Arabidopsis possess a small family of five metallothionein genes, as the expression of one of them (MT2a), was reported to be strongly induced by Cu II, ZnII and Cd II ions, (15). In present research, the expression of MT2a promoter region was studied in heterologous genetic background, through analysis of GUS activity of transgenic Nicotiana benthamiana plants carrying MT2a:GUS fusion gene. The fluorimetric GUS assay showed relatively low level of expression of MT2a promoter in the leaves of transgenic plants under non-induced conditions. Strong induction of MT2a:GUS gene, increasing of 103-, 84- and 59- times of the GUS activity, was detected 72 hours after treatment of the transgenic plants with respectively Cu II, ZnII and Cd II ions. The obtained results demonstrate a similarity between the heavy metal induction pattern of MT2a gene in Arabidopsis and MT2a promoter region in N. benthamiana. This suggests conservation of the signal transduction pathway conferring the transcriptional induction of MT2a metallothionein gene by the Cu II, ZnII and Cd II ions, in the both species. The possibilities of the practical utilization of the MT2a promoter region are discussed