Environmental Stresses Modulate Abundance and Timing of Alternatively Spliced Circadian Transcripts in Arabidopsis
Environmental Stresses Modulate Abundance and Timing of Alternatively Spliced Circadian Transcripts in Arabidopsis
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DOI：
10.1016/j.molp.2014.10.011
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发表时间：
2015-02-02
期刊：
影响因子：
27.5
通讯作者：
Mockler, Todd C.
中科院分区：
文献类型：
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作者：
Filichkin, Sergei A.;Cumbie, Jason S.;Mockler, Todd C.
环境胁迫深刻地改变了拟南芥中包括内含子保留（IR）转录本在内的无义mRNA的积累。使用振荡和非振荡转录本解剖了应激诱导的IR mRNA的时间模式。大范围的热循环触发了长IR CCA 1亚型的急剧增加，并将其相位改变为一天中的不同时间。非生物和生物胁迫，如干旱或假单胞菌感染诱导类似的增加。热应力诱导的时间延迟，在积累的CCA 1 I4 Rb转录本，而功能的mRNA显示稳定的振荡。我们的数据有利于一个假设，即应力引起的中央振荡器的不稳定性，可以部分补偿通过波动的丰富和异相振荡的CCA 1 IR成绩单。两者合计，我们的研究结果支持一个概念，mRNA丰度可以通过改变功能和无义/IR转录本之间的比例进行调节。SR 45蛋白在体外特异性结合于保留的CCA 1内含子，表明该剪接因子可能参与内含子保留的调节。无义介导的mRNA衰变（NMD）受损和热应激植物的转录组共享一组与应激和防御诱导转录相关的保留内含子。NMD突变体中某些应激反应网络的组成性激活可能与功能性和无义mRNA之间的不平衡有关。
Environmental stresses profoundly altered accumulation of nonsense mRNAs including intron-retaining (IR) transcripts in Arabidopsis. Temporal patterns of stress-induced IR mRNAs were dissected using both oscillating and non-oscillating transcripts. Broad-range thermal cycles triggered a sharp increase in the long IR CCA1 isoforms and altered their phasing to different times of day. Both abiotic and biotic stresses such as drought or Pseudomonas syringae infection induced a similar increase. Thermal stress induced a time delay in accumulation of CCA1 I4Rb transcripts, whereas functional mRNA showed steady oscillations. Our data favor a hypothesis that stress-induced instabilities of the central oscillator can be in part compensated through fluctuations in abundance and out-of-phase oscillations of CCA1 IR transcripts. Taken together, our results support a concept that mRNA abundance can be modulated through altering ratios between functional and nonsense/IR transcripts. SR45 protein specifically bound to the retained CCA1 intron in vitro, suggesting that this splicing factor could be involved in regulation of intron retention. Transcriptomes of nonsense-mediated mRNA decay (NMD)-impaired and heat-stressed plants shared a set of retained introns associated with stress-and defense-inducible transcripts. Constitutive activation of certain stress response networks in an NMD mutant could be linked to disequilibrium between functional and nonsense mRNAs.