DEVELOPMENTAL REGULATION IN DROSOPHILA

这项建议的目的是加深我们对 转座元件P元件的生物学及其调控 在黑腹果蝇体内发现。P元素特别是 有趣的是因为他们的换位既是基因上的 调节(P-M杂交性发育不全综合征)和组织特异性 (转座只发生在生殖系中，而不发生在体细胞中 纸巾)。最近，我们已经证明了生殖系的特异性 P元素转位在mRNA水平上的调控 拼接。作为这些研究的继续，我们将：(1) 向核苷酸确定P的哪些顺式作用序列 胚系需要元件前-mRNA转录本 专一性。(二)确定空间格局和发展格局 用β-半乳糖染色检测P元素生殖系特异性剪接 化验。(3)从基因上筛选编码基因的突变 生殖系特异性RNA剪接因子。(4)试图孤立 并保持果蝇生殖系细胞系能够 拼接P元素胚系特异性内含子。(5)企图 建立一种体外剪接系统，使 生殖系的生化鉴定与纯化 特异性RNA剪接因子。(6)确定哪种蛋白质产品(S) 编码P细胞型阻遏子的P元件，(7)确定 P细胞型抑制因子发挥作用的机制。

The objective of this proposal is to further our understanding of the biology and regulation of P element, a transposable element found in Drosophila melanogaster. P elements are particularly interesting because their transposition is both genetically regulated (the P-M hybrid dygenesis syndrome) and tissue specific (transposition only occurs in the germline and not in somatic tissues). Recently we have shown that the germline specificity of P element transposition is regulated at the level of mRNA splicing. As a continuation of these studies we will: (1) Determine to the nucleotide which cis-acting sequences of the P element pre-mRNA transcript are required for the germline specificity. (2) Determine the spatial and developmental profile of the P element germline specific splice using a beta gal staining assay. (3) Genetically screen for mutants in the gene encoding the germline specific RNA splicing factor. (4) Attempt to isolate and maintain a Drosophila germline cell line that is capable of splicing the P element germline specific intron. (5) Attempt to establish an in vitro splicing system that will allow the biochemical identification and purification of the germline specific RNA splicing factor. (6) Identify which protein product(s) of P element encode the P cytotype repressor, (7) Determine the mechanism by which the P cytotype repressor functions.