Prosaposin Gene Expression in Normal and Dystrophic RCS Rat Retina

RESULTS. The cDNA encoding prosaposin was isolated. This is the first time this gene has been shown to be expressed in the retina. Prosaposin mRNA was detected in the rat RPE cell monolayer and in ganglion cells 14, 21, and 45 days after birth. The amount of prosaposin mRNA increased between days 14 and 45 after birth in normal retinas (rdy), but not in the pathologic retinas (rdy) of RCS rats. CONCLUSIONS. Several techniques were used to determine the localization of prosaposin in rat retinas. The increase in the amount of prosaposin mRNA in normal retinas coincided with the maturation of photoreceptor cells and the beginning of the phagocytosis process. In addition, the RCS rdy RPE cells, characterized by the abrogation of the ingestion phase of the photoreceptor outer segments, are deficient in prosaposin expression. (Invest Ophthalmol Vis Sci. 2004;45:1297‐1305)