About the Cover
Cover
Amphioxus, or lancelets, are invertebrate chordates with most common members in the genus Branchiostoma. These animals live burrowed in relatively shallow marine sediments, typically positioned with the anterior end of the body within the burrow mouth, where it is exposed to downwelling visible and ultraviolet light. Under white light amphioxus is whitish-translucent (cover micrograph, left), but Dimitri D. Deheyn and his collaborators found that it becomes brightly fluorescent under blue light; in adults this fluorescence is mainly confined to the anterior end of the body (cover micrograph, right).
In pages 95 to 100 of this issue, the authors show that some of the anterior tissues in three amphioxus species-one each from Florida, France, and Japan-emit conspicuous green fluorescence. They discovered that the fluorescence of one species (B. floridae) is due to an endogenous green fluorescent protein (GFP) that they named AmphiGFP. Phylogenetic analyses show that AmphiGFP is homologous to the GFP otherwise found only in Cnidaria and in some copepod crustaceans. This broad phylogenetic span suggests that many other animals with GFPs probably remain to be found. It also raises the possibility that GFP could have functions far more diverse than producing light by fluorescence, perhaps including photoreception and photo-protection.
Credits: Photo, Dimitri D. Deheyn (Scripps Institution of Oceanography); cover layout, Beth Liles (Marine Biological Laboratory).
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Copyright © 2007 by the Marine Biological Laboratory.
