In the years following the publication of ‘A photoactivatable green-fluorescent protein from the phylum Ctenophora’ [1], another research group [2] sequenced hydrozoan (Cnidaria) fluorescent proteins that were very similar to those we cloned from cDNA prepared from ctenophore specimens. We therefore now believe that the green-fluorescent proteins reported in our study are not from ctenophores, and were due to incorporation of cnidarian prey into the ctenophore tissues.
Although our genes were cloned from two independent samples of mRNA taken years apart, the similarity of our sequences to those obtained from a siphonophore (Cnidaria, Hydrozoa) indicate that this mRNA was carried over from ingested material. This ctenophore species is known to prey on cnidarians, but we did not expect that mRNA would persist for as long as it did, and we regret our erroneous conclusion.
What is remarkable about this situation is that the ctenophore, in addition to maintaining full-length mRNA for the fluorescent protein, also incorporated the proteins into its tissue to the extent that its bioluminescence emission was green-shifted. While the exact species of origin for these proteins is unknown, the photoactivatable properties of this fluorescent protein are as originally described, and it remains an interesting target for future research and application.
Steven H. D. Haddock
Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road,
Moss Landing, CA 95039, USA
e-mail: haddock@mbari.org
Nadia Mastroianni
Axxam SpA, San Raffaele, Biomedical Science Park, via Olgettina 58,
20132 Milan, Italy
e-mail: Na_mastro@yahoo.it
Lynne M. Christianson
Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road,
Moss Landing, CA 95039, USA
e-mail: lynne@mbari.org
References
- 1.Haddock SHD, Mastroianni N, Christianson LM. 2010. A photoactivatable green-fluorescent protein from the phylum Ctenophora. Proc. R. Soc. B 277, 1155–1160. ( 10.1098/rspb.2009.1774) [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
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