Ulm Roman, Baumann Alexander, Oravecz Attila, Máté Zoltán, Adám Eva, Oakeley Edward J, Schäfer Eberhard, Nagy Ferenc
Institute of Biology II/Botany, University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany.
Proc Natl Acad Sci U S A. 2004 Feb 3;101(5):1397-402. doi: 10.1073/pnas.0308044100. Epub 2004 Jan 22.
The light environment is a key factor that governs a multitude of developmental processes during the entire life cycle of plants. An important and increasing part of the incident sunlight encompasses a segment of the UV-B region (280-320 nm) that is not entirely absorbed by the ozone layer in the stratosphere of the earth. This portion of the solar radiation, which inevitably reaches the sessile plants, can act both as an environmental stress factor and an informational signal. To identify Arabidopsis genes involved in the UV response, we monitored the gene expression profile of UV-B-irradiated seedlings by using high-density oligonucleotide microarrays comprising almost the full Arabidopsis genome (>24,000 genes). A robust set of early low-level UV-B-responsive genes, 100 activated and 7 repressed, was identified. In all cases analyzed, UV-B induction was found to be independent of known photoreceptors. This group of genes is suggested to represent the molecular readout of the signaling cascade triggered by the elusive UV-B photoreceptor(s). Moreover, our analysis identified interactions between cellular responses to different UV-B ranges that led us to postulate the presence of partially distinct but interacting UV-B perception and signaling mechanisms. Finally, we demonstrate that the bZIP transcription factor HY5 is required for UV-B-mediated regulation of a subset of genes.
光照环境是在植物整个生命周期中控制众多发育过程的关键因素。入射阳光中一个重要且占比不断增加的部分包含紫外线B区域（280 - 320纳米）的一段，这部分光线不能被地球平流层中的臭氧层完全吸收。这部分不可避免地到达固着植物的太阳辐射，既可以作为一种环境胁迫因子，也可以作为一种信息信号。为了鉴定拟南芥中参与紫外线反应的基因，我们通过使用包含几乎整个拟南芥基因组（超过24,000个基因）的高密度寡核苷酸微阵列，监测了紫外线B照射幼苗的基因表达谱。我们鉴定出了一组稳定的早期低水平紫外线B反应基因，其中100个被激活，7个被抑制。在所有分析的案例中，发现紫外线B诱导独立于已知的光感受器。这组基因被认为代表了由难以捉摸的紫外线B光感受器触发的信号级联反应的分子读数。此外，我们的分析确定了细胞对不同紫外线B范围反应之间的相互作用，这使我们推测存在部分不同但相互作用的紫外线B感知和信号传导机制。最后，我们证明bZIP转录因子HY5是紫外线B介导的部分基因调控所必需的。
