|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Review |
Expression of pineal ultraviolet- and green-like opsins in the pineal organ and retina of teleosts
1 Department of Zoology, University of Lund, Lund, Sweden,
2 Institute of Marine Research, Austevoll Aquaculture Research Station, N-5392 Storebø, Norway,
3 Department of Pathology, University of Lund, Sölvegatan 25, 22185, Lund, Sweden and
4 Department of Molecular Biology, University of Bergen, Bergen, Norway
* Present address: Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada V5A 1S6
Author for correspondence at address 3 (e-mail: bo.holmqvist{at}pat.lu.se)
Accepted April 19, 2001
In teleostean bony fishes, studies on the adults of various species have shown that pineal photoreceptors are maximally sensitive to short- and middle-wavelength light, possibly utilising both rod-like and pineal-specific opsins. Until recently, however, very little was known about the pineal opsins present in embryonic and larval teleosts and their relationships to opsins expressed by retinal photoreceptors. Our immunocytochemical studies have revealed that, in Atlantic halibut, herring and cod, pineal photoreceptors express principal phototransduction molecules during embryonic life before they appear in retinal photoreceptors. In cDNA from embryonic and adult halibut, we identified two partial opsin gene sequences, HPO1 and HPO4, with highest homology to teleost green and ultraviolet cone opsins (72–83% and 71–83% amino acid identity, respectively). In halibut, these opsins are expressed in the pineal organ of embryos and appear in the retina of larvae. Our recent in situ hybridisation studies with RNA probes for HPO1 and HPO4 demonstrate the presence of green-like opsin mRNAs in the pineal organ and the retina of herring, cod, turbot, haddock, Atlantic salmon, zebrafish and three species of cichlid, and of ultraviolet opsins in the retinas of zebrafish, Atlantic salmon, turbot and the three cichlid species. We conclude that the halibut pineal organ appears to have the potential for both ultraviolet and green photosensitivity from the embryonic stage and that the retina may acquire the same potential during the larval stages. In the other teleosts studied, although both pineal and retinal photoreceptors seem to utilise a green-like opsin from the larval stage, ultraviolet photoreception appears to be restricted to the retina.
Key words: pineal organ, retina, fish, cloning, mRNA, in situ hybridisation.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
