Bioluminescence is the production of visible light by living organisms. It occurs through the oxidation of luciferin substrates catalysed by luciferase enzymes. Auxiliary proteins, such as fluorescent proteins and luciferin-binding proteins, can modify the light emitted wavelength or stabilize reactive luciferin molecules, respectively. Additionally, calcium ions are crucial for the luminescence across various species. Despite the large phylogenetic distribution of bioluminescent organisms, only a few systems have been comprehensively studied. Notably, cnidarian species of the Renilla genus utilize a coelenterazine-dependent luciferase, a calcium-dependent coelenterazine-binding protein and a green fluorescent protein. We investigated the bioluminescence of three sea pen species: Pennatula phosphorea, Anthoptilum murrayi and Funiculina quadrangularis (Pennatuloidea, Anthozoa). Their light-emission spectra reveal peaks at 510, 513 and 485 nm, respectively. A coelenterazine-based reaction was demonstrated in all three species. Using transcriptome analyses, we identified transcripts coding for luciferases, green fluorescent proteins and coelenterazine-binding proteins for P. phosphorea and A. murrayi. Immunodetection confirmed the expression of luciferase in P. phosphorea and F. quadrangularis. We also expressed recombinant luciferase of A. murrayi, confirming its activity. We highlighted the role of calcium ions in bioluminescence, possibly associated with the mechanism of substrate release at the level of coelenterazine-binding proteins. The study proposes a model for anthozoan bioluminescence, offering new avenues for future ecological and functional research on these luminous organisms.

• Keywords
• Anthoptilidae, Funiculidae, Pennatulidae, bioluminescence, coelenterazine, luciferase, luciferin-binding protein, luminous system,
• MeSH
• Phylogeny MeSH
• Imidazoles metabolism   MeSH
• Anthozoa * genetics   metabolism   MeSH
• Luciferases metabolism   genetics   MeSH
• Luminescent Proteins metabolism   genetics   MeSH
• Luminescence MeSH
• Luminescent Measurements methods   MeSH
• Pyrazines metabolism   MeSH
• Gene Expression Profiling * MeSH
• Transcriptome * MeSH
• Green Fluorescent Proteins metabolism   genetics   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• coelenterazine MeSH Browser
• Imidazoles MeSH
• Luciferases MeSH
• Luminescent Proteins MeSH
• Pyrazines MeSH
• Green Fluorescent Proteins MeSH