title: Recoverin depletion accelerates cone photoresponse recovery.
abstract: The neuronal Ca(2+)-binding protein Recoverin has been shown to regulate phototransduction termination in mammalian rods. Here we identify four recoverin genes in the zebrafish genome, rcv1a, rcv1b, rcv2a and rcv2b, and investigate their role in modulating the cone phototransduction cascade. While Recoverin-1b is only found in the adult retina, the other Recoverins are expressed throughout development in all four cone types, except Recoverin-1a, which is expressed only in rods and UV cones. Applying a double flash electroretinogram (ERG) paradigm, downregulation of Recoverin-2a or 2b accelerates cone photoresponse recovery, albeit at different light intensities. Exclusive recording from UV cones via spectral ERG reveals that knockdown of Recoverin-1a alone has no effect, but Recoverin-1a/2a double-knockdowns showed an even shorter recovery time than Recoverin-2a-deficient larvae. We also showed that UV cone photoresponse kinetics depend on Recoverin-2a function via cone-specific kinase Grk7a. This is the first in vivo study demonstrating that cone opsin deactivation kinetics determine overall photoresponse shut off kinetics.
authors.affiliation: Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Zang
authors.affiliation: Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keim
authors.affiliation: Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
authors.forename: Edda
authors.initials: E
authors.lastname: Kastenhuber
authors.affiliation: Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Gesemann
authors.affiliation: Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland stephan.neuhauss@imls.uzh.ch.
authors.forename: Stephan C F
authors.initials: SC
authors.lastname: Neuhauss
mesh_terms: D000818:Animals; D054768:G-Protein-Coupled Receptor Kinases / Q000378:metabolism; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D051603:Recoverin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology* / Q000528:radiation effects; D014466:Ultraviolet Rays; D015027:Zebrafish; D029961:Zebrafish Proteins
chemical_list: D029961:Zebrafish Proteins; D051603:Recoverin; C504360:grk7b protein, zebrafish; D054768:G-Protein-Coupled Receptor Kinases
keywords: cone photoreceptor; electroretinogram; phototransduction termination; zebrafish