Phototransduction in Transgenic Mice after Targeted Deletion of the Rod Transducin α-Subunit

Retinal photoreceptors use the heterotrimeric G protein transducin to couple rhodopsin to a biochemical cascade that underlies the electrical photoresponse. Several isoforms of each transducin subunit are present in the retina. Although rods and cones seem to contain distinct transducin subunits, it...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2000-12, Vol.97 (25), p.13913-13918
Main Authors: Calvert, P. D., Krasnoperova, N. V., Lyubarsky, A. L., Isayama, T., Nicoló, M., Kosaras, B., Wong, G., Gannon, K. S., Margolskee, R. F., Sidman, R. L., Pugh, E. N., Makino, C. L., Lem, J.
Format: Article
Language:English
Subjects:
Animals
Antibodies
Base Sequence
Biological Sciences
DNA Primers
Electrodes
Eyes & eyesight
Light
Mice
Mice, Knockout
Mice, Transgenic
Neurology
Neurons
Ophthalmology
Photoreceptors
Phototransduction
Proteins
Retina
Retinal Rod Photoreceptor Cells - metabolism
Rodents
Sequence Deletion
Spectral sensitivity
Transducin - genetics
Vision, Ocular
Wavelengths
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Retinal photoreceptors use the heterotrimeric G protein transducin to couple rhodopsin to a biochemical cascade that underlies the electrical photoresponse. Several isoforms of each transducin subunit are present in the retina. Although rods and cones seem to contain distinct transducin subunits, it is not known whether phototransduction in a given cell type depends strictly on a single form of each subunit. To approach this question, we have deleted the gene for the rod transducin α-subunit in mice. In hemizygous knockout mice, there was a small reduction in retinal transducin α-subunit content but retinal morphology and the physiology of single rods were largely normal. In homozygous knockout mice, a mild retinal degeneration occurred with age. Rod-driven components were absent from the electroretinogram, whereas cone-driven components were retained. Every photoreceptor examined by single-cell recording failed to respond to flashes, with one exception. The solitary responsive cell was insensitive, as expected for a cone, but had a rod-like spectral sensitivity and flash response kinetics that were slow, even for rods. These results indicate that most if not all rods use a single transducin type in phototransduction.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.250478897