Co-expression of xenopsin and rhabdomeric opsin in photoreceptors bearing microvilli and cilia
- University of Bergen, Norway
Abstract
Ciliary and rhabdomeric opsins are employed by cells differing fundamentally in structure and molecular physiology, such as ciliary vertebrate rods and cones and protostome microvillar eye photoreceptors. We report unprecedented cellular co-expression of rhabdomeric opsin and a visual pigment of the recently described xenopsins in larval eyes of a mollusk. The photoreceptors bear both microvilli and cilia and express orthologs to transporters for microvillar and ciliary opsin trafficking. Highly conserved but distinct gene structures suggest that xenopsins and ciliary opsins are of independent origin, irrespective of their mutually exclusive distribution in animals.Furthermore, we propose that frequent opsin gene loss had big influence on evolution, organization and function of brain and eye photoreceptor cells in bilaterian animals. Presence of xenopsin in eyes of even different design might be due to common origin and initial employment in a highly plastic photoreceptor cell type of mixed microvillar/ciliary organization.
Data availability
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Genome of Macrostomum lignanoPublicly available at http://www.macgenome.org.
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Schmidtea mediterranea Genome DatabasePublicly available at http://smedgd.neuro.utah.edu.
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Kumamushi Genome ProjectPublicly available at http://kumamushi.org/database.html.
Article and author information
Author details
Funding
Universitetet i Bergen
- Harald Hausen
Norges Forskningsråd
- Harald Hausen
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Vöcking et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Co-expression of xenopsin and rhabdomeric opsin in photoreceptors bearing microvilli and cilia
eLife 6:e23435.
https://doi.org/10.7554/eLife.23435
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