PARENT SESSION
MP6 - Transgenic Organisms as Environmental Biosensors
Chair: Jackson, David¹, ¹ 568 Doughten Drive, Ft. Detrick, MD, USA
Co-chair: van der Schalie, William², ² 568 Doughten Drive, Ft. Detrick, MD
2:10 PM to 5:30 PM - Monday, 18 November 2002
Room Ballroom B

(294) Pollution inducible transgenes in zebrafish.

Carvan, Michael^*,1, ¹ University of Wisconsin-Milwaukee Great Lakes WATER Institute, Milwaukee, WI, USA

ABSTRACT- We are developing transgenic lines of zebrafish in which DNA motifs that respond to selected environmental pollutants are capable of activating a reporter gene that can be easily assayed. We have begun with three response elements that recognize three important classes of foreign chemicals. Aromatic hydrocarbon response elements (AHREs) respond to numerous polycyclic hydrocarbons and halogenated coplanar molecules such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin) and polychlorinated biphenyls. Electrophile response elements (EPREs) respond to quinones and numerous other potent electrophilic oxidants. Metal response elements (MREs) respond to heavy metal cations such as mercury, copper, nickel, cadmium and zinc. Each of these substances is known to be bioconcentrated in fish to varying degrees; for example, 10^-17 molar TCDD in a body of water becomes concentrated to approximately 10^-12 molar TCDD in a fish where it would act upon the AHRE motif and turn on the luciferase (LUC) reporter gene. The living fish as a sentinel will not only be assayed intact in the luminometer, but would likely be usable again after several days or weeks of depuration. To date, we have established that zebrafish transcription factors are able to recognize both mammalian and trout AHRE, EPRE, and MRE sequences in a dose-dependent and chemical-class-specific manner, and that expression of both the LUC and jellyfish green fluorescent protein (GFP) reporter genes are easily detected in zebrafish cell cultures and in the intact live zebrafish. Variations in sensitivity of this model system can be achieved by increasing the copy number of response elements, and perhaps by altering the sequence of each core consensus response element and flanking regions. This transgenic technology should allow for a simple, exquisitely sensitive, and inexpensive assay for monitoring aquatic pollution.

Key words: zebrafish, transgenics, reporter genes, sentinel organisms