Molecular and structural characterization of photoreceptor cells in Annelida in order to utilise the photosensitive system as comparative character for inferring metazoan interrelationships

环节动物感光细胞的分子和结构表征，以便利用感光系统作为推断后生动物相互关系的比较特征

• 批准号: 5452245
• 负责人: Dr. Harald Hausen
• 金额: --
• 依托单位: Europäisches Laboratorium für Molekularbiologie (EMBL)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5452245?language=en
• 关键词: Molecular; structural; characterization; photoreceptor; cells

Comparative ultrastructural investigations revealed a high structural diversity of light sensitive organs, and of their photoreceptor cells. Conflicting views on photoreceptor cell type homology have since then prevented the usage of eyes for inferring phylogenies of higher rank taxa. A new comparative cell biological approach combining the ultrastructural and the molecular characterisation of cell types, however, now allows to trace the evolution of photoreceptor cells across Metazoa. This approach has so far revealed that the two morphologically different photoreceptor cell types, rhabdomeric and ciliary, are distinctly conserved in Bilateria. These types differ significantly in their ¿molecular fingerprint¿, which is the cell-type-specific deployment of opsins and other key molecules of the phototransduction cascade. The current project follows this new approach. Adding to their ultrastructural characterisation, we will determine the molecular fingerprint of diverse photoreceptor cells in a broad range of species, by cloning and in situ-localisation of opsins and G-alpha subunits of the phototransductory, heterotrimeric G-proteins. This will allow establishing robust homology hypotheses on light sensitive organs. In the first application period Annelida, with their great diversity in photoreceptors, are in focus. As a remote outgroup, we will include Branchiostoma, representing a suitable reference system for the identification of plesiomorphic characters. For the next application periods this approach will be extended to molluscs, plathelminthes, Tentaculata, and basal Deuterostomia to convey eyes into valuable characters for metazoan systematics.

比较超微结构的调查显示，光敏感器官的结构多样性高，他们的感光细胞。从那时起，对感光细胞类型同源性的否定观点阻止了使用眼睛来推断更高级别分类群的同源性。然而，一种新的比较细胞生物学方法结合了细胞类型的超微结构和分子特征，现在可以追溯整个后生动物感光细胞的进化。到目前为止，这种方法揭示了两种形态上不同的感光细胞类型，横纹肌和纤毛，是明显保守的Bilateria。这些类型在它们的分子指纹方面有显著差异，这是视蛋白和光转导级联的其他关键分子的细胞类型特异性部署。目前的项目遵循这一新的办法。添加到他们的超微结构特征，我们将确定不同的感光细胞在广泛的物种的分子指纹，通过克隆和原位定位的视蛋白和G-α亚基的光转导，异源三聚体G蛋白。这将允许在光敏器官上建立稳健的同源性假设。在第一个应用阶段，环节动物，与他们的光感受器的巨大多样性，是重点。作为一个遥远的外群，我们将包括Branchiostoma，代表一个合适的参考系统，用于识别的拟形字符。在接下来的应用阶段，这种方法将扩展到软体动物，plathelminthes，触手，和基础的Deuterostomia传达眼睛到有价值的字符后生动物系统学。