Major colour patterns of reef-building corals are due to a family of GFP-like proteins

Abstract

Reef-building corals are renowned for their brilliant colours yet the biochemical basis for the pigmentation of corals is unknown. Here, we show that these colours are due to a family of GFP-like proteins that¯uoresce under ultraviolet (UV) or visible light. Pigments from ten coral species were almost identical to pocilloporin (Dove et al. 1995) being dimers or trimers with approximately 28-kDa subunits. Degenerative primers made to common N-terminal sequences yielded a complete sequence from reef-building coral cDNA, which had 19.6% amino acid identity with green¯uo-rescent protein (GFP). Molecular modelling revealed a`b-can' structure, like GFP, with 11 b-strands and a completely solvent-inaccessible¯uorophore composed of the modi®ed residues Gln-61, Tyr-62 and Gly-63. The molecular properties of pocilloporins indicate a range of functions from the conversion of high-intensity UV radiation into photosynthetically active radiation (PAR) that can be regulated by the dino¯agellate peridininchlorophyll-protein (PCP) complex, to the shielding of the Soret and Q x bands of chlorophyll a and c from scattered high-intensity light. These properties of pocilloporin support its potential role in protecting the photosynthetic machinery of the symbiotic dino¯agel-lates of corals under high light conditions and in enhancing the availability of photosynthetic light under shade conditions.

Corals from the Persian/Arabian Gulf as models for thermotolerant reef-builders: Prevalence of clade C3 Symbiodinium, host fluorescence and ex situ temperature tolerance

“…Our results demonstrate clearly that FP fluorescence of P. lobata can be used for non-invasive optical monitoring of the stress response of the host tissue. Regarding the putative photoprotective function of GFP-like proteins (Dove et al, 2001;Salih et al, 2000;Wiedenmann et al, 1999), the consistent downregulation under heat stress does not support any superior FP-mediated protection of the experimental Abu Dhabi specimens.…”

“…These host pigments belong to the family of GFP-like proteins (Alieva et al, 2008;Dove et al, 2001;Oswald et al, 2007;Wiedenmann et al, 2004Wiedenmann et al, , 2009) of which several (but not all) are regulated at transcriptional level in reef corals in response to changes in environmental conditions; in particular by blue light (Bay et al, 2009;D'Angelo et al, 2008;Desalvo et al, 2008;Leutenegger et al, 2007;Smith-Keune and Dove, 2007). Only recently, the expression of red FPs in the growth zones, wounded or epibiont-infested colony parts of P. lobata was correlated with areas characterised by accelerated cell proliferation .…”

“…The heat stress tolerance of corals could potentially be supported at different levels, for instance by the protection of cellular components through an enhanced antioxidant defense (Lesser, 1996) or elevated level of heat shock proteins (Choresh et al, 2004) or by higher levels of photoprotective substances such as mycosporine-like amino acids (Dunlap and Shick, 1998) or green fluorescent protein (GFP)-like pigments (Dove et al, 2001;Salih et al, 2000). Yet another strategy might be to host symbiont communities dominated by thermotolerant symbionts, either by the uptake of new symbionts after a bleaching event or by changing the relative abundance of symbiont types already present in the host (symbiont shuffling) (Baker, 2001;Baker et al, 2004;Berkelmans and van Oppen, 2006;Buddemeier and Fautin, 1993;Jones et al, 2008;Rowan et al, 1997).…”

Locally accelerated growth is part of the innate immune response and repair mechanisms in reef-building corals as detected by green fluorescent protein (GFP)-like pigments

“…The pigments responsible for the pink-blue pigmentation of reef coral response belong to the family of GFP-like proteins (Dove et al 2001;Wiedenmann et al 2004bWiedenmann et al , 2009Oswald et al 2007;Alieva et al 2008;D'Angelo et al 2008). Based on their photophysical properties, they can be divided into two major groups: the fluorescent proteins (FPs), emitting photons in the spectral range from cyan to red upon stimulation with light of suitable wavelengths, and the non-fluorescent chromoproteins (CPs), which display bright purple to blue colours (Prescott et al 2003;Alieva et al 2008;Nienhaus and Wiedenmann 2009).…”

Characterisation of coral explants: a model organism for cnidarian–dinoflagellate studies

“…Finer detail showed that the symbiotic zooxanthellae (Zs) were encased in host 318 endodermal tissue (En), a feature common with whole corals ). This comparable cell 319 type composition provides a better means for investigating how nutrients and carbon are transferred 320 between the host and symbiont at a microscale ( In some instances they are proposed to do both, depending on the position of the fluorescent pigment 330 relative to the zooxanthellae (Dove et al 2001). In present study, it is possible that they fulfil a dual 331 role, as the explants were grown at relatively low light, and showed relative sensitivity to very high 332 light (Fig.…”