Kingston Alexandra C N, Kuzirian Alan M, Hanlon Roger T, Cronin Thomas W
Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
Marine Biological Laboratory, Woods Hole, MA 02543, USA.
J Exp Biol. 2015 May 15;218(Pt 10):1596-602. doi: 10.1242/jeb.117945.
Cephalopod mollusks are renowned for their colorful and dynamic body patterns, produced by an assemblage of skin components that interact with light. These may include iridophores, leucophores, chromatophores and (in some species) photophores. Here, we present molecular evidence suggesting that cephalopod chromatophores - small dermal pigmentary organs that reflect various colors of light - are photosensitive. RT-PCR revealed the presence of transcripts encoding rhodopsin and retinochrome within the retinas and skin of the squid Doryteuthis pealeii, and the cuttlefish Sepia officinalis and Sepia latimanus. In D. pealeii, Gqα and squid TRP channel transcripts were present in the retina and in all dermal samples. Rhodopsin, retinochrome and Gqα transcripts were also found in RNA extracts from dissociated chromatophores isolated from D. pealeii dermal tissues. Immunohistochemical staining labeled rhodopsin, retinochrome and Gqα proteins in several chromatophore components, including pigment cell membranes, radial muscle fibers, and sheath cells. This is the first evidence that cephalopod dermal tissues, and specifically chromatophores, may possess the requisite combination of molecules required to respond to light.
头足类软体动物以其色彩斑斓且动态变化的身体图案而闻名，这些图案由与光相互作用的一系列皮肤成分产生。这些成分可能包括虹彩细胞、白色素细胞、色素细胞以及（某些物种中的）发光器。在此，我们提供分子证据表明，头足类动物的色素细胞——能反射各种颜色光的小型皮肤色素器官——是光敏的。逆转录聚合酶链反应（RT-PCR）显示，在太平洋褶柔鱼、乌贼和罗氏乌贼的视网膜和皮肤中存在编码视紫红质和视黄醛色素异构酶的转录本。在太平洋褶柔鱼中，Gqα和鱿鱼瞬时受体电位（TRP）通道转录本存在于视网膜和所有皮肤样本中。在从太平洋褶柔鱼皮肤组织分离出的解离色素细胞的RNA提取物中也发现了视紫红质、视黄醛色素异构酶和Gqα转录本。免疫组织化学染色在色素细胞的几个组成部分中标记了视紫红质、视黄醛色素异构酶和Gqα蛋白，包括色素细胞膜、放射状肌纤维和鞘细胞。这是头足类皮肤组织，特别是色素细胞可能具备对光作出反应所需的必要分子组合的首个证据。
