Ehira Shigeki, Ohmori Masayuki, Sato Naoki
Department of Biochemistry and Molecular Biology, Faculty of Science, Saitama University, 255 Shimo-Ohkubo, Sakura, Saitama, 338-8570 Japan.
Plant Cell Physiol. 2005 Aug;46(8):1237-45. doi: 10.1093/pcp/pci132. Epub 2005 May 26.
Most organisms have developed various strategies to react rapidly to temperature down-shift and regulate expression of various genes to acclimate to low temperature. In photosynthetic organisms, temperature down-shift in the light results in not only a decrease in growth temperature but also an increase in PSII excitation pressure. Distinguishing the effects of low temperature from the effects of excitation pressure is necessary to understand the mechanism of low-temperature signal transduction. In this report, we analyzed changes in gene expression after three different environmental changes, i.e. temperature down-shift in the light, temperature down-shift in the dark and transfer to the dark, using DNA microarray in the cyanobacterium Anabaena sp. strain PCC 7120. By comparing the expression patterns under the three experimental conditions, we identified 15 open reading frames (ORFs) that were up-regulated by temperature down-shift both in the light and in the dark. These ORFs are considered to be regulated by low temperature, but not by excitation pressure. Six of them have a consensus sequence within the upstream region of their coding region and were indicated also to be up-regulated by tetracycline. Functional or structural changes in the ribosome could affect transcript levels of the low-temperature-regulated ORFs.
大多数生物已发展出各种策略来快速应对温度下降，并调节各种基因的表达以适应低温。在光合生物中，光照下的温度下降不仅会导致生长温度降低，还会使光系统II（PSII）的激发压力增加。区分低温效应和激发压力效应对于理解低温信号转导机制至关重要。在本报告中，我们使用DNA微阵列技术，分析了蓝藻鱼腥藻PCC 7120在三种不同环境变化后基因表达的变化，这三种环境变化分别是光照下的温度下降、黑暗中的温度下降以及转移至黑暗环境。通过比较这三种实验条件下的表达模式，我们鉴定出15个开放阅读框（ORF），它们在光照和黑暗条件下均因温度下降而上调。这些ORF被认为是受低温调控，而非激发压力调控。其中六个在其编码区上游区域具有共有序列，并且还表明它们会被四环素上调。核糖体的功能或结构变化可能会影响低温调控的ORF的转录水平。
