Ref ID : 4476
Helen E. David, Adam S. Dawe, David I. de Pomerai, Don Jones, E. Peter, M. Candido, and Clare Daniells; Construction and Evaluation of a Transgenic hsp16-GFP-lacZ Caenorhabditis elegans strain for Environmental Monitoring. Environmental Toxicology & Chemistry 22(1):111-118, 2003
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A novel integrated transgenic Caenorhabditis elegans strain (PC161) incorporates a double reporter construct with green fluorescent protein (GFP) and lacZ genes fused in-frame into the second exon of the hsp16-1 gene. This construct also includes the Simian Virus 40 (SV40) nuclear localized signal such that the fusion protein accumulates in the nuclei of expressing cells. The PC161 strain was used to monitor the effects of several known stressors, including heat, cadmium, and microwave radiation. The time course of induction was similar for both reporters but was strongly influenced by pretreatment conditions. The PC161 worms kept at 15 degrees C beforehand showed a steady increase in reporter expression (up to at least 16 hr) when heated to 30 degrees C. However, if washed on ice prior to heat stress at 30 degrees C, PC161 worms showed a much steeper rise in reporter expression, reaching a maximum after 2.5 hr and then plateauing. Heat shock induced strong expression of both reporter genes in all tissues apart from the germ line and early embryos. A highly significant linear dose-response relationship was observed for both transgenes with increasing cadmium concentrations (5-100 µg/ml). Prolonged exposure to microwave radiation (750 MHz and 0.5 W for 16 hr) also induced expression of both transgenes at 25 and (to some extent) 27 degrees C, but only beta-galactosidase activity was detectable at 23 degrees C, and neither reporter was detectably expressed at 21 degrees C. Throughout all exposure, the lacZ reporter product was more rapidly detectable than coexpressed GFP. However, the GFP reporter affords opportunities to monitor the stress response in living worms.