D-raf in Drosophila Signal Transduction

本研究的目的是明确D-raf在受体酪氨酸激酶介导的信号通路中的作用机制，以建立和阐述果蝇的模式。 使用的结构/功能的方法，我们已经定义了D-raf的调节结构域所需的信号在母体躯干途径，以指定细胞的命运在胚胎两极。 我们的研究表明，终端信号的传输取决于一个新的调节分支的活动，称为“抑制分支”，其中（i）与躯干受体酪氨酸激酶平行作用;（ii）是依赖于母体活动的躯干和fs（1）极孔基因;和（iii）涉及调节D-raf在丝氨酸残基388。 本项目的具体目标如下：（1）通过表达D-raf结构域来确定躯干和果蝇EGFR通路中调控机制的异同。 (2)以开始饱和筛选影响末端信号传导途径的“抑制性分支”的突变。 (3)使用含有丝氨酸388的D-rafCR 2模块（保守区2）完成双杂交筛选，以鉴定与D-raf相互作用的“抑制性分支”因子。 由于D-raf是原癌基因Raf-1在果蝇中的同源物，因此，表征其在发育中的作用并鉴定其调控机制将为理解高等生物中的信号转导过程提供线索。

The goal of this project is to define the mechanisms that regulate the activity of D-raf in receptor tyrosinekinase mediated signaling pathways for the establishment and elaboration of pattern in Drosophila melanogaster. Using a structure/function approach we have defined D-raf regulatory domains that are required for signaling in the maternal Torso pathway to specify cell fates at the embryonic poles. Our studies have revealed that transmission of the terminal signal depends on the activity of a novel regulatory branch, termed the "inhibitory branch", which (i) acts in parallel with the Torso receptor tyrosine kinase: (ii) is dependent on the maternal activities of the trunk and fs(1) pole hole genes; and (iii) involves the regulation of D-raf at serine residue 388. The specific aims of this project are as follows: (1) to define similarities and differences in mechanisms of regulation by expressing D-raf domains in Torso and Drosophila EGFR pathways. (2) to begin a saturation screen for mutations affecting the "inhibitory branch" of the terminal signaling pathway. (3) to complete a two-hybrid screen using the D-rafCR2 module (conserved region 2) containing serine 388 to identify "inhibitory branch" factor(s) that interact with D-raf. Since D-raf is the Drosophila homologue of the Raf-1 proto-oncogene, characterization of its role in development and identification of the mechanisms involved in its regulation will provide clues to understand the process of signal transduction in higher organisms.