MUTATOR TRANSPORTABLE ELEMENTS OF MAIZE

转座因子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 原核生物，包括引起人类疾病的生物，转座子 抗生素耐药基因之间的物种。在真核生物中，转座子 在进化时间尺度上或在一个特定的时间尺度内产生等位基因多样性。 单一有机体。这项工作的目标是了解如何 Mutator转座因子的活性受生命周期的调控 它的自然宿主玉米突变子（Mu）元件转座子由 MuDR产生任何真核生物中最高的正向突变频率 转座子Mutator表现出两种形式的发育调控：[1] 由于元件主要在细胞命运之后是移动的，因此定时较晚 [2]两种转座机制， 生殖细胞和配子中的索马和复制插入。怎么 由MuDR介导的多种转录本和潜在蛋白质 发育时间和两种转座机制？仔细 将分析分期组织中的产物外观和丰度， 几种具有不同调控行为的突变体系， 表达myc标记的MUR蛋白的转基因玉米。可能的 反义转录物对发育调控的贡献将是 通过表达发育的正义和反义转录物来分析 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启动子。突变体活动将是 在表达单个MuDR编码的 产品;标记的Mu元件（含有pBluescript质粒）将允许 恢复新的插入，以区分“仅切割”“切割”和 “粘贴”和“缺口修复剪切粘贴”模型; 标记的元素将用于定义Mu的时间和频率 在胚芽中复制转座过程中的元件扩增 细胞和配子。体外生物化学研究将检查DNA 编码的转座的结合特性和酶活性 MuDR以确定“切割和转移”是否需要不同的转座酶。 粘贴”和复制转座。

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.