OPSIN DISTRIBUTION AND SYNTHESIS IN DEGENERATING PHOTORECEPTORS OF RD MUTANT MICE
OPSIN DISTRIBUTION AND SYNTHESIS IN DEGENERATING PHOTORECEPTORS OF RD MUTANT MICE
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DOI：
10.1016/0014-4835(89)90050-x
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发表时间：
1989-09-01
影响因子：
3.4
通讯作者：
PAPERMASTER, DS
中科院分区：
文献类型：
--
作者：
NIR, I;AGARWAL, N;PAPERMASTER, DS
研究了携带rd（视网膜变性）突变的小鼠视网膜中视蛋白的分布和光感受器合成视蛋白的能力，并与对照正常小鼠进行了比较。通过包埋前和包埋后免疫细胞化学和电子显微镜对视蛋白进行定位。用抗视锥抗体和标记视锥基质鞘的花生凝集素鉴定视锥。通过将[35S]甲硫氨酸掺入通过免疫印迹检测的视蛋白中来测量视蛋白合成。免疫细胞化学结果显示，视杆外节的变性伴随着视蛋白在胞膜、胞核和突触终末的聚集。视杆细胞比视锥细胞退化快。到出生后第19天（P19），87%的剩余内节是锥形的。rd小鼠中的视蛋白合成在P15后不能再测量。然而，视蛋白分子可以通过免疫细胞化学和免疫印迹检测到P30。在P20和P30之间，所有可检测到的视蛋白都定位于包裹细胞核和突触终末的质膜中。P30后存活的未标记细胞核可能是视锥细胞。视蛋白在视杆细胞内节质膜中被检测到，可能是通过反向扩散从退化的外节获得的，并且代表在较早时间合成的分子。或者，视蛋白积累可能是低水平的视蛋白合成的结果，通过[35S]甲硫氨酸掺入检测不到，其在不存在外节的情况下继续。
The distribution of opsin and the capacity of photoreceptors to synthesize opsin was studied in retinas of mice bearing the rd (retinal degeneration) mutation and compared to control normal mice. Opsin was localized by means of pre-embedding and post-embedding immunocytochemistry and electron microscopy. Cones were identified with anti-cone antibodies and peanut agglutinin lectin which labels cone matrix sheaths. Opsin synthesis was measured by incorporation of [35S]methionine into opsin which was detected by immunoblots. Immunocytochemistry revealed that degeneration of rod outer segments was accompanied by accumulation of opsin in the plasma membrane enveloping the inner segment, nuclei and synaptic terminals. Rod photoreceptors degenerated faster than cones. By post-natal day 19 (P19), 87% of the remaining inner segments were cone. Opsin synthesis in rd mice could no longer be measured after P15. However, opsin molecules could be detected both by immunocytochemistry and immunoblotting up to P30. Between P20 and P30 all detectable opsin was localized in the plasma membrane which envelopes nuclei and synaptic terminals. Unlabeled surviving nuclei after P30 are probably cones. The opsin which is detected in rod inner segment plasma membranes might be derived, by back diffusion, from degenerating outer segments and represent molecules synthesized at an earlier time. Alternatively opsin accumulation might be a result of low levels of opsin synthesis, undetectable by [35S]methionine incorporation, which continues in the absence of outer segments.