Evolution of mRNA localization and the role of localized determinants in posterior patterning and growth zone determination of two short germ insects

胚胎极性的建立是所有动物早期发育的关键一步。在长胚芽昆虫果蝇中，这主要是通过将特定的mRNAs定位到卵母细胞的一极或两极来实现的。虽然在果蝇中，母体基因产物的定位机制已经被很好地理解，但尚不清楚在短生殖性昆虫中，mRNA的定位是否或在多大程度上有助于轴的形成。因此，我们将研究和比较两个新出现的模型系统中的mRNA定位机制：面粉甲虫Tribolium Castaneum和马利筋虫OnCopeltus Fasciatus。此前，我们已经证明，在这两种生物中，AP图案级联的母体启动与果蝇非常不同。为了对昆虫轴向图案的进化有更多的了解，我们将测试候选(来自果蝇和线虫)卵的早期极化和轴图案，并进行实验以确定新的、可能较短的细菌特定因素。此外，我们还会问，这些机制是否也参与了后来的重要步骤，包括生长带的形成和二次生长。该项目将由两名调查员进行，一名在埃尔兰根，一名在耶路撒冷。每个研究人员将专注于一个物种，并研究一系列潜在相关基因的模式和功能。此外，我们还将进行跨物种实验，也包括果蝇，测试机制是否保守到足以允许一个物种的基因在另一个物种中定位。该项目的协作和比较方面对于对昆虫发育的进化理解至关重要，并最终对于理解轴形成的进化至关重要。

Setting up embryo polarity is a crucial step in early development of all animals. In the long germ insect Drosophila, this is achieved mainly through the localization of specific mRNAs to one or both poles of the oocyte. While in Drosophila the mechanisms for localizing maternal gene products are well understood, it is unknown if or to which degree mRNA localisation contributes to axes formation also in short germ insects. Therefore, we will study and compare the mRNA localization mechanisms in two emerging model systems: the flour beetle Tribolium castaneum and the milkweed bug Oncopeltus fasciatus. Previously, we have shown that the maternal initiation of AP patterning cascades in both organisms is very different from Drosophila. To gain additional insights into the evolution of axial patterning in insects, we will test candidates (derived from Drosophila and C. elegans) for early polarisation and axis patterning of the egg, and carry out experiments to identify new, potentially short germ specific factors. In addition, we will ask whether these mechanisms are also involved in a later important step, including growth zone formation and secondary growth. The project will be carried out by two investigators, one in Erlangen and one in Jerusalem. Each investigator will focus on one species, and study the pattern and function of a series of potentially relevant genes. In addition we will carry out cross-species experiments, also involving Drosophila, testing whether the mechanisms are conserved enough to allow the localization of genes from one species in the other. The collaborative and comparative aspects of this project are crucial to an evolutionary understanding of insect development, and ultimately to an understanding of the evolution of axis formation.