AbstractInterest in the biology of theStreptomycesand application of these soil bacteria to production of commercial antibiotics and enzymes has stimulated the development of efficient cloning techniques and a variety of streptomycete plasmid and phage vectors.Streptomyces lividansis routinely employed as a host for gene cloning, largely because this species recognizes a large number of promoters and appears to lack a restriction system. Vector pIJ702 was constructed from a variant of a larger autonomous plasmid and is often used as a cloning vehicle in conjunction withS. lividans. The host range of vector pIJ702 extends beyondStreptomycesspp., and its high copy number has been exploited for the overproduction of cloned gene products. This combination of host and vector has been used successfully to investigate antibiotic biosynthesis, gene structure and expression, and to map variousStreptomycesmutants.