Patterning and morphogenesis of the insect head - origin of epicranial sutures and Tc-homeobrain

昆虫头部的图案和形态发生 - 颅骨缝和 Tc-homeobrain 的起源

• 批准号: 226547032
• 负责人: Professor Dr. Gregor Bucher
• 金额: --
• 依托单位: Abteilung Evolutionäre Entwicklungsgenetik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/226547032?language=en
• 关键词: Patterning; morphogenesis; insect; head; origin

Insect head morphology is extremely diverse and many crucial adaptations to different life styles have shaped the anatomy of insect heads (e.g. predating, licking on rotten fruit, sucking blood). It is a composite structure built by several segments and non-segmental tissue and it is formed by complex morphogenetic movements. Several sutures mark the insect head, which function in stabilization of the head capsule, in muscle attachment or ecdysis. It is well accepted that most of the sutures do not reflect segment boundaries, but their developmental and evolutionary origin remains obscure. Anterior insect head patterning does not involve pair rule or Hox cluster gene expression. Hence, it must be different from the trunk but the gene regulatory network of head patterning remains poorly understood. Strikingly, a set of highly conserved genes pattern the anterior region of all bilaterian animals. We use the red flour beetle Tribolium castaneum with its insect typical non-involuted head as a model for understanding the development of an insect head and the underlying genetic principles. The insights we gather in Tribolium are compared to Drosophila, other insects and arthropods and also vertebrates in order to trace back the evolution of anterior patterning. In the past, we have identified novel genes required for head pattern formation and have established a provisional fate map of the head. The latter led us to propose the hypothesis that the coronal and frontal sutures (the lines of ecdysis) are derived from embryonic epithelial fusion events. In this project, we want to perform in vivo imaging and non-invasive marking of cells with fluorescent proteins in order to generate an exact fate map and to better understand the morphogenetic movements of the head. Using these tools, we will then test, whether the sutures do indeed derive from embryonic fusion events. Further, we want to analyze the function of Tc-homeobrain, a novel head patterning gene, which is expressed in an anterior cap in the early blastoderm and later in the head anlagen. This is similar to Drosophila indicating a conserved function. However, no functional data is available in the fly. In RNAi in Tribolium, the entire dorsal head is missing. Several transgenic lines will be constructed as part of this project, which will be valuable for other studies. This includes a system to genetically permanently mark epidermal cells, several Gal4 drivers and responder constructs with fluorescent proteins, which mark nuclei or cell outlines.

昆虫头部形态极其多样，许多对不同生活方式的重要适应塑造了昆虫头部的解剖结构（例如捕食，舔腐烂的水果，吸血）。它是由多个节段和非节段组织组成的复合结构，是由复杂的形态发生运动形成的。昆虫头部有几条缝线，其作用是稳定头囊、肌肉附着或蜕皮。人们普遍认为，大多数的缝合线不反映节的边界，但他们的发展和进化的起源仍然不清楚。昆虫头部前部的模式化不涉及配对规则或Hox簇基因表达。因此，它必须不同于躯干，但头部模式的基因调控网络仍然知之甚少。引人注目的是，一组高度保守的基因模式所有两侧对称动物的前部区域。 我们使用赤拟谷盗（Tribolium castaneum）及其昆虫典型的非内卷头部作为模型，以了解昆虫头部的发育和潜在的遗传原理。我们在赤拟谷盗中收集的见解与果蝇、其他昆虫和节肢动物以及脊椎动物进行了比较，以追溯前部图案的进化。在过去，我们已经确定了新的基因所需的头部模式的形成，并建立了一个临时的命运地图的头部。后者使我们提出假设，冠状缝和额缝（蜕皮线）来自胚胎上皮融合事件。在这个项目中，我们希望用荧光蛋白对细胞进行体内成像和非侵入性标记，以生成精确的命运图，并更好地了解头部的形态发生运动。使用这些工具，我们将测试缝合是否确实来自胚胎融合事件。此外，我们想分析的功能的Tc-homeobrain，一种新的头部图案的基因，这是在前帽中的早期胚盘和后来在头部原基中表达。这与果蝇相似，表明具有保守的功能。然而，在飞行中没有可用的功能数据。在Tribolium的RNAi中，整个背头缺失。本研究将构建几个转基因株系，这将对其他研究具有参考价值。这包括一个系统，以遗传永久标记表皮细胞，几个Gal 4驱动程序和响应结构与荧光蛋白，标记细胞核或细胞轮廓。