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Synthesis of a bifunctional metallothionein/β‐glucuronidase fusion protein in transgenic tobacco plants as a means of reducing leaf cadmium levels
Author(s) -
Elmayan Taline,
Tepfer Mark
Publication year - 1994
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1994.06030433.x
Subject(s) - nicotiana tabacum , fusion protein , beta glucuronidase , metallothionein , biology , chimeric gene , transgene , glucuronidase , gene , fusion gene , microbiology and biotechnology , green fluorescent protein , reporter gene , gus reporter system , enhancer , genetically modified crops , gene expression , biochemistry , recombinant dna
Chimeric genes under the control of a CaMV 35S promoter with a doubled enhancer (35S 2 ) that encode a mammalian metallothionein (hMTII), or an Escherichia coli β‐glucuronidase (GUS), or a hMTII/GUS fusion protein were introduced into the genome of tobacco ( Nicotiana tabacum cv. PBD6). Transcripts and Cd‐binding proteins of expected size were observed in plants expressing either the 35S 2 ‐hMTII or the 35S 2 hMTII/GUS gene, and in the latter plants a protein with GUS activity that was larger than the native GUS enzyme was observed. Thus, plants expressing the hMTII‐GUS gene synthesize a bifunctional protein, with both GUS and Cd‐binding activity. In an in vitro assay, seedlings expressing either one of these genes had 60–70% lower Cd concentration in their shoots than controls, and Cd translocation to the shoot system was reduced (∼20% of Cd absorbed was translocated), compared with that in controls expressing a 35S 2 ‐GUS gene, where ∼50% of the Cd absorbed was translocated.