Plant & Animal Genome IX Conference

Poster: Transformation
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CALCIUM CHLORIDE INDUCTION OF AN ENHANCED GREEN FLUORESCENT PROTEIN GENE DRIVEN BY THE METALLOTHIONEIN PROMOTER

Purdue University, 1151 Lilly Hall, West Lafayette, IN, 47907, USA

Many of the initial experiments with transgenic animals used a combination of a metallothionein promoter and a growth hormone gene. This promoter was chosen for its inducibility by the presence of heavy metals (i.e. zinc, cadmium, lead, and copper). However, there were concerns that the promoter was active, even in the absence of such heavy metals. The sockeye salmon metallothionein promoter was used to drive the enhanced green fluorescent protein (eGFP) gene in transfected Chinese Hamster Ovarian (CHO) cells. Aberrant expression of the transgene shortly after calcium-phosphate transfection, and in the absence of heavy metals, was noted. After establishment of stable transfected cell lines, we found that concentrations as low as 12.5mM of calcium chloride were sufficient to induce eGFP expression under control of this promoter. Thus, it is possible that leaky expression of metallothionein driven transgenes is the result of calcium-based induction.