Transcription of CABII is regulated by the biological clock in Chlamydomonas reinhardtii.
Transcription of CABII is regulated by the biological clock in Chlamydomonas reinhardtii.
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CABII 的转录受莱茵衣藻生物钟的调节。
DOI：
10.1007/bf00040834
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发表时间：
1996
影响因子：
5.1
通讯作者：
Johnson,CH
中科院分区：
文献类型：
--
作者：
Jacobshagen,S;Kindle,KL;Johnson,CH
已知编码光系统II叶绿素b结合蛋白（CABIIorlhcb）的小基因家族在莱茵衣藻中表现出mRNA丰度的昼夜节律。在这项研究中，我们研究了转录在这种现象中的作用。我们使用编码硝酸还原酶（NITI）和芳基硫酸酯酶（ARS 2）的衣原体基因作为转录因子，这些基因与CABII基因（称为CABII-1）的上游序列转录融合。我们发现，这两个报告显示出相同的昼夜节律的mRNA丰度的相位，周期和幅度一样，内源性CABII-1基因。我们还评估了芳基硫酸酯酶酶活性作为报告者的功效，发现其半衰期太长，无法使其成为昼夜节律或昼夜循环期间节律性转录的有用报告者。通过活体标记实验检测了CABII-1基因mRNA的合成量，证实了转录速率的昼夜节律，同时也揭示了整个CABII基因家族mRNA合成的昼夜节律。转录报告基因检测和体内标记实验的结果有力地支持了生物钟调控CABII-1基因转录活性的结论，而且转录水平的调控是生物钟调控该基因的主要方式。
The small gene family encoding the chlorophylla/b-binding proteins of photosystem II (CABIIorlhcb) is known to exhibit circadian rhythms of mRNA abundance inChlamydomonas reinhardtii. In this study we investigated the role of transcription in the phenomenon. We used as reportersChlamydomonasgenes that encode nitrate reductase (NITI) and arylsulfatase (ARS2) transcriptionally fused to sequences upstream of one of theCABIIgenes (calledCABII-1). We found that both reporters exhibited the same circadian rhythm of mRNA abundance in phase, period, and amplitude as does the endogenousCABII-1gene. We also evaluated the efficacy of arylsulfatase enzymatic activity as a reporter and found that its half-life is too long to make it a useful reporter of rhythmic transcription during a circadian or diurnal cycle. The amount of mRNA synthesis from theCABII-1gene was examined byin vivolabeling experiments and a circadian rhythm in transcription rate was demonstrated.In vivolabeling also revealed a circadian rhythm of mRNA synthesis for theCABIIgene family as a whole. The results from the transcriptional reporter assays together with thein vivolabeling experiments strongly support the conclusion that the biological clock regulates the transcriptional activity of theCABII-1gene, and moreover that regulation at the transcriptional level is the predominant mode by which the clock regulates this gene.