TY - JOUR
T1 - Evidence for Multiple Phototransduction Pathways in a Reef-Building Coral
AU - Mason, Benjamin
AU - Schmale, Michael
AU - Gibbs, Patrick
AU - Miller, Margaret W.
AU - Wang, Qiang
AU - Levay, Konstantin
AU - Shestopalov, Valery
AU - Slepak, Vladlen Z.
N1 - Funding Information:
We gratefully acknowledge D. Williams, L. Johnston, and others for their assistance with fieldwork and larval culture, M. Medina for supplying larval RNA, I. Baums and N. Polato for sharing unpublished A. palmata transcriptome data, G. Gaidosh for help with confocal microscopy and imaging, R. Crouch (Medical University of South Carolina and NEI, National Institutes of Health) for providing 11-cis-retinal, D. Farrens for helpful discussions, and R. Albright for advice during preparation of this manuscript. This project was facilitated by permits FKNMS-2006-026, FKNMS-2009-022, FKNMS-2010-055, and support from the Florida Keys National Marine Sanctuary.
PY - 2012/12/5
Y1 - 2012/12/5
N2 - Photosensitive behaviors and circadian rhythms are well documented in reef-building corals and their larvae, but the mechanisms responsible for photoreception have not been described in these organisms. Here we report the cloning, immunolocalization, and partial biochemical characterization of three opsins and four G proteins expressed in planulae of the Caribbean elkhorn coral, Acropora palmata. All three opsins (acropsins 1-3) possess conserved seven-pass transmembrane structure, and localize to distinct regions of coral planulae. Acropsin 1 was localized in the larval endoderm, while acropsin 2 was localized in solitary cells of the ectoderm. These rod-like cells displayed a remarkably polarized distribution, concentrated in the aboral end. We also cloned four A. palmata G protein alpha subunits. Three were homologs of vertebrate Gi, Go, and Gq. The fourth is presumably a novel G protein, which displays only 40% identity with the nearest known G protein, and we termed it Gc for "cnidarian". We show that Gc and Gq can be activated by acropsins in a light-dependent manner in vitro. This indicates that at least acropsins 1 and 3 can form functional photoreceptors and potentially may play a role in color preference during settlement, vertical positioning and other light-guided behaviors observed in coral larvae.
AB - Photosensitive behaviors and circadian rhythms are well documented in reef-building corals and their larvae, but the mechanisms responsible for photoreception have not been described in these organisms. Here we report the cloning, immunolocalization, and partial biochemical characterization of three opsins and four G proteins expressed in planulae of the Caribbean elkhorn coral, Acropora palmata. All three opsins (acropsins 1-3) possess conserved seven-pass transmembrane structure, and localize to distinct regions of coral planulae. Acropsin 1 was localized in the larval endoderm, while acropsin 2 was localized in solitary cells of the ectoderm. These rod-like cells displayed a remarkably polarized distribution, concentrated in the aboral end. We also cloned four A. palmata G protein alpha subunits. Three were homologs of vertebrate Gi, Go, and Gq. The fourth is presumably a novel G protein, which displays only 40% identity with the nearest known G protein, and we termed it Gc for "cnidarian". We show that Gc and Gq can be activated by acropsins in a light-dependent manner in vitro. This indicates that at least acropsins 1 and 3 can form functional photoreceptors and potentially may play a role in color preference during settlement, vertical positioning and other light-guided behaviors observed in coral larvae.
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U2 - 10.1371/journal.pone.0050371
DO - 10.1371/journal.pone.0050371
M3 - Article
C2 - 23227169
AN - SCOPUS:84870784002
VL - 7
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 12
M1 - e50371
ER -