Autoregulation of rhodopsin synthesis in Chlamydomonas reinhardtii.
Autoregulation of rhodopsin synthesis in Chlamydomonas reinhardtii.
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莱茵衣藻视紫红质合成的自动调节。
DOI：
10.1073/pnas.85.17.6379
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发表时间：
1988
影响因子：
11.1
通讯作者：
Zarrilli,G
中科院分区：
文献类型：
--
作者：
Foster,KW;Saranak,J;Zarrilli,G
一个敏感的检测诱导类胡萝卜素和视紫红质的合成，趋光反应的基础上，已开发的单细胞衣藻莱茵衣藻突变体。在黑暗中，突变体不能合成胡萝卜素和视黄醇，但它含有脱辅基蛋白视蛋白。当光处理诱导视网膜合成时，视网膜与视蛋白结合形成视紫红质，细胞游离光源。由于触发趋光反应所需的光量与视紫红质的浓度成反比，因此产生该反应所需的光量的减少可以用作诱导后细胞中合成的视网膜的量的量度。结果表明：（1）视网膜的光诱导作用与光暴露量和暴露过程中视紫红质浓度呈线性关系，（2）视网膜光诱导作用的光谱与视紫红质为受体的趋光作用的光谱一致;和（iii）在光暴露之前与全反式-7，8-二氢视黄醛一起温育，使光诱导的作用光谱峰移动0.41eV（~ 71 nm）。我们的结论是诱导视网膜合成的色素是视紫红质。诱导视网膜合成所需的时间滞后和转录或翻译抑制剂的初步实验表明，基因表达的改变可能参与诱导过程。它的控制可能类似于激素、神经递质或生长因子的膜受体调节基因表达的其他过程。
A sensitive assay for the induction of carotenoid and rhodopsin synthesis, based on the phototactic response, has been developed in a mutant of the unicellular alga Chlamydomonas reinhardtii. In the dark, the mutant fails to synthesize carotene and retinal, but it contains the apoprotein opsin. When retinal synthesis is induced by light treatment, the retinal combines with opsin to form rhodopsin, and the cells swim away from a source of light. Since the amount of light required to trigger a phototactic response is inversely proportional to the concentration of rhodopsin, the decrease in amount of light necessary to generate that response can serve as a measure of the amount of retinal synthesized in cells after induction. Using this assay, we found that (i) light induction of retinal depends linearly on light exposure and rhodopsin concentration during the exposure; (ii) the action spectrum of light induction is identical with that for phototaxis for which the receptor pigment is rhodopsin; and (iii) incubation with all-trans-7,8-dihydroretinal before light exposure shifts the action-spectrum peak for light induction 0.41 eV (-71 nm). We conclude that the photopigment for induction of retinal synthesis is a rhodopsin. The time lag required for induction of retinal synthesis and preliminary experiments with transcription or translation inhibitors suggest that alterations in gene expression could be involved in the induction process. Its control could be similar to other processes in which membrane receptors for hormones, neurotransmitters, or growth factors regulate gene expression.