissues, and finally the functional cell types are designated. The regulation of cell fate acquisition occurs at many levels and is reflected in the gene expression and protein content within the cells and includes responses to external information such as hormones provided by surrounding tissues. Despite the importance of cell fate to final function, this process is difficult to study in complex tissues with many cell types and because the process is occurring asynchronously in many tissues. This project will exploit the five major cell types and their synchronous development within anthers to dissect cell fate in maize. Gene expression and protein changes that distinguish cells from their neighbors with a different fate will be defined. Mutants defective in cell fate acquisition at specific stages of anther development will be recovered by screening large collections of male-sterile mutants of maize established by prior work. The normal progression of cell fate acquisition will be elucidated by comparing cell expression patterns of normal to mutant anthers. Selected mutants will be described cytologically and by their pattern of gene expression. Finally, genes defining key mutant stages will be cloned to determine the nature of the gene product essential for normal cell fate acquisition. Data generated in the course of this project including microarray data and cytological descriptions of mutants will be made available through GEO (Gene Expression Omnibus (GEO) (http://www.ncbi.nlm.nih.gov/geo/) and through MaizeGDB (http://www.maizegdb.org). Biological resources will be available through the project and through the Maize Genetics Cooperation - Stock Center (http://maizecoop.cropsci.uiuc.edu). The lack of synchrony in pre-meiotic cells in most plants and animals has precluded deep analysis of the steps required for this particular fate decision. Consequently, new knowledge and insights from this project will illuminate steps in cell fate specification for the meiotic cells and surrounding somatic cells that will be of general significance in understanding both complex plant and animal development. To acquaint undergraduate students of agriculture focus with modern methods in plant genetics, the gene-tagging component of the project will be conducted at CalPoly-San Luis Obispo. Project senior personnel will acquaint students with the theory of transposon tagging in plants, and then train students to screen for male-sterile mutants in the field, to conduct genetic crosses for propagating mutants, to conduct allelism tests with previously identified mutants conferring similar phenotypes, to dissect anthers for analysis of gene expression, and to prepare DNA samples for the cloning of newly tagged mutant alleles.