Transforming the architecture of compound eyes
Transforming the architecture of compound eyes
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DOI：
10.1038/nature05128
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发表时间：
2006-10-12
期刊：
影响因子：
64.8
通讯作者：
Zuker, Charles S.
中科院分区：
文献类型：
--
作者：
Zelhof, Andrew C.;Hardy, Robert W.;Zuker, Charles S.
眼睛在动物王国中有明显的不同，是光探测和图像形成的多种解剖学解决方案进化的一个极端例子。所有光感受器细胞的一个显著特征是存在专门的隔室（脊椎动物中的圆盘外节和昆虫中的微绒毛横纹），其主要作用是容纳有效收集光子所需的数百万个光受体分子。在昆虫中，复眼可以有非常不同的内部结构（1-3）。果蝇和家蝇有一个开放的感杆系统，其中每个小眼的七个感杆节彼此分离，并作为独立的光导。相比之下，蜜蜂和各种蚊子和甲虫物种有一个封闭的系统，其中每个小眼内的感杆相互融合，因此共享相同的视轴。为了了解开放和封闭的横纹系统之间的过渡，我们分离和特点的作用，果蝇基因参与横纹肌装配。在这里，我们表明，Spacemaker，一种分泌的蛋白质，只在眼睛中表达的昆虫与开放的横纹系统，行为与Prominin和细胞粘附分子Chaoptin一起编排到一个开放的系统的横纹肌的分区。此外，spacemaker（spam）的完全丢失将开放的横纹肌系统转换为封闭的横纹肌系统，而其对封闭系统的光感受器的靶向表达显著地重组了复眼的结构，使其类似于开放系统。我们的研究结果提供了一个分子图谱的微绒毛组件的建设，并说明了在一个单一的结构蛋白的差异在形态发生的关键作用。
Eyes differ markedly in the animal kingdom, and are an extreme example of the evolution of multiple anatomical solutions to light detection and image formation. A salient feature of all photoreceptor cells is the presence of a specialized compartment ( disc outer segments in vertebrates, and microvillar rhabdomeres in insects), whose primary role is to accommodate the millions of light receptor molecules required for efficient photon collection. In insects, compound eyes can have very different inner architectures(1-3). Fruitflies and houseflies have an open rhabdom system, in which the seven rhabdomeres of each ommatidium are separated from each other and function as independent light guides. In contrast, bees and various mosquitoes and beetle species have a closed system, in which rhabdomeres within each ommatidium are fused to each other, thus sharing the same visual axis. To understand the transition between open and closed rhabdom systems, we isolated and characterized the role of Drosophila genes involved in rhabdomere assembly. Here we show that Spacemaker, a secreted protein expressed only in the eyes of insects with open rhabdom systems, acts together with Prominin and the cell adhesion molecule Chaoptin to choreograph the partitioning of rhabdomeres into an open system. Furthermore, the complete loss of spacemaker (spam) converts an open rhabdom system to a closed one, whereas its targeted expression to photoreceptors of a closed system markedly reorganizes the architecture of the compound eyes to resemble an open system. Our results provide a molecular atlas for the construction of microvillar assemblies and illustrate the critical effect of differences in a single structural protein in morphogenesis.