Metal-induced expressing of mammal Metallothionein-1 gene in cyanobacteria to promote cadmium-binding preferences

• Published in: Applied microbiology and biotechnology 1999-11, Vol.52 (6), p.806-810
• Main Authors: GUO, X.-X, SHI, D.-J, XU, X.-D, OUYANG, Y.-X, RU, B.-G
• Format: Article
• Language: English
• Subjects: Anabaena; Bacteria; Biological and medical sciences; Biotechnology; Cadmium; Cyanobacteria; Fundamental and applied biological sciences. Psychology; Genetic engineering; Genetic technics; metallothionein 1; Metals; Methods. Procedures. Technologies; Modification of gene expression level; Proteins; smtA gene; Zinc
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s002530051596

The metal(zinc)-inducible smtA gene promoter (smt O-P) from cyanobacteria was applied for the expression of mouse MT-1 cDNA in the filamentous cyanobacterium Anabaena sp. PCC 7120 to enhance its metal-binding capability and to change its main binding specificity from zinc to cadmium. Shuttle expression vector pKT-MRE transformed the cyanobacterial cells by triparent conjugal transfer. Positive clones were screened and identified by streptomycin, DNA dot blot, SDS-PAGE and Western blot analysis. Photosynthetic oxygen evolution and metal atom absorption indicated that under the cadmium stress the metal-induced expression of foreign mMT-1 doubled their cadmium resistance and developed cells showing a much higher preference to absorb cadmium other than zinc in medium. The cadmium content in cell extract rose from 11% to 36%, and the cadmium cleared from media by transgenic cells rose from 18% to 62%. There was only a slight enhancement for zinc binding in the wild or transgenic type.[PUBLICATION ABSTRACT]