Visual phototransduction components in cephalopod chromatophores suggest dermal photoreception

Journal article

Kingston, Alexandra C. N.; Kuzirian, Alan M.; Hanlon, Roger T.; Cronin, Thomas W.
Journal of Experimental Biology (2015)

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, Gqa and squid TRP channel transcripts were present in theretina and in all dermal samples. Rhodopsin, retinochrome and Gqa transcripts were also found in RNA extracts from dissociated chromatophores isolated from D. pealeii dermal tissues. Immunohistochemical staining labeled rhodopsin, retinochrome and Gqa 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.