Cell autonomous and cell-type specific circadian rhythms in Arabidopsis.
Cell autonomous and cell-type specific circadian rhythms in Arabidopsis.
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DOI：
10.1111/j.1365-313x.2011.04707.x
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发表时间：
2011-11
期刊：
影响因子：
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通讯作者：
Esther Yakir;M. Hassidim;N. Melamed‐Book;Dror Hilman;Ido Kron;R. Green
中科院分区：
文献类型：
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作者：
Esther Yakir;M. Hassidim;N. Melamed‐Book;Dror Hilman;Ido Kron;R. Green
植物的昼夜节律系统以24 h左右为周期调节着广泛的节律性生理和细胞输出过程。这些节律是由振荡器机制产生的，在拟南芥中，该振荡器机制由几个组件的互锁反馈环组成，包括昼夜节律相关1（CCA1）、晚伸长下胚轴（LHY）、CAB表达时间1（TOC1）和CCA1漫游扩展（CHE）。近年来，研究人员已经在整个植物和几种组织类型的分辨率上获得了时钟机制的详细图像，但对单个细胞水平上时钟机制的特异性知之甚少。在本文中，我们已经解决了昼夜节律系统中细胞类型特异性差异的问题。使用转基因拟南芥植物与荧光标记的CCA1测量在完整的活植物中的单个叶细胞的节律性，我们发现，气孔保卫细胞有不同的时期从周围的表皮和叶肉叶细胞。通过比较保卫细胞与整株植物的转录水平，我们确定了一些振荡基因表达的差异，这些差异可能是细胞特异性时钟特性差异的基础。此外，我们还证明了叶中单个细胞的振荡器是稳健的，但在恒定条件下会变得部分不稳定。总之，我们的研究结果表明，在单个细胞的水平上，有不同的典型振荡器机制，已被描述为植物。
The circadian system of plants regulates a wide range of rhythmic physiological and cellular output processes with a period of about 24 h. The rhythms are generated by an oscillator mechanism that, in Arabidopsis, consists of interlocking feedback loops of several components including CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), LATE ELONGATED HYPOCOTYL (LHY), TIMING OF CAB EXPRESSION 1 (TOC1) and CCA1 HIKING EXPEDITION (CHE). Over recent years, researchers have gained a detailed picture of the clock mechanism at the resolution of the whole plant and several tissue types, but little information is known about the specificities of the clock mechanism at the level of individual cells. In this paper we have addressed the question of cell-type-specific differences in circadian systems. Using transgenic Arabidopsis plants with fluorescence-tagged CCA1 to measure rhythmicity in individual leaf cells in intact living plants, we showed that stomatal guard cells have a different period from surrounding epidermal and mesophyll leaf cells. By comparing transcript levels in guard cells with whole plants, we identified differences in the expression of some oscillator genes that may underlie cell-specific differences in clock properties. In addition, we demonstrated that the oscillators of individual cells in the leaf are robust, but become partially desynchronized in constant conditions. Taken together our results suggest that, at the level of individual cells, there are differences in the canonical oscillator mechanism that has been described for plants.