The ancestry of deuterostome photoreceptors - molecular and structural investigations in echinoids and enteropneusts

分子和结构数据的整合为动物光感受器细胞的进化和功能提出了新的有趣的见解，并推翻了几个传统的进化假说。很明显，在动物进化的早期，视蛋白发生了分化，产生了几种不同的视蛋白和光感受器细胞类型，它们具有自己的功能特异性。光感受器细胞类型特定的细胞命运集合的存在证实了这一情景，这些特定的细胞命运决定了明显相关生物中的转录因子。甚至在脊椎动物及其近缘的被囊动物和头索动物中，最近也发现了许多新的视蛋白和光感受器细胞类型，并出现了一个令人兴奋的研究领域，涵盖了光感觉的生化、生理和发育方面。在应用合作项目中，我们的目标是通过将Opsins和其他分子光感受器细胞标记的基因表达研究与免疫组织化学和电子显微镜研究相结合，揭示这种观察到的多样性的进化根源。对最近测序的紫棘球绦虫和科瓦列夫斯基肠炎杆菌的基因组进行分析，发现这些动物中存在几种不同的视蛋白类型。通过我们的综合方法，我们将鉴定和表征各自的光感受器细胞，并深入了解各种后口类光感受器的进化起源和祖先功能。

The integration of molecular and structural data put forth new intriguing insights into evolution and function of animal photoreceptor cells and overrode several traditional evolutionary hypotheses. It became clear that opsins diverged early during animal evolution giving rise to several distinct opsin and photoreceptor cell types with own functional specifity. This scenario is corroborated by the existence of photoreceptor cell type specific sets of cell fate determining transcription factors in distinctly related organisms. Even in vertebrates and the allied tunicates and cephalochordates numerous new opsins and photoreceptor cell types were recently found and an exciting research field arose covering biochemical, physiological and developmental aspects of light sensation. In the applied collaborative project we aim to uncover the evolutionary roots of this observed diversity by combining gene expression studies of opsins and other molecular photoreceptor cell markers with immunohistochemical and electron microscopic investigations in basal deuterostomes. Analysis of the recently sequenced genomes of the echinoid S. purpuratus and the enteropneust S. kowalevskii uncovered the existence of several different opsin types in these animals. With our integrate approach we will identify and characterize the respective photoreceptor cells and get deep insights into the evolutionary origin and ancestral function of various types of deuterostome photoreceptors.