BEHAVIOR OF P FACTORS MOVABLE ELEMENTS IN DROSOPHILA

转座子现在被认为在高等生物体中很常见，而且 可能对突变率有很大影响。相似之处在于 逆转录病毒和一些 转座因子。了解这些要素在 高等生物生物学是这项研究的长期目标。 目前的焦点是D。 黑素胃病患者被称为P因子。在一定条件下，P因素导致 一种高度突变的综合征和其他已知的生殖系胡言乱语 统称为杂交不育。 拟议的实验旨在确定P的行为 元素的(A)转位、(B)切除和(C) 监管。我们将特别关注这些组织的作用 P因子入侵种群能力的过程。数据将 也有在其他研究中使用P元素作为工具的应用 果蝇的分子遗传学。我们用一种 分子技术和经典基因技术的平衡结合。 (A)转座：使用原位杂交和其他标准 重组DNA技术，我们将跟随事件的进程当P 因子被引入到基因组中。换位现象 “爆炸”和跨物种入侵的P元素也将 在本实验中进行了研究。P基因插入位点的特异性 将通过放置一个短的(1000个碱基对)插入片段来分析分子 从烧焦的基因到酒精脱氢酶的偏好区 以其他方式不插入P元素的基因。 (B)切除：我们将收集大量P元素切除和 确定事件的范围(部分、完整、侧翼等)那 发生。通过寻找从小到大的变化，我们将测试 假设P元素经历频繁的基因转换，而不是 到简单的切除。一项持续的长期实验将确定 切除是否会导致实验室中P元素的损失 菌株。 (C)调节：P元素的活动受到组织的密切调节 特异性和细胞型。我们将使用一个超可变的双P元素 插入烧焦刚毛基因和体外修饰的集合 P元素来分析这些监管系统中的组成部分。角色 在限制人口中P元素扩散方面的监管将 也可以通过使用原位杂交来跟踪入侵来确定 在监测转位活动抑制的过程中。

Transposable elements are now thought to be common in higher organisms, and might contribute substantially to the mutation rate. Similarities in structure and behavior have been established between retroviruses and some transposable elements. Understanding the role of these elements in the biology of higher organisms is the long term objective of this research. The present focus is on a family of transposable elements in D. melanogaster known as P factors. Under certain conditions, P factors cause a syndrome of high mutability and other germline abberations known collectively as hybrid dysgenesis. The proposed experiments are aimed at determining the behavior of P elements in terms of their (a) transposition, (b) excision, and (c) regulation. Special attention will be given to the roles of these processes in the ability of P factors to invade populations. The data will also have applications for using P elements as tools in other studies of the molecular genetics of Drosophila. We approach these problems with a balanced combination of molecular and classical genetic techniques. (a) Transposition: Using in situ hybridization and other standard recombinant DNA techniques, we will follow the course of events when P factors are introduced into a genome. The phenomena of transpositional "explosions" and inter-specific invasion of P elements will also be investigated in this experiment. The insertional site specificity of P elements will be analyzed by placing a short (1000 base pairs) insertional preference region from the singed gene into a the alcohol dehydrogenase gene where P elements do not otherwise insert. (b) Excision: We will collect a large number of P element excisions and determine the spectrum of events (partial, complete, flanking, etc.) that occur. By looking for changes from small to large elements we will test the hypothesis that P elements undergo frequent gene conversion as opposed to simple excision. A continuing long term experiment will determine whether excision can result in the loss of P elements from laboratory strains. (c) Regulation: P element activity is closely regulated by tissue specificity and cytotype. We will use a hypermutable double P element insertion in the singed bristle gene and a collection of in vitro modified P elements to analyze the components in these regulation systems. The role of regulation in limiting the spread of P elements in a population will also be determined by using in situ hybridization to follow the invasion process while monitoring for suppression of transpositional activity.