FUNCTION OF THE E2F TRANSCRIPTION FACTOR

本研究旨在研究E2 F的功能。 转录因子 E2 F是一种异源二聚体因子， 由DP-1（或DP-1相关基因）编码的多肽和多肽 由E2 F-1（或E2 F-1相关基因）编码。 对哺乳动物细胞的研究表明 E2 F在G1期向S期的转化过程中起重要作用。 细胞周期 E2 F结合位点存在于几个启动子中， 其表达与细胞增殖有关的基因。 分析 这些启动子中的几个表明E2 F位点赋予转录 在细胞周期的特定时间激活。 在正常细胞中E2 F 活性受细胞周期蛋白依赖性激酶的阶段性激活调节 (cdk的），并提供了细胞周期进展和 特定的转录事件。 在组织培养细胞中， E2 F的作用很有趣。 E2 F-1基因的过度表达， 已发现将静止细胞驱动到S期并阻止循环细胞 退出细胞周期。 长期的结果显然是 这取决于所用的细胞类型; E2 F-1的高水平表达已经被证实， 显示转化一些永生化细胞系并引起凋亡细胞 别人的死亡。 我们建议研究E2 F活性的体内功能和调节。 我们的目标是确定E2 F在细胞增殖中的作用， 在正常发育过程中的分化，并确定重要特征 为规范这一职能。 这些研究将在 果蝇使用我们最近克隆的dE 2F和dDP同源物， 我们最近发现的一系列dE 2F突变体。 的 哺乳动物E2 F和DP基因的广泛家族似乎在功能上是 在果蝇中被每种类型的一个基因取代。 这便于 研究E2 F功能的实验在哺乳动物中是不可能的， 细胞 本提案的目标是：首先确定dE 2F的时间和地点 和DDP在发育过程中表达，并将其与 E2 F转录活性的出现;第二，为了研究E2 F的转录活性， E2 F的生物学作用，通过研究dE 2F缺失的后果 在整个开发过程中发挥作用;第三，执行结构/功能 通过检测dE 2F突变体在动物中的活性来分析dE 2F基因 第四，研究dE 2F活性的调节 通过分析dE 2F与功能相关基因的相互作用。

The research in this grant investigates the function of the E2F transcription factor. E2F is a heterodimeric factor composed of a polypeptide encoded by DP-1 (or DP-1-related genes) and a polypeptide encoded by E2F-1 (or E2F-1-related genes). Studies in mammalian cells show that E2F plays an important role during progression rom G1 to S phase of the cell cycle. E2F binding sites are found inn the promoters of several genes whose expression is linked to cell proliferations. Analysis of several of these promoters suggest that the E2F sites confer transcription activation at specific times in the cell cycle. In normal cells E2F activity is regulated by the phasic activation of cyclin dependent kinases (cdk's) and provides a connection between cell cycle progression and specific transcriptional events. In tissue culture cells the deregulation of E2F has interesting effects. The overexpression of the E2F-1 gene has been found to drive quiescent cells into S-phase and prevent cycling cells from exiting the cell cycle. The long-term outcome of this apparently depends on the cell types used; high level expression of E2F-1 has been shown to transform some immortalized cell lines and to cause apoptotic cell death in others. We propose to study the in vivo function and regulation of E2F activity. Our goal is to determine the role of E2F in cell proliferation and differentiation during normal development and identify features important for the regulation of this function. These studies will be carried out in Drosophila using the dE2F and dDP homologs that we have recently cloned and the series of dE2F mutants that we have recently identified. The extensive families of mammalian E2F and DP genes appear to be functionally replaced in Drosophila by one gene of each type. This facilitates experiments into the function of E2F that are not possible in mammalian cells. The objectives of this proposal are; first to determine when and where dE2F and dDP are expressed during development and to compare this with the appearance of E2F transcriptional activity; second, to investigate the biological role of E2F by studying the consequences of loss of dE2F function throughout development; third, to perform a structure/function analysis of dE2F gene by testing the activities of dE2F mutants in animals deficient for E2F; fourth, to investigate the regulation of dE2F activity by analyzing dE2F interactions with functionally related genes.