Differential gene expression of Chlamydomonas reinhardtii in response to 2,4,6-trinitrotoluene (TNT) using microarray analysis

The exposure of Chlamydomonas reinhardtii to environmental stress, such as that caused by the explosive 2,4,6-trinitrotoluene (TNT) can alter its gene expression. Expression analysis was conducted using a microarray composed of 3079 Chlamydomonas ESTs to characterize the broad range of responses of gene expression exposed to this common ordnance compound. TNT treatment conditions were determined by growth analysis of Chlamydomonas in 0-5 mug/mL TNT. One and 3 mug/mL were used for microarray analysis since 1 mug/mL of TNT did not decrease the cell count after 7 days of treatment, whereas 3 mug/mL of TNT was the maximum TNT concentration that allowed growth, respectively. Transcriptional profiling revealed that approximately 158 responsive genes were differentially expressed representing several functional categories. Genes responsible for photosynthesis, energy metabolism and oxidative stress were upregulated in the presence of TNT, while the expression of cell wall related genes were down-regulated. Several unidentified genes were also affected. The microarray results were validated using real-time RT-PCR for a subset of genes. Information from the microarray analysis can be used to engineer algae-based sensors to signal TNT exposure in addition to potential explosives cleanup applications. (C) 2004 Elsevier Ireland Ltd. All rights reserved.