Time-resolved heat stress response of Saccharomyces cerevisiae. Saccharomyces cerevisiae

Whole-genome transcriptional response of S. cerevisiae to an increase in temperature from 28°C to 41°C under well-controlled conditions. Two subsequent phases of response with very different dynamics: a short term response for the first hour after the temperature increase and a long term one for up to six hours. The initial response was strongest with almost half of the ORFs being induced or repressed to a statistically significant level (here 1.5 fold). The data was grouped based on the function of the encoded proteins. Analysis showed that the cells overexpressed genes involved in energy conservation processes. Genes encoding molecular chaperones were overexpressed as well, presumably to counteract the effect of the temperature increase on protein denaturation. Furthermore, genes encoding parts of the translation and transcription systems were repressed temporarily, in line with the observed lag in growth. More detailed analysis of certain small groups of genes involved in energy metabolism supported the notion that, although the expression level of genes represent a part of the stress response, they cannot be directly linked to the level of activity of their products. Overall design: Samples were taken from three replicate control cultures at 28°C at three timepoints and from three replicate stressed cultures at six timepoints

酿酒酵母（S. cerevisiae）在严格可控的培养条件下，由28℃升温至41℃后的全基因组转录响应特征。该温度胁迫响应包含两个动力学特性差异显著的后续阶段：升温后首小时的短期响应，以及最长可达6小时的长期响应。
初始响应的调控强度最高，近半数开放阅读框（Open Reading Frames，ORFs）的表达量发生具有统计学显著性的上调或下调，变化幅度达1.5倍（为本研究设定的显著性阈值）。
研究团队依据编码蛋白的功能对该数据集进行了分组分析。结果显示，细胞过表达参与能量守恒过程的基因；编码分子伴侣（molecular chaperones）的基因同样呈现过表达特征，推测其作用为抵消升温引发的蛋白质变性效应。此外，编码翻译与转录系统组分的基因出现暂时性表达抑制，这与观测到的细胞生长迟滞现象一致。针对能量代谢相关特定小基因簇的更细致分析证实：尽管基因表达水平是应激响应的组成部分，但无法直接与其编码产物的活性水平建立关联。
整体实验设计：在28℃下的三组重复对照培养物中，于三个时间点采集样本；同时在施加温度胁迫的三组重复培养物中，于六个时间点采集样本。