乌贼的眼睛,章鱼,墨鱼是进化趋同的教科书例子,由于它们与脊椎动物的惊人相似性。出于这个原因,对头足类的感光和视觉的研究对于更广泛的受众来说很重要。以前的研究表明,基因如pax6,或某些视蛋白编码基因,在进化上高度保守,并在远程相关的双边体的个体发育过程中发挥类似的作用。在这项研究中,鉴定和表征编码光敏蛋白和Reflectins的基因。视紫红质的表达模式,Xenopsin,视网膜色素,通过原位杂交实验,在侏儒鱿鱼Xipholeptosnotoides的发育胚胎中观察到了两个反射蛋白基因。视紫质不仅在X的视网膜中表达。后者是一种头足类脱形。这两种反射素基因都在眼睛和嗅觉器官中表达。这些发现证实了先前的研究,即在各种头足类动物的眼睛和几个眼外组织的转录组中发现了视蛋白基因。视紫红质的表达,Xenopsin,视网膜色素,嗅觉器官中的两个反射蛋白基因是一个迄今尚未被描述的发现。在其他生物中,已经表明,由于两种分子彼此依赖视网膜异构化,所以视黄质色素和视紫质蛋白必然彼此相关。此外,我们证明视网膜色素在X.notoides的视网膜和嗅觉器官中表达。这项研究显示了许多新的编码视蛋白的基因在器官中的表达模式,这些基因以前与光接收无关。这表明视蛋白可能不仅参与光接收,或者嗅觉器官等器官也参与光接收。
The eyes of squids, octopuses, and cuttlefish are a textbook example for evolutionary convergence, due to their striking similarity to those of vertebrates. For this reason, studies on cephalopod photoreception and vision are of importance for a broader audience. Previous studies showed that genes such as pax6, or certain opsin-encoding genes, are evolutionarily highly conserved and play similar roles during ontogenesis in remotely related bilaterians. In this study, genes that encode photosensitive proteins and Reflectins are identified and characterized. The expression patterns of rhodopsin, xenopsin, retinochrome, and two reflectin genes have been visualized in developing embryos of the pygmy squid Xipholeptos notoides by in situ hybridization experiments. Rhodopsin is not only expressed in the retina of X. notoides but also in the olfactory organ and the dorsal parolfactory vesicles, the latter a cephalopod apomorphy. Both reflectin genes are expressed in the eyes and in the olfactory organ. These findings corroborate previous studies that found opsin genes in the transcriptomes of the eyes and several extraocular tissues of various cephalopods. Expression of rhodopsin, xenopsin, retinochrome, and the two reflectin genes in the olfactory organ is a finding that has not been described so far. In other organisms, it has been shown that Retinochrome and Rhodopsin proteins are obligatorily associated with each other as both molecules rely on each other for Retinal isomerisation. In addition, we demonstrate that retinochrome is expressed in the retina of X. notoides and in the olfactory organ. This study shows numerous new expression patterns for Opsin-encoding genes in organs that have not been associated with photoreception before, suggesting that either Opsins may not only be involved in photoreception or organs such as the olfactory organ are involved in photoreception.