Continuous light exposure causes cumulative stress that affects the localization oscillation dynamics of the transcription factor Msn2p
Continuous light exposure causes cumulative stress that affects the localization oscillation dynamics of the transcription factor Msn2p
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DOI：
10.1016/j.bbamcr.2010.12.004
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发表时间：
2011-02-01
影响因子：
5.1
通讯作者：
Kall, Mikael
中科院分区：
文献类型：
--
作者：
Bodvard, Kristofer;Wrangborg, David;Kall, Mikael
在体内光学显微镜研究中，光暴露是一个潜在的强大应力因素。在酵母中，通用转录因子Msn 2 p响应于光照从细胞质易位到细胞核。然而，以前的延时荧光显微镜研究Msn 2 p利用了各种离散的曝光设置，这使得它很难关联的应力水平和照明参数。我们在这里调查如何连续照射蓝光，对应于GFP的激发波长，影响Msn 2 p-GFP在芽殖酵母中的定位模式。利用小波分解和变点分析相结合的方法对局部化模式进行了分析。发现单个细胞的Msn 2 p核质定位轨迹表现出多达三种不同且连续的状态：i）Msn 2 p定位于细胞质; ii）Msn 2 p在细胞质和细胞核之间快速穿梭; iii）Msn 2 p定位于细胞核。许多细胞在高光强下连续通过所有状态，而在较低光强下大多数细胞仅达到状态i）或ii）。这种行为强烈表明，持续的光照逐渐增加的应力水平随着时间的推移，大概是通过不断积累的有毒的光产物，从而迫使细胞通过一个对应于核质振荡的振荡区。我们还表明，定位模式是依赖于蛋白激酶A（PKA）的活性，即酵母细胞与不断低PKA活性表现出更强的应激反应。特别是，核质振荡频率被认为是显着较高的细胞与低PKA活性的所有光强度。(C)2010 Elsevier B. V.保留所有权利。
Light exposure is a potentially powerful stress factor during in vivo optical microscopy studies. In yeast, the general transcription factor Msn2p translocates from the cytoplasm to the nucleus in response to illumination. However, previous time-lapse fluorescence microscopy studies of Msn2p have utilized a variety of discrete exposure settings, which makes it difficult to correlate stress levels and illumination parameters. We here investigate how continuous illumination with blue light, corresponding to GFP excitation wavelengths, affects the localization pattern of Msn2p-GFP in budding yeast. The localization pattern was analyzed using a novel approach that combines wavelet decomposition and change point analysis. It was found that the Msn2p nucleocytoplasmic localization trajectories for individual cells exhibit up to three distinct and successive states; i) Msn2p localizes to the cytoplasm; ii) Msn2p rapidly shuttles between the cytoplasm and the nucleus; iii) Msn2p localizes to the nucleus. Many cells pass through all states consecutively at high light intensities, while at lower light intensities most cells only reach states i) or ii). This behaviour strongly indicates that continuous light exposure gradually increases the stress level over time, presumably through continuous accumulation of toxic photoproducts, thereby forcing the cell through a bistable region corresponding to nucleocytoplasmic oscillations. We also show that the localization patterns are dependent on protein kinase A (PKA) activity, i.e. yeast cells with constantly low PKA activity showed a stronger stress response. In particular, the nucleocytoplasmic oscillation frequency was found to be significantly higher for cells with low PKA activity for all light intensities. (C) 2010 Elsevier B.V. All rights reserved.