Elevation of cytosolic calcium precedes anoxic gene expression in maize suspension-cultured cells.
Elevation of cytosolic calcium precedes anoxic gene expression in maize suspension-cultured cells.
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DOI：
10.1105/tpc.6.12.1747
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发表时间：
1994-12
期刊：
影响因子：
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通讯作者：
C. Subbaiah;Douglas S. Bush;Martin M. Sachs
中科院分区：
文献类型：
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作者：
C. Subbaiah;Douglas S. Bush;Martin M. Sachs
基于药理学证据，我们以前提出，细胞内Ca 2+介导的感知在玉米幼苗的O2剥夺。在此，利用荧光成像和玉米悬浮培养细胞中Ca 2+的光度法，对该方案进行了进一步研究。采用了两种互补的方法：（1）缺氧诱导的细胞内Ca 2+浓度（[Ca]i）变化的真实的时间分析和（2）[Ca]i的实验操作，然后测定所得的缺氧特异性反应。O2耗竭导致[Ca 2 +]i立即增加，这在复氧后几秒钟内是可逆的。[Ca]i升高的进行与细胞外Ca 2+无关。Ca 2+反应的动力学表明，它发生得比任何可检测到的基因表达的变化早得多。钌红阻断缺氧[Ca]i升高，也阻断adh 1（编码乙醇脱氢酶）和sh 1（编码蔗糖合成酶）mRNA的诱导。Ca ~（2+）与钌红一起沿着加入时，可阻止拮抗剂对缺氧反应的影响。维拉帕米和苄普地尔未能阻断缺氧诱导的[Ca]i升高，对缺氧基因表达同样无效。常氧条件下，咖啡因引起[Ca]i和ADH活性升高。这些数据提供了直接的证据[Ca]i升高玉米细胞作为缺氧诱导的动员钙从细胞内存储的结果。此外，任何修改[Ca]i上升的操作都会导致两个缺氧诱导基因表达的平行变化。因此，这些结果证实了我们的建议，[Ca]i是植物缺氧信号的生理传感器。
Based on pharmacological evidence, we previously proposed that intracellular Ca2+ mediates the perception of O2 deprivation in maize seedlings. Herein, using fluorescence imaging and photometry of Ca2+ in maize suspension-cultured cells, the proposal was further investigated. Two complementary approaches were taken: (1) real time analysis of anoxia-induced changes in cytosolic Ca2+ concentration ([Ca]i) and (2) experimental manipulation of [Ca]i and then assay of the resultant anoxia-specific responses. O2 depletion caused an immediate increase in [Ca2+]i, and this was reversible within a few seconds of reoxygenation. The [Ca]i elevation proceeded independent of extracellular Ca2+. The kinetics of the Ca2+ response showed that it occurred much earlier than any detectable changes in gene expression. Ruthenium red blocked the anoxic [Ca]i elevation and also the induction of adh1 (encoding alcohol dehydrogenase) and sh1 (encoding sucrose synthase) mRNA. Ca2+, when added along with ruthenium red, prevented the effects of the antagonist on the anoxic responses. Verapamil and bepridil failed to block the [Ca]i rise induced by anoxia and were equally ineffective on anoxic gene expression. Caffeine induced an elevation of [Ca]i as well as ADH activity under normoxia. The data provide direct evidence for [Ca]i elevation in maize cells as a result of anoxia-induced mobilization of Ca2+ from intracellular stores. Furthermore, any manipulation that modified the [Ca]i rise brought about a parallel change in the expression of two anoxia-inducible genes. Thus, these results corroborate our proposal that [Ca]i is a physiological transducer of anoxia signals in plants.