Zinc-Induced Activation of Rainbow Trout Metallothionein-A Promoter in Transgenic Medaka

Abstract

Zinc-induced activation of rainbow trout metallothionein-A (rtMT-A) promoter was investigated in transgenic medaka using chloramphenicol acetyltransferase (CAT) gene as a reporter. The plasmid prtMT-A-CAT containing rtMT-A promoter and CAT gene was microinjected into medaka fertilized eggs at the one-cell stage. Hatched fry, in which the transgene was detected by PCR, were exposed to 0 to 100 μM of ZnCl₂ and the promoter activity was monitored by CAT assay. The activity was induced dose-dependently at concentrations of ZnCl₂ over 1 μM. These results suggest that the rtMT-A promoter was useful for controlling expression of transgenes in transgenic fish by experimental conditions.