Expression of mammalian metallothionein genes in Escherichia coli and in Saccharomyces cerevisiae
The metallothionein genes of mouse and human were expressed in Escherichia coli and in Saccharomyces cerevisiae, respectively. The mammalian metallothionein genes code for a group of proteins that are low molecular weight, rich in cysteine and capable of binding heavy metal ions such as cadmium (Cd/sup +2/) and zinc (Zn/sup +2/). Expression of a metallothionein gene renders bacteria and yeast more resistant to heavy metal ions under a variety of growth conditions. This effect is specific for metallothionein because of gene expression is inactivated, bacteria and yeast become sensitive to metals. In addition, bacteria show a preferential incorporation of Cd/sup +2/ ions upon gene expression and contain a protein species that is readily labelled by (/sup 35/S)cysteine. Yeast also contain a protein of a similar molecular weight as the mammalian species but show characteristics that indicate the cells are under stress. Expression of metallothionein has a toxic effect on the microorganism, especially for yeast. The amounts of metallothionein detectable in both bacteria and yeast lysates are low. Several experiments suggest that metallothionein is quickly degraded in the presence of cell lysate. The low level of gene expression and/or the degradation of the gene product make it difficult to detect the expressed metallothionein in the bacterial or yeast lysate. 133 refs., 32 figs., 12 tabs.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6943151
- Report Number(s):
- LBL-22058; ON: DE87008237
- Resource Relation:
- Other Information: Thesis. Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
METALLOTHIONEIN
DNA-CLONING
ENZYME INDUCTION
GENES
ELECTROPHORESIS
ESCHERICHIA COLI
GENE REGULATION
GENETIC ENGINEERING
SACCHAROMYCES CEREVISIAE
BACTERIA
CLONING
FUNGI
METALLOPROTEINS
MICROORGANISMS
ORGANIC COMPOUNDS
PLANTS
PROTEINS
SACCHAROMYCES
YEASTS
550200* - Biochemistry
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