MUTATOR TRANSPORTABLE ELEMENTS OF MAIZE

玉米突变可转运元件

• 批准号: 2187209
• 负责人: VIRGINIA E WALBOT
• 金额: $ 23.85万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1997-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2187209
• 关键词: RNA splicing; RNase protection assay; antisense nucleic acid; corn; developmental genetics; electroporation; gene expression; gene mutation; genetic promoter element; genetic regulation; genetic terminator element; genetic transcription; genetically modified plants; molecular cloning; northern blottings; nucleic acid sequence; phenotype; plant genetics; posttranscriptional RNA processing; reporter genes; tobacco; transposon /insertion element

Transposons produce genetic diversity during the life of individuals as well as over evolutionary time; their activities are implicated in many human genetic diseases. Maize is a model higher eukaryote ideally suited for analyzing the developmental regulation of transposons. The Mutator transposable element family is among the most active in higher eukaryotes; Mutator lines contain dozens of mobile Mu elements whose insertion elevates mutation frequency greater than 100-fold. Mutator transposon activities are stringently regulated during host development: Mu element excision, insertion and copy number amplification are all restricted to the terminal mitotic divisions of tissue differentiation. The outcome of Mutator activation depends on the tissue: in the soma, elements excise, but in germ cells elements amplify and insert (without excision, hence a very low germinal reversion frequency). The regulatory Mutator element was recently cloned and sequenced; it encodes two convergently transcribed genes with a shared termination region. With the "master" element in hand, our long-term objectives are to understand the developmental regulation of Mutator activities and how the interplay of host and element-encoded activities determines the differential behavior of Mu elements in somatic and germinal cells. Our current goals include characterizing Mu9, the presumptive "master" Mutator element, pursuing three specific aims: to use transient assays to characterize more completely the promoters, terminators and splicing of the two genes; to provide molecular proof that Mu9 is an "autonomous element" by assaying excision in transient assays and both excision and insertion in transgenic plants; and to determine the functions of the Mu9 gene products in transposition and/or element expression. Using a recently isolated Mutator line with novel phenotypes -- early somatic excision, high germinal reversion frequency, and drastic copy number reduction -- we will use RNase protection analyses to determine how the expression of Mu9 compares in standard and the variant Mutator lines. These data should provide insight into the developmental regulation of Mutator activity. Capitalizing on the drastic copy number reduction of the novel line, we will test a simplified gene tagging and cloning protocol.

转座子在个体的生活中产生遗传多样性 以及进化的时间；他们的活动与许多人有关 人遗传疾病。 玉米是一种理想适合的高级真核生物的模型 用于分析转座子的发育调节。 突变器 转座元素家族是高等真核生物中最活跃的家族之一。 突变器线包含数十个移动MU元素的插入 提升突变频率大于100倍。 突变器转座子 活动在主机开发过程中受到严格调节：MU元素 切除，插入和拷贝数放大都仅限于 组织分化的末端有丝分裂分裂。 结果 突变器的激活取决于组织：在soma中，元素消除， 但是在生殖细胞中，元素会放大和插入（无需切除，因此 非常低的生发逆转频率）。 调节突变器元件 最近被克隆并测序；它编码两个收集转录的 具有共享终止区域的基因。 带有“主”元素 手，我们的长期目标是了解发展 调节突变器活动以及宿主与宿主的相互作用如何 元素编码的活动决定MU的差异行为 体细胞和生发细胞中的元素。 我们目前的目标包括 表征Mu9，推定的“主”突变器元素，追求 三个特定的目的：使用瞬态测定以表征更多 完全是两个基因的启动子，终止和剪接；到 通过分析提供分子证明MU9是“自主元素” 切除瞬态测定以及转基因中的切除和插入 植物;并确定MU9基因产物的功能 换位和/或元素表达式。 使用最近隔离的 具有新表型的突变器线 - 早期切除，高 生发恢复频率和急剧拷贝数减少 - 我们将 使用RNase保护分析来确定MU9的表达方式 在标准和变体突变器线上进行比较。 这些数据应该 提供有关突变活性的发育调控的洞察力。 利用新颖线的急剧拷贝数减少，我们 将测试简化的基因标记和克隆协议。