DNA cloning in Streptomyces: a bifunctional replicon comprising pBR322 inserted into a Streptomyces phage

Abstract

The Gram-positive, mycelial, differentiating streptomycetes are responsible for the production of many important antibiotics. The availability of gene cloning systems in this microbial group would have many industrial applications¹ besides allowing more penetrating study of the genetics of Streptomyces coelicolor A3(2) (which, as the best understood streptomycete genetically, serves as a model for much other Streptomyces genetics)². Recent successes^3,4 (see previous paper⁴) in introducing Streptomyces DNA into S. coelicolor and Streptomyces lividans on plasmid vectors would be nicely complemented by the availability of Streptomyces bacteriophage vectors (discussed in ref. 5): for example, many phages have wide and easily defined host ranges; heat-inducible prophages might be used to give high copy number of cloned DNA; efficient phage promoters might be used to increase gene expression; there may be differential stabilities for particular DNA sequences cloned in plasmids vis-à-vis phages; selective insertion of DNA, utilizing packaging constraints, may be possible with phages; and in situ hybridization⁶ of radioactive probes to DNA in plaques is likely to be simple. We describe here the use of the moderately wide host range temperate phage, ΦC31⁷, for this purpose.