Expression of soluble phototransduction-associated proteins in ground squirrel retina.
OBJECTIVE
This study describes the expression and distribution of arrestin, phosducin, and recoverin in the cone-dominant retina of the ground squirrel Spermophilus tridecemlineatus.


METHODS
mRNA expression was studied by blot hybridization of ground squirrel retinal RNA, with human and murine RNA as controls. The distribution of the gene products in the ground squirrel retina was investigated by immunocytochemistry using radial and consecutive tangential sections.


RESULTS
Northern blot hybridization showed messages for arrestin (1.9 kb), phosducin (1.4 kb), and recoverin (1.2 kb) in ground squirrel retinal RNA. Both controls showed transcripts of the same or similar sizes. Rod-like cells and blue cones were stained by antibodies against arrestin and phosducin. The arrestin antiserum stained the whole cell bodies, most intensely in the myoid region, whereas phosducin immunoreactivity was confined to the outer and inner segments, which were stained with approximately equal intensity. The strongest immunoreaction was found in the photoreceptor plasma membrane. Recoverin antibodies recognized the entire soma of all photoreceptor cells. The myoid region and the synaptic pedicles were most heavily stained. No light-dependent migration was observed with either antiserum in any photoreceptor type.


CONCLUSIONS
The presence of arrestin immunoreactivity in rod-like cells and blue cones is consistent with previous reports on other mammals. However, it has not been reported previously that phosducin immunoreactivity is distributed in the same way. The colocalization of arrestin and phosducin in rod-like cells and blue cones is yet another trait distinguishing blue cones from red and green cones.
von Schantz
M
M
Department of Zoology, University of Göteborg, Sweden.
Szél
A
A
van Veen
T
T
Farber
D B
DB
D000818:Animals; D000941:Antigens / Q000235:genetics / Q000378:metabolism; D019393:Arrestin; D015152:Blotting, Northern; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D020555:GTP-Binding Protein Regulators; D051597:Hippocalcin; D006801:Humans; D007124:Immunoenzyme Techniques; D008027:Light; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D009693:Nucleic Acid Hybridization; D010726:Phosphodiesterase Inhibitors / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010786:Photoreceptor Cells / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051603:Recoverin; D012589:Sciuridae; D015398:Signal Transduction / Q000502:physiology*; D012995:Solubility
D000941:Antigens; D019393:Arrestin; D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D010726:Phosphodiesterase Inhibitors; D010750:Phosphoproteins; C496731:RCVRN protein, human; D012333:RNA, Messenger; C065631:phosducin; D051603:Recoverin; D051597:Hippocalcin; D011494:Protein Kinases