Smith S B, Lee L, Nickerson J, Si J S, Chader G J, Wiggert B
Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892.
Exp Eye Res. 1992 Jun;54(6):957-63. doi: 10.1016/0014-4835(92)90160-t.
The synthesis and secretion of interphotoreceptor retinoid-binding protein (IRBP) was quantitatively assessed in retinas of normal and rd mutant mice using short-term organ culture with [35S]methionine. Retinas were studied at ages P9-P12, time points prior to and immediately after the onset of the degeneration of the rd retina. Soluble proteins of the retinal pellet and the incubation medium were subjected to SDS-polyacrylamide gel electrophoresis. Analysis of labeled protein bands utilized a radioactivity scanning system to quantify [35S]methionine incorporation into newly synthesized IRBP. The synthesis and secretion into the incubation medium of IRBP by rd mouse retinas was comparable to normal retinas at P9-P10 but decreased by more than 50% by P12. IRBP mRNA levels were evaluated in retinas of normal and rd mice ages P7-P14. Although IRBP mRNA expression increased in the rd mouse through P10, it decreased markedly thereafter. Previously reported immunocytochemical studies suggested that IRBP was not secreted in the rd mouse retina. The results of this study indicate, however, that rd mouse retinas, when removed from the eye, have the capacity to synthesize and secrete IRBP.
利用含[35S]甲硫氨酸的短期器官培养法，对正常小鼠和rd突变小鼠视网膜中感光细胞间类视黄醇结合蛋白（IRBP）的合成与分泌进行了定量评估。研究的视网膜取材于P9 - P12年龄段，这是rd视网膜开始退化之前及退化刚开始后的时间点。对视网膜沉淀和孵育培养基中的可溶性蛋白质进行SDS - 聚丙烯酰胺凝胶电泳。对标记蛋白条带的分析利用放射性扫描系统来量化[35S]甲硫氨酸掺入新合成的IRBP中的情况。rd小鼠视网膜IRBP向孵育培养基中的合成与分泌在P9 - P10时与正常视网膜相当，但到P12时减少了50%以上。评估了P7 - P14年龄段正常小鼠和rd小鼠视网膜中IRBP mRNA的水平。虽然rd小鼠中IRBP mRNA表达在P10之前增加，但此后显著下降。先前报道的免疫细胞化学研究表明IRBP在rd小鼠视网膜中不分泌。然而，本研究结果表明，rd小鼠视网膜从眼中取出后具有合成和分泌IRBP的能力。
