The present invention provides methods and systems that uses
transgenic zebrafish with an easily assessable
reporter gene under the control of
pollutant-inducible
DNA response elements.
Transgenic zebrafish, carrying
pollution-inducible response elements, are placed in the water to be tested, and the contaminants become bioconcentrated (generally 1,000- to 40,000-fold, relative to the water) in the tissues of the fish thereby activating specific response elements, which up-regulate the LUC
reporter gene. Fish are then removed from the test water and placed immediately in a luminometer
cuvette and incubated with
luciferin.
Luciferin is rapidly taken up into the tissues of the fish, oxidized by
luciferase, and light is produced. The
luminescence is proportional to the environmental concentration of the
pollutant (to which the fish had been exposed), which drives the expression of the LUC
gene by means of the various
DNA motifs. The
luminescence is quantitated in the luminometer. In each
response element-containing construct, a specific class of polluting chemicals, allowing for differential identification of pollutants in a complex mixture activates the expression of the LUC
gene. This
assay does not require killing the fish and allows for repeated analysis of the same site with the same fish. The sensitivity of the
system can be manipulated by varying the sequence of the
response element.