Jared D Chrispell1, Enheng Dong1, Shoji Osawa1, Jiandong Liu2, D Joshua Cameron3, Ellen R Weiss1,4. 1. Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States. 2. Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States. 3. College of Optometry, Western University of Health Sciences, Pomona, California, United States. 4. Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States.
Abstract
Purpose: To define the functional roles of Grk1 and Grk7 in zebrafish cones in vivo. Methods: Genome editing was used to generate grk7a and grk1b knockout zebrafish. Electroretinogram (ERG) analyses of the isolated cone mass receptor potential and the b-wave were performed in dark-adapted zebrafish using a paired flash paradigm to determine recovery of cone photoreceptors and the inner retina after an initial flash. In addition, psychophysical visual response was measured using the optokinetic response (OKR). Results: ERG analysis demonstrated that deletion of either Grk1b or Grk7a in zebrafish larvae resulted in modestly lower rates of recovery of the isolated cone mass receptor potential from an initial flash compared to wildtype larvae. On the other hand, grk1b-/- and grk7a-/- larvae exhibited a b-wave recovery that was similar to wildtype larvae. We evaluated the OKR and found that deletion of either Grk1b or Grk7a leads to a small decrease in temporal contrast sensitivity and alterations in visual acuity. Conclusions: For the first time, we demonstrate that Grk1b and Grk7a both contribute to visual function in larval zebrafish cones. Since the difference between wildtype and each knockout fish is modest, it appears that either GRK is sufficient for adequate cone visual function.
Purpose: To define the functional roles of Grk1 and Grk7 in zebrafish cones in vivo. Methods: Genome editing was used to generate grk7a and grk1b knockout zebrafish. Electroretinogram (ERG) analyses of the isolated cone mass receptor potential and the b-wave were performed in dark-adapted zebrafish using a paired flash paradigm to determine recovery of cone photoreceptors and the inner retina after an initial flash. In addition, psychophysical visual response was measured using the optokinetic response (OKR). Results: ERG analysis demonstrated that deletion of either Grk1b or Grk7a in zebrafishlarvae resulted in modestly lower rates of recovery of the isolated cone mass receptor potential from an initial flash compared to wildtype larvae. On the other hand, grk1b-/- and grk7a-/- larvae exhibited a b-wave recovery that was similar to wildtype larvae. We evaluated the OKR and found that deletion of either Grk1b or Grk7a leads to a small decrease in temporal contrast sensitivity and alterations in visual acuity. Conclusions: For the first time, we demonstrate that Grk1b and Grk7a both contribute to visual function in larval zebrafish cones. Since the difference between wildtype and each knockout fish is modest, it appears that either GRK is sufficient for adequate cone visual function.
Authors: E R Weiss; D Raman; S Shirakawa; M H Ducceschi; P T Bertram; F Wong; T W Kraft; S Osawa Journal: Mol Vis Date: 1998-12-08 Impact factor: 2.367