HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Chen, J. Articles by McGinnis, J. F. Search for Related Content PubMed PubMed Citation Articles by Chen, J. Articles by McGinnis, J. F.

Light Threshold–Controlled Cone -Transducin Translocation

¹From the Oklahoma Center for Neuroscience, the ²Dean A. McGee Eye Institute, and the ³Departments of Physiology, ⁴Cell Biology, and ⁵Ophthalmology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.

PURPOSE. Light-induced translocation of rod -transducin (rT, GNAT1) has been recognized as one of the mechanisms for light adaptation in rods. However, cone -transducin (cT, GNAT2) has not been shown to have such light-dependent redistribution. To investigate potential reasons for the restriction of cT to the cone outer segment, the authors established a transient transgenic strategy to express cone T within rod photoreceptor cells, and the location of the cone T within rods and cones was examined under different light conditions.

METHODS. Vector DNA that expresses cT and green fluorescent protein (GFP) bicistronically under control of the cytomegalovirus (CMV) promoter was injected subretinally into the eyes of neonatal rats, and this was followed by electroporation. The localization of cT in rods and cones under different light conditions was determined by immunofluorescent techniques.

RESULTS. Injection of the cDNA constructs resulted in the successful transient transfection of retinal cells. When cT was exogenously expressed in rods, its localization paralleled that of endogenous rT under light and dark conditions. Further experiments, with higher intensity light (7000 lux), demonstrated that endogenous cT can also translocate in cone photoreceptor cells to the same extent it does in rods under 600 lux light.

CONCLUSIONS. The authors successfully established an in vivo transient retinal transfection model. The demonstration of cT translocation in rods indicates cT is not inherently prevented from translocating. The novel observation of cT translocation under high-intensity light suggests a light threshold regulates the redistribution of cT possibly as a protective response against very bright light.

This article has been cited by other articles:

				W.-T. Deng, K. Sakurai, J. Liu, A. Dinculescu, J. Li, J. Pang, S.-H. Min, V. A. Chiodo, S. L. Boye, B. Chang, et al. Functional interchangeability of rod and cone transducin {alpha}-subunits PNAS, October 20, 2009; 106(42): 17681 - 17686. [Abstract] [Full Text] [PDF]