Real-time monitoring of chloroplast gene expression by a luciferase reporter: Evidence for nuclear regulation of chloroplast circadian period
Real-time monitoring of chloroplast gene expression by a luciferase reporter: Evidence for nuclear regulation of chloroplast circadian period
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DOI：
10.1128/mcb.26.3.863-870.2006
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发表时间：
2006-02-01
影响因子：
5.3
通讯作者：
Ishiura, M
中科院分区：
文献类型：
--
作者：
Matsuo, T;Onai, K;Ishiura, M
叶绿体编码的基因，像核编码的基因，表现出昼夜节律的表达。然而，生物钟如何控制叶绿体基因的表达却知之甚少。为了促进叶绿体昼夜节律基因表达的研究，我们开发了一个密码子优化的萤火虫荧光素酶基因的叶绿体的衣原体reinhardii作为实时生物发光报告，并将其引入到叶绿体基因组。报道菌株的生物发光与引入基因的昼夜表达模式相关性良好，并且满足昼夜节律的所有三个标准。此外，在核基因组中携带长周期基因的趋光节律突变体per突变体中，节律周期延长。这些结果表明，叶绿体基因表达节律是一个真正的昼夜节律，细胞核编码的昼夜节律振荡器决定了叶绿体节律的周期长度。我们的报告菌株可以作为一个强大的工具，不仅为叶绿体基因表达的昼夜节律调控机制的分析，但也为遗传方法的分子振荡器的藻类生物钟。
Chloroplast-encoded genes, like nucleus-encoded genes, exhibit circadian expression. How the circadian clock exerts its control over chloroplast gene expression, however, is poorly understood. To facilitate the study of chloroplast circadian gene expression, we developed a codon-optimized firefly luciferase gene for the chloroplast of Chlamydomonas reinhardiii as a real-time bioluminescence reporter and introduced it into the chloroplast genome. The bioluminescence of the reporter strain correlated well with the circadian expression pattern of the introduced gene and satisfied all three criteria for circadian rhythms. Moreover, the period of the rhythm was lengthened in per mutants, which are phototactic rhythm mutants carrying a long-period gene in their nuclear genome. These results demonstrate that chloroplast gene expression rhythm is a bona fide circadian rhythm and that the nucleus-encoded circadian oscillator determines the period length of the chloroplast rhythm. Our reporter strains can serve as a powerful tool not only for analysis of the circadian regulation mechanisms of chloroplast gene expression but also for a genetic approach to the molecular oscillator of the algal circadian clock.