Zhang Xiao-Ning, Wu Yingjie, Tobias John W, Brunk Brian P, Deitzer Gerald F, Liu Dongmei
Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
PLoS One. 2008;3(10):e3563. doi: 10.1371/journal.pone.0003563. Epub 2008 Oct 30.
Cryptochromes are blue light photoreceptors involved in development and circadian clock regulation. They are found in both eukaryotes and prokaryotes as light sensors. Long Hypocotyl in Far-Red 1 (HFR1) has been identified as a positive regulator and a possible transcription factor in both blue and far-red light signaling in plants. However, the gene targets that are regulated by HFR1 in cryptochrome 1 (cry1)-mediated blue light signaling have not been globally addressed. We examined the transcriptome profiles in a cry1- and HFR1-dependent manner in response to 1 hour of blue light. Strikingly, more than 70% of the genes induced by blue light in an HFR1-dependent manner were dependent on cry1, and vice versa. High overrepresentation of W-boxes and OCS elements were found in these genes, indicating that this strong cry1 and HFR1 co-regulation on gene expression is possibly through these two cis-elements. We also found that cry1 was required for maintaining the HFR1 protein level in blue light, and that the HFR1 protein level is strongly correlated with the global gene expression pattern. In summary, HFR1, which is fine-tuned by cry1, is crucial for regulating global gene expression in cry1-mediated early blue light signaling, especially for the function of genes containing W-boxes and OCS elements.
隐花色素是参与植物发育和昼夜节律调控的蓝光感受器。它们作为光传感器存在于真核生物和原核生物中。远红光下长下胚轴1（HFR1）已被确定为植物蓝光和远红光信号传导中的正向调节因子及可能的转录因子。然而，在隐花色素1（cry1）介导的蓝光信号传导中受HFR1调控的基因靶点尚未得到全面研究。我们以cry1和HFR1依赖的方式检测了响应1小时蓝光的转录组图谱。令人惊讶的是，超过70%以HFR1依赖方式被蓝光诱导的基因依赖于cry1，反之亦然。在这些基因中发现W盒和OCS元件高度富集，表明cry1和HFR1对基因表达的这种强共调控可能是通过这两个顺式元件实现的。我们还发现cry1是蓝光下维持HFR1蛋白水平所必需的，并且HFR1蛋白水平与整体基因表达模式密切相关。总之，由cry1微调的HFR1对于调控cry1介导的早期蓝光信号传导中的整体基因表达至关重要，特别是对于含有W盒和OCS元件的基因的功能。
