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.
The authors declare no competing or financial interests.
A.C.N.K. designed and performed experiments. A.M.K. provided dissociated chromatophores and contributed to overall project strategy. R.T.H. and T.W.C. provided guidance, supervised the project and provided all laboratory resources.
This research was supported by the Office of Naval Research Basic Research Challenge [grant number N00014-10-0989] via a subcontract to T.W.C. and R.T.H.
Supplementary material available online at http://jeb.biologists.org/lookup/suppl/doi:10.1242/jeb.117945/-/DC1
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