[Polycyclic musks exposure affects gene expression of specific proteins in earthworm Eisenia fetida]

To investigate the changes in gene expression of earthworm specific proteins following long-term exposure to low-dose polycyclic musks in soil, the mRNA expression levels of the four representative protein-coding genes (HSP70, CRT, cyPA, TCTP) were examined in earthworm Eisenia fetida exposed to polycyclic musks using real-time quantitative PCR (RT-qPCR). The purpose of this study was to investigate mRNA expression profiles of test protein genes in response to sublethal galaxolide (HHCB) and tonalide (AHTN) for 28 d exposure. The analysis results of both sequence alignment and melting curves of RT-qPCR reactions showed that the selected primers were appropriately qualified for quantitative mRNA analysis. mRNA expressions of HSP70 gene were not significantly changed in Eisenia fetida exposed to low concentrations of AHTN (less than 30 microg x g(-1)) and HHCB (less than 50 microg x g(-1)). But HSP70 gene expressions were significantly down-regulated at concentrations of AHTN or HHCB equal to or greater than 30 or 50 microg x g(-1). However, up-regulation of CRT gene expressions was induced in response to all test concentrations of AHTN and HHCB. Both cyPA and TCTP gene expressions were not varied compared to control groups after 28 days of exposure. Overall, the results indicated that HSP70 and CRT genes expression patterns might be potential early molecular biomarkers for predicting the harmful exposure level and ecotoxicological effects of polycyclic musks contaminated soil.