Cloning of Streptomyces DNA into Escherichia coli: Absence of Heterospecific Gene Expression of Streptomyces Genes in E. coli

Abstract

The cleavage pattern of Streptomyces chromosomal DNA was examined with various restriction endonucleases under agarose gel electrophoresis, and SalI endonuclease was found to cleave Streptomyces DNA efficiently. Chromosomal DNA segments from four Streptomyces species were cloned into Escherichia coli vector plasmids pTA2070 and pBR322 by the “Sall-ligase method.” The number of clones possessing hybrid plasmids was large enough to be termed as a gene bank. However, there was no clone in the four gene banks complementing E. coli leu, ade, or thy auxotrophic marker. No clone was isolated that expressed the streptomycin phosphotransferase activity of Streptomyces griseus as a determinant of streptomycin resistance in E. coli. It was suggested that E. coli does not allow functional expression of Streptomyces genes.

A streptomycin resistant plasmid RSF1010 of E. coli was linked to a pTA2070-S. griseus DNA hybrid plasmid, by the “EcoRI-ligase method,” in order to construct a possible cloning vector usable in the streptomycete.