Sørensen Jesper G, Nielsen Morten M, Kruhøffer Mogens, Justesen Just, Loeschcke Volker
Aarhus Centre for Environmental Stress Research, Department of Ecology and Genetics, University of Aarhus, Ny Munkegade, Denmark.
Cell Stress Chaperones. 2005 Winter;10(4):312-28. doi: 10.1379/csc-128r1.1.
The availability of full genome sequences has allowed the construction of microarrays, with which screening of the full genome for changes in gene expression is possible. This method can provide a wealth of information about biology at the level of gene expression and is a powerful method to identify genes and pathways involved in various processes. In this study, we report a detailed analysis of the full heat stress response in Drosophila melanogaster females, using whole genome gene expression arrays (Affymetrix Inc, Santa Clara, CA, USA). The study focuses on up- as well as downregulation of genes from just before and at 8 time points after an application of short heat hardening (36 degrees C for 1 hour). The expression changes were followed up to 64 hours after the heat stress, using 4 biological replicates. This study describes in detail the dramatic change in gene expression over time induced by a short-term heat treatment. We found both known stress responding genes and new candidate genes, and processes to be involved in the stress response. We identified 3 main groups of stress responsive genes that were early-upregulated, early-downregulated, and late-upregulated, respectively, among 1222 differentially expressed genes in the data set. Comparisons with stress sensitive genes identified by studies of responses to other types of stress allow the discussion of heat-specific and general stress responses in Drosophila. Several unexpected features were revealed by this analysis, which suggests that novel pathways and mechanisms are involved in the responses to heat stress and to stress in general. The majority of stress responsive genes identified in this and other studies were downregulated, and the degree of overlap among downregulated genes was relatively high, whereas genes responding by upregulation to heat and other stress factors were more specific to the stress applied or to the conditions of the particular study. As an expected exception, heat shock genes were generally found to be upregulated by stress in general.
全基因组序列的可得性使得微阵列得以构建，利用微阵列可以在全基因组范围内筛选基因表达的变化。这种方法能够在基因表达水平上提供大量有关生物学的信息，是识别参与各种过程的基因和通路的有力方法。在本研究中，我们使用全基因组基因表达阵列（美国加利福尼亚州圣克拉拉市的Affymetrix公司）报告了对黑腹果蝇雌性个体完整热应激反应的详细分析。该研究聚焦于在施加短期热硬化（36摄氏度，1小时）之前及之后的8个时间点基因的上调和下调情况。在热应激后长达64小时跟踪表达变化，使用了4个生物学重复样本。本研究详细描述了短期热处理随时间诱导的基因表达的显著变化。我们发现了已知的应激反应基因和新的候选基因，以及参与应激反应的过程。在数据集中1222个差异表达基因中，我们分别鉴定出了3组主要的应激反应基因，即早期上调、早期下调和晚期上调的基因。与通过对其他类型应激反应研究鉴定出的应激敏感基因进行比较，有助于讨论果蝇中的热特异性应激反应和一般应激反应。该分析揭示了几个意想不到的特征，这表明新的通路和机制参与了对热应激以及一般应激的反应。在本研究和其他研究中鉴定出的大多数应激反应基因是下调的，下调基因之间的重叠程度相对较高，而对热和其他应激因素上调反应的基因则更特定于所施加的应激或特定研究的条件。作为一个预期的例外，热休克基因通常在一般应激下被上调。
