title: Spectral Tuning of Phototaxis by a Go-Opsin in the Rhabdomeric Eyes of Platynereis.
abstract: Phototaxis is characteristic of the pelagic larval stage of most bottom-dwelling marine invertebrates. Larval phototaxis is mediated by simple eyes that can express various types of light-sensitive G-protein-coupled receptors known as opsins. Since opsins diversified early during metazoan evolution in the marine environment, understanding underwater light detection could elucidate this diversification. Opsins have been classified into three major families, the r-opsins, the c-opsins, and the Go/RGR opsins, a family uniting Go-opsins, retinochromes, RGR opsins, and neuropsins. The Go-opsins form an ancient and poorly characterized group retained only in marine invertebrate genomes. Here, we characterize a Go-opsin from the marine annelid Platynereis dumerilii. We found Go-opsin1 coexpressed with two r-opsins in depolarizing rhabdomeric photoreceptor cells in the pigmented eyes of Platynereis larvae. We purified recombinant Go-opsin1 and found that it absorbs in the blue-cyan range of the light spectrum. To characterize the function of Go-opsin1, we generated a Go-opsin1 knockout Platynereis line by zinc-finger-nuclease-mediated genome engineering. Go-opsin1 knockout larvae were phototactic but showed reduced efficiency of phototaxis to wavelengths matching the in vitro Go-opsin1 spectrum. Our results highlight spectral tuning of phototaxis as a potential mechanism contributing to opsin diversity.
authors.affiliation: Max Planck Institute for Developmental Biology, Spemannstraße 35, 72076 Tübingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Gühmann
authors.affiliation: Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA 30322, USA.
authors.forename: Huiyong
authors.initials: H
authors.lastname: Jia
authors.affiliation: Max Planck Institute for Developmental Biology, Spemannstraße 35, 72076 Tübingen, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Randel
authors.affiliation: Max Planck Institute for Developmental Biology, Spemannstraße 35, 72076 Tübingen, Germany.
authors.forename: Csaba
authors.initials: C
authors.lastname: Verasztó
authors.affiliation: Max Planck Institute for Developmental Biology, Spemannstraße 35, 72076 Tübingen, Germany.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Bezares-Calderón
authors.affiliation: Department of Biology, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Nico K
authors.initials: NK
authors.lastname: Michiels
authors.affiliation: Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA 30322, USA.
authors.forename: Shozo
authors.initials: S
authors.lastname: Yokoyama
authors.affiliation: Max Planck Institute for Developmental Biology, Spemannstraße 35, 72076 Tübingen, Germany. Electronic address: gaspar.jekely@tuebingen.mpg.de.
authors.forename: Gáspár
authors.initials: G
authors.lastname: Jékely
mesh_terms: D000818:Animals; D008969:Molecular Sequence Data; D055355:Opsins / Q000235:genetics* / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology*; D010802:Phylogeny; D011077:Polychaeta / Q000235:genetics / Q000502:physiology*; D017422:Sequence Analysis, DNA
chemical_list: D055355:Opsins