Regeneration of 11-cis-Retinal in Visual Systems with Monostable and Bistable Visual Pigments

Saari, John C.

doi:10.1007/978-4-431-54880-5_3

Cited by 3 publications

(7 citation statements)

References 126 publications

(159 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Vertebrates have light and dark visual cycles, and different visual cycles for their rod and cone PRCs [ 156 , 157 , 158 ]. In the dark visual cycle of the rod PRCs, all- trans retinal is reduced to all- trans retinol by retinol dehydrogenases (RDHs), specifically RDH8 (and potentially additional RDHs) [ 159 ].…”

Section: Visual Cyclementioning

confidence: 99%

Deep Diversity: Extensive Variation in the Components of Complex Visual Systems across Animals

Vöcking

Macias-Muñoz

Jaeger

et al. 2022

Cells

View full text Add to dashboard Cite

Understanding the molecular underpinnings of the evolution of complex (multi-part) systems is a fundamental topic in biology. One unanswered question is to what the extent do similar or different genes and regulatory interactions underlie similar complex systems across species? Animal eyes and phototransduction (light detection) are outstanding systems to investigate this question because some of the genetics underlying these traits are well characterized in model organisms. However, comparative studies using non-model organisms are also necessary to understand the diversity and evolution of these traits. Here, we compare the characteristics of photoreceptor cells, opsins, and phototransduction cascades in diverse taxa, with a particular focus on cnidarians. In contrast to the common theme of deep homology, whereby similar traits develop mainly using homologous genes, comparisons of visual systems, especially in non-model organisms, are beginning to highlight a “deep diversity” of underlying components, illustrating how variation can underlie similar complex systems across taxa. Although using candidate genes from model organisms across diversity was a good starting point to understand the evolution of complex systems, unbiased genome-wide comparisons and subsequent functional validation will be necessary to uncover unique genes that comprise the complex systems of non-model groups to better understand biodiversity and its evolution.

show abstract

Section: Visual Cyclementioning

confidence: 99%

Deep Diversity: Extensive Variation in the Components of Complex Visual Systems across Animals

Vöcking

Macias-Muñoz

Jaeger

et al. 2022

Cells

View full text Add to dashboard Cite

show abstract

“…Yet, both visual systems have additional mechanisms to recycle retinal back to the 11-cis conformation. Vertebrates have light and dark visual cycles, and different visual cycles for their rod and cone PRCs (Wang and Kefalov 2011;Saari 2014;Choi et al 2021). In the dark visual cycle of the rod PRCs, all-trans-retinal is reduced to all-trans-retinol by retinol dehydrogenases (RDHs), specifically RDH8 (and potentially additional RDHs) (Saari 2012).…”

Section: Visual Cyclementioning

confidence: 99%

“…Vertebrates have light and dark visual cycles, and different visual cycles for their rod and cone PRCs (Wang and Kefalov 2011;Saari 2014;Choi et al 2021). In the dark visual cycle of the rod PRCs, all-trans-retinal is reduced to all-trans-retinol by retinol dehydrogenases (RDHs), specifically RDH8 (and potentially additional RDHs) (Saari 2012). Alltrans-retinol is transported through the interphotoreceptor matrix by chaperoning interphotoreceptor retinoid-binding protein (IRBP or RBP3) into the adjacent cells of the retinal pigment epithelium (RPE) where it is bound by the cellular retinol binding protein, CRBP1.…”

Section: Visual Cyclementioning

confidence: 99%

“…Consecutively, the isomerohydrolase RPE65 hydrolyzes and isomerizes the all-trans-retinyl ester to the respective fatty acid and 11-cis-retinol, which is then bound by the retinaldehyde binding protein RLBP1 (CRALBP). Subsequently, RDH5 catalyzes final oxidation to 11cis-retinal before retinal is transported back to the rod PRC by IRBP to complete the cycle and regenerate rhodopsin (Kuksa et al 2003;Radu et al 2008;Saari 2012Saari , 2014Tang et al 2013;Choi et al 2021).…”

