Figure 1

The diagram of gene replacement and Southern blot analysis. (A) Diagram of gene replacement of ste7 with gtf originated from Streptococcus thermophilus through a double crossover via homologous recombination. Gray box indicates the location of Km^r gene in Streptomyces sp. 139 (ste7 ^-). Restriction maps of Streptomyces sp. 139 (ste7 ^-) and the gene replacement strain Streptomyces sp. 139 (gtf) show the predicted fragment sizes upon Bam HI digestion. (B) Southern blot autoradiograph of Streptomyces sp. 139 (ste7 ^-) and Streptomyces sp. 139 (gtf). 1. Chromosome DNA of Streptomyces sp. 139 (ste7 ^-) digested with Bam HI; 2. chromosome DNA of Streptomyces sp. 139 (gtf) digested with Bam HI.