Purchase this article with an account.
Molly R Proud, Christy Donmoyer; Expression of Opsins in the Retina of the Lrat-/- Mouse, a Model of Vitamin A Deficiency. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):4649.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Vitamin A deficiency (VAD) is the leading cause of preventable childhood blindness. We examined genes that encode for functional proteins of the retina including rhodopsin, blue cone opsin, and melanopsin using a mouse model of VAD. Rhodopsin and blue cone opsin are involved in image-forming processes, while melanopsin is involved in the regulation of circadian rhythm.
Mice aged postnatal (P) days 11, 21, and ~90 (adult) from the C57BL/6J (wild type) and lecithin retinol acyltransferase knockout (Lrat-/-) strains were used. Mice were sacrificed by CO2 exposure, bilaterally enucleated, and retinas were extracted and frozen at -80oC. For each age group and strain, 3 samples were collected consisting of 3-7 mice, totaling 18 samples. Tissues were homogenized and RNA was extracted. cDNA templates were made and qPCR was performed. Each cycle threshold (Ct) value was converted to 2-ΔCt using reference gene 18S rRNA in order to compare by fold difference. Mean and standard errors of the mean were reported. Two-tailed student’s t-tests were used for analysis between each age/strain pair.
For both strains, relative expression of rhodopsin was the highest and melanopsin the lowest. At all ages, relative expressions of rhodopsin and blue cone opsin were higher (2 fold) in the wild type strain than in the Lrat-/- strain, while melanopsin was similar in both strains. Though the results show noticeable trends, none of the observations reached statistical significance (p>0.05).
Genes involved in image-forming processes were expressed less in Lrat-/- mice than in wild type mice at the same age. Melanopsin expression was similar in the strains, suggesting that non-image forming functions in the retina are less affected by VAD than image-forming processes. Perhaps this is due to melanopsin’s evolutionary importance in controlling circadian rhythm.
This PDF is available to Subscribers Only