Molecular genetics of the Mu transposons of maize

罗伯逊突变体（Mu）转座因子系统是一种 玉米中的高活性转座子系统， 突变频率是背景的50倍 Mu系统 有几个不寻常的属性，使其区别于其他 真核生物转座因子系统，并且很少有人知道 关于Mu元素转位的机制。 的 拟议的研究旨在更好地了解这一点 转座子系统在分子水平上。 我们将描述 先前产生的遗传物质， 转座特性如下。 我们计划克隆， 描述一个衍生的Mu元素，可遗传的表现出10 切除频率增加100倍 祖先Mu1元件。 这个元素可以用来回答 关于Mu换位的具体问题，以及提供一个 切除活性的敏感标记。 我们还将分析一个穆 其中转座子系统被持续的 自交，以了解剂量依赖性的基础 Mu转座子活性的调节。 除了上述 研究，我们将开发Mu转基因中的转座检测方法， 双子叶植物 这些试验将用于确定 转座的序列要求，以及 我们之前发现的Mu末端的特定序列 被认为可能在转座中发挥重要作用。 %%% 由于Mu转座子的不寻常特性，这些研究 应该会增加我们对转座机制和DNA 重新安排。

The Robertson's Mutator (Mu) transposable element system is a highly active transposon system in maize that generates new mutations at frequencies of 50-fold over background. The Mu system has several unusual properties that distinguish it from other eukaryotic transposable element systems, and there is little known regarding the mechanism of transposition of the Mu elements. The proposed studies are aimed towards a better understanding of this transposon system at the molecular level. We will characterize previously generated genetic material which show altered transposition properties as follows. We plan to clone and characterize a derivative Mu element that heritable exhibits a 10 to 100 fold increase in excision frequency relative to the progenitor Mu1 element. This element can be used to answer specific questions about Mu transposition, as well as providing a sensitive marker for excision activity. We will also analyze a Mu lineage in which the transposon system was inactivated by continued selfing, in order to understand the basis of dose-dependent regulation of Mu transposon activity. In addition to the above studies, we will develop assays for Mu transposition in transgenic dicotyledenous plants. The assays will be used to determine the sequence requirements for transposition, and the function of specific sequences within the Mu termini that we have previously identified as likely to play an important role in transposition. %%% Due to the unusual properties of Mu transposons, these studies should add to our knowledge of mechanisms of transposition and DNA re-arrangements.