TRANSCRIPTIONAL REGULATORY MECHANISMS DURING DEVELOPMENT

描述(改编自申请者摘要)：胚胎调节其 在许多方面的生长和发育，但控制基因转录 是引导细胞沿着不同方向移动的最重要的方法之一 发育途径。在果蝇中，核调控的级联 事件通过产生细胞命运建立了非常早期的差异 错综复杂的基因表达模式。许多这样的图案形成 基因编码DNA结合蛋白，DNA结合蛋白相互调节 表达，并随后以一种方式指示基因组的其余部分 与生物体中的每个位置相适应。最近的证据表明 这些调节蛋白中的许多都是保守的 苍蝇和人类之间的进化距离，两者都是从 一级结构，意味着在机制上相似，并且，至少 在某种程度上，就它们的发展意义而言，也就是说， 嵌入它们的监管方案解决了常见的问题 一个发育中的多细胞有机体。因此，一个详细的 对一个系统中保守调节子相互作用的理解 可能对他们在其他领域的同源基因有重要的影响 系统。 在胚胎发生的研究中似乎有一个转折点 重要的是建立两种类型的具体机制。首先，哪一个 基因产物与哪些其他基因或基因产物直接相互作用； 第二，这些分子的具体后果是什么？ 互动。这项建议将有助于理解 通过重点研究两个因素的相互作用和作用的机制 同源结构域(HD)包含转录调节因子，参与 果蝇的图案形成。一种，渐进式(EN)，激活它自己的 基因，并在胚胎中抑制其他几个基因，并已被证明 在培养细胞中具有转录抑制活性。这个 另一种，FTZ，激活了许多基因，包括它自己的(FTZ)，在 被认为是直接的互动，并拥有强大的 培养细胞的转录激活功能。一种嵌合蛋白 其中EN HD被FTZ HD取代，就像EN一样，表现为 培养细胞中的抑制子。当这种蛋白质在胚胎中表达时， 它与FTZ基因相互作用，抑制它。通过解剖 对两个特定交互的要求，由EN本身激活 FTZ基因及其嵌合蛋白对其的抑制作用 将解决这个问题，即含有HD的靶基因如何 调节子在果蝇胚胎中被识别和控制，并且 从而阐明了复合体中转录调控的机制 发展环境。

DESCRIPTION (Adapted from Applicant's Abstract): Embryos regulate their growth and development in many ways, but control of gene transcription is one of the most important for directing cells along different developmental pathways. In Drosophila, a cascade of nuclear regulatory events establishes very early differences in cell fates by producing intricate patterns of gene expression. Many of these pattern forming genes encode DNA binding proteins which regulate each other's expression, and subsequently instruct the rest of the genome in a manner appropriate to each position in the organism. Recent evidence suggests that many of these regulatory proteins are conserved across the evolutionary distance separating flies and humans, both in terms of primary structure, implying similarity in mechanism, and, at least to some extent, in terms of their developmental "meaning", that is, how the regulatory scheme in which they are embedded solves the common problems of a developing multi-cellular organism. Therefore, a detailed understanding of the interactions of conserved regulators in one system is likely to have important implications for their homologs in other systems. There appears to be a juncture in the study of embryogenesis where it is important to establish specific mechanisms of two types. First, which gene products interact directly with which other genes or gene products; and second, what are the specific molecular consequences of those interactions. This proposal will contribute to the understanding of such mechanisms by focusing on the interactions and function of two homeodomain (HD) containing transcriptional regulators involved in pattern formation in Drosophila. One, Engrailed (En), activates its own gene and represses several other genes in embryos, and has been shown to possess a transcriptional repression activity in cultured cells. The other, Ftz, activates a number of genes, including its own (ftz), in an interaction that is thought to be direct, and possesses a strong transcription activation function in cultured cells. A chimeric protein in which the En HD is replaced by the Ftz HD, like En, behaves as a repressor in cultured cells. When this protein is expressed in embryos, it interacts with the ftz gene, repressing it. By dissecting the requirements for two specific interactions, activation by En of its own gene and repression of the ftz gene by the chimeric protein, this study will address the question of how the target genes of HD-containing regulators are recognized and controlled in Drosophila embryos and thereby elucidate mechanisms of transcriptional regulation in a complex developmental environment.