A mouse-like retinal cone phenotype in the Syrian hamster: S opsin coexpressed with M opsin in a common cone photoreceptor.
Previous immunocytochemical, physiological, and molecular studies have reported that the Syrian hamster lacks a shortwave-sensitive (S) cone photopigment but retains circadian responses to ultraviolet (UV) light. Using opsin antibodies and a sensitive detection protocol, we here show that S opsin immunoreactivity colocalizes with M opsin immunoreactivity in a common type of cone photoreceptor. S opsin signal within individual cone outer segments is low and continuously decreases from the ventral to dorsal retina. Only double-labeled cones were found. During development, S opsin expression precedes that of M opsin, but there is no indication of transdifferentiation. Our results imply that in the Syrian hamster low levels of S opsin colocalize with M opsin in a common cone phenotype. We suggest that, similar to other murid rodents, the S pigment absorbs maximally in the UV range, and thus may contribute to mediating the circadian response of the Syrian hamster to UV light.
Glösmann
Martin
M
Institute of Physiology, Medical School, University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria. martin.gloesmann@univie.ac.at
Ahnelt
Peter K
PK
D000818:Animals; D000831:Animals, Newborn; D002452:Cell Count; D002940:Circadian Rhythm / Q000502:physiology*; D006224:Cricetinae; D015870:Gene Expression / Q000502:physiology; D007150:Immunohistochemistry; D055537:Light Signal Transduction / Q000502:physiology*; D008647:Mesocricetus; D051379:Mice; D010641:Phenotype; D020033:Protein Isoforms / Q000378:metabolism; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000166:cytology / Q000378:metabolism; D017299:Rod Opsins / Q000378:metabolism*; D014466:Ultraviolet Rays
D020033:Protein Isoforms; D017299:Rod Opsins