PLANT GENE REGULATION DURING N-ASSIMILATION/FIXATION

N同化/固定过程中的植物基因调控

• 批准号: 3282080
• 负责人: Gloria CORUZZI
• 金额: $ 20.03万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-12-01 至 1992-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3282080
• 关键词: Leguminoseae; autoradiography; chloroplasts; developmental genetics; gene expression; genetic library; genetic manipulation; genetic mapping; genetic regulation; genetic transcription; glutamate ammonia ligase; messenger RNA; molecular cloning; mutant; nitrogen fixation; nonvisual photosensitivity; nucleic acid probes; nucleic acid sequence; plant genetics; plant growth /development; plant proteins; proteins; radiation genetics; radiotracer; root; transcription factor

The genes encoding the distinct polypeptides of glutamine synthetase (GS) in higher plants present an attractive system to study the molecular mechanisms which regulate nuclear genes involved in two functional processes unique to plants, namely chloroplast development and nitrogen fixation. We propose to examine the genes encoding the distinct forms of GS (chloroplastic and cytosolic), to explore the molecular basis for their differential expression in leaves, roots, and in nitrogen- fixing root nodules of legumes. The specific aims of this study will address the following questions: 1) Are the mRNAs encoding chloroplast or cytosolic GS polypeptides the products of distinct, uniquely regulated GS genes, or alternatively are they the products of differential transcript initiation or RNA processing? 2) What are the factors which contribute to the specific expression of chloroplast GS mRNA in leaves (i.e. light, tissue- type)? 3) What are the molecular mechanisms involved in the induction of GS mRNA in legume roots infected with nitrogen- fixing Rhizobia? cDNA clones encoding the distinct GS polypeptides will be characterized and oligonucleotide probes specific for each GS mRNA species will be used to examine its expression in vivo in leaves (i.e. light/dark), roots, and during nodule development in legumes. The cognate nuclear GS genes will be isolated, characterized, and used as molecular probes, to determine the molecular events which surround their regulated expression in vivo. In particular, we will examine transcriptional regulation by: light, tissue-type, or Rhizobial infection, in isolated nuclei in vitro. Putative trans-acting transcription initiation factors specific for GS gene transcription will be examined in vitro. Wild type and promoter deletion mutants of GS will be introduced into foreign plants (via Ti vectors) and their expression in the transgenic plants monitored in response to light, tissue-type, or Rhizobial infection to define cis-acting DNA elements required for regulated gene expression. In addition to defining the molecular mechanisms which effect a differential regulation of a family of related genes, in the long term, this information may b applied to the modification of existing genes (i.e. in non-legumes) to effect a successful association with Rhizobium.

编码谷氨酰胺不同多肽的基因 高等植物中的合成酶（GS）提出了一个有吸引力的系统 研究调节核基因的分子机制 参与植物独有的两个功能过程，即 叶绿体发育和氮固定。 我们建议 检查编码GS不同形式的基因 （叶绿素和胞质），探索分子基础 它们在叶子，根和氮中的差异表达 固定豆类的根结节。 这项研究的具体目的 将解决以下问题：1）是mRNA编码 叶绿体或胞质GS多肽不同，不同的产物 独特调节的GS基因，或者它们是 差分记录启动或RNA处理的产品？ 2）有助于特定的因素 叶绿体GS mRNA在叶片中的表达（即光，组织 - 类型）？ 3）参与哪些分子机制 在感染了氮气中的豆类根中GS mRNA的诱导 修复根瘤菌？ 编码不同GS多肽的cDNA克隆将是 特征和寡核苷酸探针特有的每个GS mRNA物种将用于检查其在体内的表达 叶（即光/黑暗），根和结节发育期间 豆类。 认知核GS基因将被分离出来， 表征并用作分子探针，以确定 分子事件围绕其受调节的表达 体内。 特别是，我们将通过： 在分离的核中的光，组织类型或根瘤菌感染中 体外。 推定的反式转录引发因子 特定于GS基因转录将在体外检查。 荒野 GS的类型和启动子删除突变体将被引入 外国植物（通过TI载体）及其在 响应光，组织类型或 根瘤菌感染以定义顺式作用DNA元素 用于调节的基因表达。 除了定义 影响A的分子机制 从长远来看，相关基因家族可能会b 应用于现有基因的修改（即在非葡萄糖中） 与根瘤菌成功建立联系。