Meeting Abstract

48.6  Saturday, Jan. 5  Immunolabeling and diverse expression of opsin in the skin of the squid, Doryteuthis pealeii KINGSTON, A*; HANLON, RT; CRONIN, TW; University of Maryland, Baltimore County; Marine Biological Laboratory, Woods Hole, MA; University of Maryland, Baltimore County

Cephalopods, including squid, cuttlefish and octopus, have extraocular photoreceptors located in a variety of different tissues. Cephalopods have photoreceptors in the light organ, stellate ganglion and parolfactory vesicles, all of which operate using opsin. Here, we show that opsin is present in many skin regions of the squid, Doryteuthis pealeii (formerly Loligo pealeii), and propose a putative distributed photoreceptive system. RT-PCR revealed opsin transcripts in the retina, ventral mantle, ventral fin, arms 1-4, tentacle, and fin muscle tissue. All opsin transcripts are identical, based on predicted amino acid sequences. Further supporting a putative photoreceptive system, RT-PCR revealed the presence of retinochrome, a photoisomerase involved in chromophore recycling in the retina. Retinochrome was found in all tissue regions where opsin was located, and all retinochrome transcripts are identical, based on predicted amino acid sequences. Immunohistochemical staining shows that opsin protein is present in the outer segments of the retina, and in skin from the ventral mantle, dorsal mantle, and dorsal fin. These results lead us to hypothesize that the skin of D. pealeii may function as a distributed photoreceptive system. Future work will include immunohistochemistry for opsin and retinochrome on all untested regions of skin.