Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, 18008 Granada, Spain.
J Exp Bot. 2011 Mar;62(6):2039-51. doi: 10.1093/jxb/erq394. Epub 2010 Dec 31.
Chloroplastic thioredoxins f and m (TRX f and TRX m) mediate light regulation of carbon metabolism through the activation of Calvin cycle enzymes. The role of TRX f and m in the activation of Calvin cycle enzymes is best known among the TRX family. However, the discoveries of new potential targets extend the functions of chloroplastic TRXs to other processes in non-photosynthetic tissues. As occurs with numerous chloroplast proteins, their expression comes under light regulation. Here, the focus is on the light regulation of TRX f and TRX m in pea and Arabidopsis during the day/night cycle that is maintained during the subjective night. In pea (Pisum sativum), TRX f and TRX m1 expression is shown to be governed by a circadian oscillation exerted at both the transcriptional and protein levels. Binding shift assays indicate that this control probably involves the interaction of the CCA1 transcription factor and an evening element (EE) located in the PsTRX f and PsTRX m1 promoters. In Arabidopsis, among the multigene family of TRX f and TRX m, AtTRX f2 and AtTRX m2 mRNA showed similar circadian oscillatory regulation, suggesting that such regulation is conserved in plants. However, this oscillation was disrupted in plants overexpressing CCA1 (cca1-ox) or repressing CCA1 and LHY (cca1-lhy). The physiological role of the oscillatory regulation of chloroplastic TRX f and TRX m in plants during the day/night cycle is discussed.
质体硫氧还蛋白 f 和 m（TRX f 和 TRX m）通过激活卡尔文循环酶来介导光对碳代谢的调节。在硫氧还蛋白家族中，TRX f 和 TRX m 对卡尔文循环酶的激活作用最为人所知。然而，新的潜在靶标的发现将质体 TRXs 的功能扩展到非光合组织中的其他过程。与许多质体蛋白一样，它们的表达受光调节。这里的重点是在豌豆和拟南芥白天/黑夜周期中 TRX f 和 TRX m 的光调节，这种调节在主观夜晚期间得以维持。在豌豆（Pisum sativum）中，TRX f 和 TRX m1 的表达被证明受到转录和蛋白水平上的昼夜振荡的控制。结合移位分析表明，这种控制可能涉及 CCA1 转录因子与位于 PsTRX f 和 PsTRX m1 启动子中的傍晚元件（EE）的相互作用。在拟南芥中，TRX f 和 TRX m 的多基因家族中，AtTRX f2 和 AtTRX m2 mRNA 表现出相似的昼夜振荡调节，表明这种调节在植物中是保守的。然而，这种振荡在过表达 CCA1（cca1-ox）或抑制 CCA1 和 LHY（cca1-lhy）的植物中被打乱。讨论了白天/黑夜周期中植物质体 TRX f 和 TRX m 振荡调节的生理作用。
