BEHAVIOR OF P FACTORS MOVABLE ELEMENTS IN DROSOPHILA

转座因子现在被认为在高等生物中很常见， 可能对突变率有很大的影响 相似之处 逆转录病毒和一些病毒之间的结构和行为已经确定， 转座因子 了解这些要素在 高等生物学是这项研究的长期目标。 本研究的重点是D. 称为P因子。 在一定条件下，P因子引起 一种高突变性综合征和其他已知的生殖系畸变 统称为杂种发育不全。 所提出的实验旨在确定P （a）换位，（B）切除，和（c） 调控 将特别注意以下方面的作用： P因子入侵种群的能力。 数据将 也有应用程序使用P元素作为工具，在其他研究 果蝇的分子遗传学 我们以一种 分子和经典遗传技术的平衡组合。 (a)转座：使用原位杂交和其他标准 重组DNA技术，我们将遵循事件的过程时，P 因子被引入基因组。 换位现象 “爆炸”和P元素的种间入侵也将是 在这个实验中研究。 P插入位点的特异性 元件将通过放置短的（1000个碱基对）插入序列来分析。 从烧焦的基因的偏好区域转化为乙醇脱氢酶 P元件不插入的基因。 (b)切除：我们将收集大量的P元素切除， 确定事件谱（部分、完全、侧翼等）的 发生. 通过寻找从小元素到大元素的变化， 假设P元件经历频繁的基因转换， 简单的切除 一个持续的长期实验将决定 切除是否会导致实验室P元素丢失 菌株 (c)调节：P元素活性受组织密切调节 特异性和细胞型。 我们将使用一个超可变的双P元素 插入烧焦的刚毛基因，并收集体外修饰的 P元素来分析这些调节系统的组成部分。 的作用 限制P元素在种群中传播的调节作用将 也可以通过原位杂交来确定， 过程，同时监测易位活性的抑制。

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.