Retinal dysfunction in basigin deficiency.
OBJECTIVE
To examine the retina of basigin (Bsg) knockout mice by electrophysiological and histologic methods and thereby to determine the possible function of Bsg in phototransduction and retinal development.


METHODS
Scotopic and photopic electroretinograms (ERGs) were recorded from 11 wild-type, 12 heterozygous, and 8 homozygous Bsg gene knockout mice of different ages. The retinas were also examined by histologic and immunolabeling methods.


RESULTS
Bsg knockout mice of 5 to 41 weeks of age showed a decrease in the amplitude of all components of both the photopic and scotopic ERGs. In contrast, the fundus and the fluorescein fundus angiography and morphology of the retina at the light microscopic level appeared to be normal until 8 weeks of age in Bsg knockout mice. Thereafter, the length of outer segment and outer nuclear layers decreased with increasing age. Immunohistochemical analysis localized Bsg protein in a variety of cells in the retina, especially in the pigment epithelium, the upper outer plexiform layer and the inner segments of photoreceptor cells.


CONCLUSIONS
The results demonstrated that both rod and cone function were severely affected from an early age by the targeted disruption of the Bsg gene. In spite of abnormal ERGs, the photoreceptor cells maintained normal morphology up to 8 weeks. Thereafter, the photoreceptor cells degenerated gradually and were almost ablated by 41 weeks.
Hori
K
K
Department of Ophthalmology, Nagoya University School of Medicine, Tsuruma-cho, Showa-ku, Japan.
Katayama
N
N
Kachi
S
S
Kondo
M
M
Kadomatsu
K
K
Usukura
J
J
Muramatsu
T
T
Mori
S
S
Miyake
Y
Y
D000818:Animals; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface / Q000502:physiology*; D030161:Avian Proteins; D051926:Basigin; D001798:Blood Proteins; D004596:Electroretinography; D005451:Fluorescein Angiography; D019084:Fluorescent Antibody Technique, Indirect; D005654:Fundus Oculi; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D020419:Photoreceptor Cells, Vertebrate / Q000473:pathology / Q000502:physiology*; D012162:Retinal Degeneration / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D014785:Vision, Ocular / Q000502:physiology
D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D030161:Avian Proteins; D001798:Blood Proteins; C102624:Bsg protein, Gallus gallus; C497887:Bsg protein, mouse; C079432:Bsg protein, rat; D008562:Membrane Glycoproteins; D051926:Basigin