Section: Visual Cyclementioning

confidence: 99%

“…Hara and Hara 1991;R. Hara, Hara, and Tokunaga 1981;Ozaki et al 1983;Saari 2014). In squid, retinochrome is expressed in the inner segments of the PRCs and the basal regions of the outer segments, which is a contrast to r-opsins, which is only found in the rhabdomeric microvilli (T. Hara and Hara 1976;Ozaki et al 1983;T.…”

Section: Invertebrate Visual Cyclementioning

confidence: 99%

See 2 more Smart Citations

Deep Diversity: Extensive Variation in the Components of Complex Visual Systems across Animals

Vöcking¹,

Macias-Muñoz²,

Jaeger³

et al. 2022

Preprint

View full text Add to dashboard Cite

Understanding the molecular underpinnings of the evolution of complex (multi-part) systems is a fundamental topic in biology. One unanswered question is the extent to which similar or different genes and regulatory interactions underlie similar complex systems across species. Animal eyes and phototransduction (light detection) are outstanding systems to investigate this question because some of the genetics underlying these traits are well-characterized in model organisms. However, comparative studies using non-model organisms are also necessary to understand the diversity and evolution of these traits. Here, we compare the characteristics of photoreceptor cells, opsins, and phototransduction cascades in diverse taxa, with particular focus on cnidarians. In contrast to the common theme of deep homology, whereby similar traits develop mainly using homologous genes, comparisons of visual systems - especially in non-model organisms - are beginning to highlight a “deep diversity” of underlying components, illustrating how variation can underlie similar complex systems across taxa. Although using candidate genes from model organisms across diversity was a good starting point to understand the evolution of complex systems, unbiased genome-wide comparisons and subsequent functional validation will be necessary to uncover unique genes that comprise complex systems of non-model groups to better understand biodiversity and its evolution.

show abstract

The rhodopsin-retinochrome system for retinal re-isomerization predates the origin of cephalopod eyes

2021

View full text Add to dashboard Cite

Background The process of photoreception in most animals depends on the light induced isomerization of the chromophore retinal, bound to rhodopsin. To re-use retinal, the all-trans-retinal form needs to be re-isomerized to 11-cis-retinal, which can be achieved in different ways. In vertebrates, this mostly includes a stepwise enzymatic process called the visual cycle. The best studied re-isomerization system in protostomes is the rhodopsin-retinochrome system of cephalopods, which consists of rhodopsin, the photoisomerase retinochrome and the protein RALBP functioning as shuttle for retinal. In this study we investigate the expression of the rhodopsin-retinochrome system and functional components of the vertebrate visual cycle in a polyplacophoran mollusk, Leptochiton asellus, and examine the phylogenetic distribution of the individual components in other protostome animals. Results Tree-based orthology assignments revealed that orthologs of the cephalopod retinochrome and RALBP are present in mollusks outside of cephalopods. By mining our dataset for vertebrate visual cycle components, we also found orthologs of the retinoid binding protein RLBP1, in polyplacophoran mollusks, cephalopods and a phoronid. In situ hybridization and antibody staining revealed that L. asellus retinochrome is co-expressed in the larval chiton photoreceptor cells (PRCs) with the visual rhodopsin, RALBP and RLBP1. In addition, multiple retinal dehydrogenases are expressed in the PRCs, which might also contribute to the rhodopsin-retinochrome system. Conclusions We conclude that the rhodopsin-retinochrome system is a common feature of mollusk PRCs and predates the origin of cephalopod eyes. Our results show that this system has to be extended by adding further components, which surprisingly, are shared with vertebrates.

show abstract

Regeneration of 11-cis-Retinal in Visual Systems with Monostable and Bistable Visual Pigments

Cited by 3 publications

References 126 publications

Deep Diversity: Extensive Variation in the Components of Complex Visual Systems across Animals

Deep Diversity: Extensive Variation in the Components of Complex Visual Systems across Animals

Deep Diversity: Extensive Variation in the Components of Complex Visual Systems across Animals

The rhodopsin-retinochrome system for retinal re-isomerization predates the origin of cephalopod eyes

Contact Info

Product

Resources

About