Animals sense light primarily by an opsin-based photopigment present in a photoreceptor cell. Cnidaria are arguably the most basal phylum containing a well-developed visual system. The evolutionary history of opsins in the animal kingdom has not yet been resolved. Here, we study the evolution of animal opsins by genome-wide analysis of the cubozoan jellyfish Tripedalia cystophora, a cnidarian possessing complex lens-containing eyes and minor photoreceptors. A large number of opsin genes with distinct tissue- and stage-specific expression were identified. Our phylogenetic analysis unequivocally classifies cubozoan opsins as a sister group to c-opsins and documents lineage-specific expansion of the opsin gene repertoire in the cubozoan genome. Functional analyses provided evidence for the use of the Gs-cAMP signaling pathway in a small set of cubozoan opsins, indicating the possibility that the majority of other cubozoan opsins signal via distinct pathways. Additionally, these tests uncovered subtle differences among individual opsins, suggesting possible fine-tuning for specific photoreceptor tasks. Based on phylogenetic, expression and biochemical analysis we propose that rapid lineage- and species-specific duplications of the intron-less opsin genes and their subsequent functional diversification promoted evolution of a large repertoire of both visual and extraocular photoreceptors in cubozoans.

• MeSH
• AMP cyklický metabolismus   MeSH
• biologická evoluce * MeSH
• Cubozoa genetika   metabolismus   MeSH
• exprese genu MeSH
• fotoreceptory metabolismus   MeSH
• fylogeneze MeSH
• genom * MeSH
• genomika metody   MeSH
• mapování chromozomů MeSH
• messenger RNA genetika   MeSH
• multigenová rodina MeSH
• opsiny genetika   metabolismus   MeSH
• proteiny vázající GTP metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Animal eyes are morphologically diverse. Their assembly, however, always relies on the same basic principle, i.e., photoreceptors located in the vicinity of dark shielding pigment. Cnidaria as the likely sister group to the Bilateria are the earliest branching phylum with a well developed visual system. Here, we show that camera-type eyes of the cubozoan jellyfish, Tripedalia cystophora, use genetic building blocks typical of vertebrate eyes, namely, a ciliary phototransduction cascade and melanogenic pathway. Our findings indicative of parallelism provide an insight into eye evolution. Combined, the available data favor the possibility that vertebrate and cubozoan eyes arose by independent recruitment of orthologous genes during evolution.

• MeSH
• biologické modely MeSH
• Cercopithecus aethiops MeSH
• cilie metabolismus   ultrasonografie   MeSH
• COS buňky MeSH
• Cubozoa růst a vývoj   MeSH
• financování organizované MeSH
• fotoreceptory bezobratlých cytologie   metabolismus   ultrastruktura   MeSH
• krystaliny metabolismus   MeSH
• melaniny metabolismus   MeSH
• messenger RNA MeSH
• molekulární sekvence - údaje MeSH
• obratlovci růst a vývoj   MeSH
• oči cytologie   růst a vývoj   ultrastruktura   MeSH
• oční čočka metabolismus   MeSH
• pigmentace MeSH
• regulace genové exprese genetika   MeSH
• sekvenční homologie nukleových kyselin MeSH
• transkripční faktor spojený s mikroftalmií genetika   metabolismus   MeSH
• tyčinkové opsiny metabolismus   MeSH
• zrak genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

Cnidaria is the earliest-branching metazoan phylum containing a well-developed, lens-containing visual system located on specialized sensory structures called rhopalia. Each rhopalium in a cubozoan jellyfish Tripedalia cystophora has a large and a small complex, camera-type eye with a cellular lens containing distinct families of crystallins. Here, we have characterized J2-crystallin and its gene in T. cystophora. The J2-crystallin gene is composed of a single exon and encodes a 157-amino acid cytoplasmic protein with no apparent homology to known proteins from other species. The non-lens expression of J2-crystallin suggests nonoptical as well as crystallin functions consistent with the gene-sharing strategy that has been used during evolution of lens crystallins in other invertebrates and vertebrates. Although nonfunctional in transfected mammalian lens cells, the J2-crystallin promoter is activated by the jellyfish paired domain transcription factor PaxB in co-transfection tests via binding to three paired domain sites. PaxB paired domain-binding sites were also identified in the PaxB-regulated promoters of the J1A- and J1B-crystallin genes, which are not homologous to the J2-crystallin gene. Taken together with previous studies on the regulation of the diverse crystallin genes, the present report strongly supports the idea that crystallin recruitment of multifunctional proteins was driven by convergent changes involving Pax (as well as other transcription factors) in the promoters of nonhomologous genes within and between species as well as within gene families.

• MeSH
• buněčné linie MeSH
• Cercopithecus aethiops MeSH
• COS buňky MeSH
• Cubozoa genetika   metabolismus   MeSH
• cytoplazma metabolismus   MeSH
• exony MeSH
• financování organizované MeSH
• klonování DNA MeSH
• krystaliny genetika   chemie   metabolismus   MeSH
• lidé MeSH
• molekulární evoluce MeSH
• molekulární sekvence - údaje MeSH
• oční čočka metabolismus   MeSH
• promotorové oblasti (genetika) MeSH
• regulace genové exprese MeSH
• sekvence nukleotidů MeSH
• transkripční faktory paired box genetika   metabolismus   metabolismus   MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH