Bicoid: A new addition to the body plan of Drosophila

Bicoid：果蝇身体计划的新成员

• 批准号: 6582048
• 负责人: Claude Desplan
• 金额: $ 28.26万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6582048
• 关键词: DNA footprinting; Drosophilidae; biochemical evolution; body regions; developmental genetics; gene expression; molecular cloning; molecular genetics; morphology; polymerase chain reaction; protein protein interaction; transcription factor; yeast two hybrid system

DESCRIPTION (provided by applicant): Although the Bicoid morphogen (Bcd) plays a pivotal role in patterning the anterior of the Drosophila (Dm) embryo, no bed homologue has been found outside Diptera. Here, we propose that the conserved hunchback (hb), orthodenticle (otd), and caudal (cad) are the key components of an ancestral anterior patterning system whose function has been taken over by bed in Dm. We will ask whether these genes can act together in Dm to control axial patterning in the absence of bcd. We will also study these genes in the wasp Nasonia vitripenis (Nv) where a mutation in hb produces a very severe anterior phenotype, consistent with our hypothesis that hb was originally necessary for extensive control of axial patterning. The morphological similarity of Nv embryogenesis to that of Dm will facilitate comparative studies. These studies in Dm and Nv will help us understand the changes underlying the acquisition of regulatory functions by the recently evolved Bcd. In parallel, we will study the molecular function of Hb, characterizing its physical interactions with itself and with Cad identified in a yeast two-hybrid screen. Aim 1 We will continue our study of Hunchback as a morphogen, including a study of its synergy with Bcd, as well as its ability to dimerize. As Dm hb might have lost functions that have been taken over by bed, we will study in Dm the patterning properties of Nv hb and of hb genes from a phylogenetic spectrum of species. To understand Nv hb regulation, its promoter will be placed in Dm to test whether bed, hb, otd or cad controls it. Using a yeast two-hybrid screen, we have observed a molecular interaction between Hb molecules. We will investigate the function of this dimerization and address whether it is required for the ability of Hb to act as a represser, while its activation requires the interaction with Bcd (or with Otd?). Aim 2 We will study the potential of Otd as a morphogen, and test whether high levels of Otd, alone or in combination with Hb, can pattern the anterior of the embryo in the absence of bcd. We will clone Nv otd, study its expression pattern and phenotype using RNAi. and study its regulation by Nv hb, or by bcd, hb and otd when placed in Din. Finally, we will assess in Dm the patterning function of Otd proteins from species where bed does not exist. Aim 3 caudal is a posterior morphogen that must be eliminated at the anterior, through transnational control by Bcd, or by a possible direct antagonism between Hb and Cad proteins. We will study the genetics, biochemistry and mechanisms of the interaction between Hb and Cad as well as the evolution of the relative contribution of the two mechanisms in invertebrates. Our comparative studies in two model insects, using the power of Dm molecular genetics combined with the unique features of Nv, will allow us to document the ancestral anterior patterning system. We hope to reconstruct in Drosophila the ancestral mechanisms, to perform a "de-evolution" from the derived fly embryo and revive the more generic type of development in insects where bed might not have appeared to coordinate anterior patterning functions.

描述（由申请人提供）：尽管双聚体形态学（BCD）在对果蝇（DM）胚胎的前部模式中起着关键作用，但在双翅目以外没有发现床同源物。在这里，我们建议保守的驼背（HB），正畸形（OTD）和尾（CAD）（CAD）是祖先前构图系统的关键组成部分，其功能已在DM中通过床占用。我们将询问这些基因在没有BCD的情况下是否可以在DM中起作用以控制轴向图案。我们还将在WASP鼻虫玻璃体（NV）中研究这些基因，其中HB中的突变产生非常严重的前表型，这与我们的假设是HB最初对于广泛控制轴向图案的假设是必不可少的。 NV胚胎发生与DM的形态相似性将有助于比较研究。这些在DM和NV中的研究将有助于我们了解最近进化的BCD对监管功能采集的基础变化。同时，我们将研究Hb的分子功能，表征其与自身的物理相互作用以及在酵母两杂化筛选中鉴定的CAD。目标1我们将继续研究驼背作为形态学的研究，包括对其与BCD的协同作用以及二聚体的能力。由于DM HB可能失去了被床接管的功能，因此我们将在DM中研究NV Hb的模式特性和从物种的系统发育谱中的HB基因的模式特性。为了了解NV HB调节，其启动子将被放置在DM中，以测试BED，HB，OTD或CAD是否可以控制它。使用酵母两杂交筛选，我们观察到HB分子之间的分子相互作用。我们将研究此二聚化的功能，并解决HB充当阻遏物的能力是否需要它的功能，而其激活需要与BCD（或OTD？）的相互作用。 AIM 2我们将研究OTD作为形态学的潜力，并在没有BCD的情况下测试高水平的OTD是否可以单独或与HB结合使用胚胎的前部。我们将使用RNAi旋转NV OTD，研究其表达模式和表型。并研究NV HB的调节，或将BCD，HB和OTD放置在DIN中时。最后，我们将在DM中评估OTD蛋白的模式函数，而OTD蛋白来自不存在床的物种。 AIM 3尾尾是一种后形态，必须在前部，通过BCD或通过HB和CAD蛋白之间的直接拮抗作用来消除。我们将研究HB和CAD之间相互作用的遗传学，生物化学和机制，以及两种机制在无脊椎动物中的相对贡献的演变。我们在两种模型昆虫中的比较研究，使用DM分子遗传学的功率与NV的独特特征相结合，将使我们能够记录祖先的前构图系统。我们希望在果蝇中重建祖先机制，从衍生的蝇胚胎中执行“脱进化”，并在昆虫中恢复更通用的发育类型，在昆虫中，床似乎似乎没有协调前部模式功能。