Department of Biology, Center for Developmental Genetics, New York University, USA.
Dev Neurobiol. 2011 Dec;71(12):1212-26. doi: 10.1002/dneu.20905.
Color vision is found in many invertebrate and vertebrate species. It is the ability to discriminate objects based on the wavelength of emitted light independent of intensity. As it requires the comparison of at least two photoreceptor types with different spectral sensitivities, this process is often mediated by a mosaic made of several photoreceptor types. In this review, we summarize the current knowledge about the formation of retinal mosaics and the regulation of photopigment (opsin) expression in the fly, mouse, and human retina. Despite distinct evolutionary origins, as well as major differences in morphology and phototransduction machineries, there are significant similarities in the stepwise cell-fate decisions that lead from progenitor cells to terminally differentiated photoreceptors that express a particular opsin. Common themes include (i) the use of binary transcriptional switches that distinguish classes of photoreceptors, (ii) the use of gradients of signaling molecules for regional specializations, (iii) stochastic choices that pattern the retina, and (iv) the use of permissive factors with multiple roles in different photoreceptor types.
颜色视觉存在于许多无脊椎动物和脊椎动物物种中。它是一种基于独立于强度的光发射波长来区分物体的能力。由于它需要比较至少两种具有不同光谱敏感度的光感受器类型，因此这个过程通常由几种光感受器类型组成的镶嵌物介导。在这篇综述中，我们总结了目前关于视网膜镶嵌物形成和在果蝇、小鼠和人视网膜中光色素（视蛋白）表达的调控的知识。尽管在进化起源、形态和光转导机制方面存在显著差异，但在从祖细胞到表达特定视蛋白的终末分化光感受器的逐步细胞命运决定方面存在显著相似性。共同的主题包括：(i) 使用二进制转录开关来区分光感受器的类别，(ii) 利用信号分子的梯度进行区域特化，(iii) 随机选择模式化视网膜，以及 (iv) 使用在不同光感受器类型中具有多种作用的许可因子。
