LOCATION OF THE GENES FOR ANTHRANILATE SYNTHASE IN STREPTOMYCES-VENEZUELAE ISP5230 - GENETIC-MAPPING AFTER INTEGRATION OF THE CLONED GENES

The anthranilate synthase (trpEG) genes in Streptomyces venezuelae ISP 5230 were located by allowing a segregationally unstable plasmid carry ing cloned S. venezuelae trpEG DNA and a thiostrepton resistance (tsr) marker to integrate into the chromosome. The integrated tsr was mappe d by conjugation and transduction to a location close to tyr-2, betwee n arg-6 and trpA13. A genomic DNA fragment containing trpC from S. ven ezuelae ISP5230 was cloned by complementation of a trpC mutation in St reptomyces lividans. Evidence from restriction enzyme analysis of the cloned DNA fragments, from Southern hybridization using the cloned trp DNA as probes, and from cotransduction frequencies, placed trpEG at a distance of 12-45 kb from the trpCBA cluster. The overall arrangement of tryptophan biosynthesis genes in the S. venezuelae chromosome diff ers from that in other bacteria examined so far.