MUTATOR TRANSPORTABLE ELEMENTS OF MAIZE

转座元件通过产生等位基因介导快速遗传变化 多样性和重组和易位的“热点”。在……里面 原核生物，包括引起人类疾病的有机体，转座子移动 物种间的抗生素耐药基因。在真核生物中，转座子 在进化时间尺度上或在 单一的有机体。拟议工作的目标是了解如何 突变体转座子活性受生命周期调控 它的自然寄主玉米。诱变子(Mu)转座子被动员 MuDR产生的正向突变频率是所有真核生物中最高的 转座子。突变体表现出两种形式的发育调节：[1] 较晚的时间，因为元素主要在细胞命运之后移动 确定，和[2]两种移位机制与切除在 生殖细胞和配子中的胞体和复制插入。做什么 MuDR编码的不同转录本和潜在蛋白参与调节 发育时序和两种转位机制？小心地 将对分期组织进行产品外观和丰度分析 几个具有不同调控行为的突变体系 表达myc标记MUR蛋白的转基因玉米。可能的 反义转录本对发育调控的贡献将是 通过表达正义和反义转录本来分析发育 将通过表达正义和反义RNA来分析调控 转基因玉米中的热激促进剂。诱变者活动将是 在表达单个MuDR编码的转基因植物中的重建 产品；标记的Mu元素(包含pBluescript质粒)将允许 恢复新插入以区分“Cut Only”“Cut”和 “粘贴”和“剪贴缝隙修复”的体细胞切除模型； 标记的元素将用于定义Mu的定时和频率 生殖细胞复制转位过程中的元件扩增 细胞和配子。体外生化研究将检测DNA 编码的转座子的结合特性和酶活性 MUDR以确定是否需要不同的转座酶 粘贴“和复制移位。

Transposable elements mediate rapid genetic change by creating allelic diversity and "hot spots" for recombination and translocations. In prokaryotes, including organisms causing human disease, transposons move antibiotic resistance genes between species. In eukaryotes, transposons generate allelic diversity on an evolutionary time scale or within a single organism. The goal of the proposed work is to understand how Mutator transposable element activities are regulated with the life cycle of its natural host, maize. Mutator (Mu) element transposons mobilized by MuDR produce the highest forward mutation frequency of any eukaryotic transposon. Mutator exhibits two forms of developmental regulation: [1] late timing as elements are mobile primarily after cell fate determination, and [2] two transposition mechanisms with excision in the soma and replicative insertion in the germinal cells and gametes. How do the diverse transcripts and potential proteins encoded by MuDR mediate developmental timing and the two transposition mechanisms? Carefully staged tissues will be analyzed for product appearance and abundance in several Mutator lines with different regulatory behaviors and in transgenic maize expressing myc-tagged MUR proteins. The possible contribution of antisense transcripts to developmental regulation will be analyzed by expressing sense and antisense transcripts to developmental regulation will be analyzed by expressing sense and antisense RNA from heat shock promoters in transgenic maize. Mutator activities will be reconstructed in transgenic plants expressing individual MuDR-encoded products; marked Mu elements (containing a pBluescript plasmid) will allow recovery of new insertions to distinguish between "cut only" "cut and paste" and "cut and paste with gap repair" models of somatic excision; the marked elements will be used to define the timing and frequency of Mu element amplification during replicative transposition in the germinal cells and gametes. In vitro biochemical studies will examine the DNA binding properties and enzymatic activities of the transposes encoded by MuDR to determine if different transposases are required for "cut and paste" and replicative transposition.