Lyubarsky, A. L. and Chen, C.-K. and Naarendorp, F. and Zhang, X. and Wensel, T. and Simon, M. I. and Pugh, E. N., Jr. (2001) RGS9-1 is required for normal inactivation of mouse cone phototransduction. Molecular Vision, 7 (11). pp. 71-78. ISSN 1090-0535 http://resolver.caltech.edu/CaltechAUTHORS:LYUmv01
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Purpose: To test the hypothesis that Regulator of G-protein Signaling 9 (RGS9-1) is necessary for the normal inactivation of retinal cones. Methods: Mice having the gene RGS9-1 inactivated in both alleles (RGS9-1 -/-) were tested between the ages 8-10 weeks with electroretinographic (ERG) protocols that isolate cone-driven responses. Immunohistochemistry was performed with a primary antibody against RGS9-1 (anti-RGS9-1c), with the secondary conjugated to fluorescein isothiocyanate, and with rhodamine-conjugated peanut agglutinin. Results: (1) Immunohistochemistry showed RGS9-1 to be strongly expressed in the cones of wildtype (WT is C57BL/6) mice, but absent from the cones of RGS9-1 mice. (2) Cone-driven b-wave responses of dark-adapted RGS9-1 -/- mice had saturating amplitudes and sensitivities in the midwave and UV regions of the spectrum equal to or slightly greater than those of WT (C57BL/6) mice. (3) Cone-driven b-wave and a-wave responses of RGS9-1 -/- mice recovered much more slowly than those of WT after a strong conditioning flash: for a flash estimated to isomerize 1.2% of the M-cone pigment and 0.9% of the UV-cone pigment, recovery of 50% saturating amplitude was approximately 60-fold slower than in WT. Conclusions: (1) The amplitudes and sensitivities of the cone-driven responses indicate that cones and cone-driven neurons in RGS9-1 -/- mice have normal generator currents. (2) The greatly retarded recovery of cone-driven responses of RGS9-1 -/- mice relative to those of WT mice establishes that RGS9-1 is required for normal inactivation of the cone phototransduction cascades of both UV- and M-cones.
|Additional Information:||Received 8 February 2001 | Accepted 19 March 2001 | Published 20 March 2001. Supported by NIH grants to ENP, TGW, and MIS, and by awards from the Research to Prevent Blindness Foundation to ENP and TGW. We thank Ann Milam (Department of Ophthalmology, University of Pennsylvania) and Trevor Lamb (Department of Physiology, University of Cambridge), and the reviewers, for helpful comments.|
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|Deposited On:||13 May 2005|
|Last Modified:||26 Dec 2012 08:39|
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