Cloning and characterization of an amplified DNA sequence in chromosomal DNA of Streptomyces aureofaciens 2201

In strain 2201 of Streptomyces aureofaciens, a high copy number amplified DNA sequence (ADS-Sa2201) was found and characterized. The amplified sequence in the chromosomal DNA of this strain forms a stretch of about 10 kb tandemly repeated 100-500 times. In this strain also, extrachromosomal copies of the repeated unit of the ADS-Sa2201 were found. In cloning experiments any autonomous replicon was found on ADS-Sa2201 and it thus can be presumed that the presence of the extrachromosomal copies of the repeated unit of ADS-Sa2201 is only a result of its excision from the chromosome. A part of the repeated unit of ADS-Sa2201 was also found in chromosomal DNA of strain 13 of S. aureofaciens. In this strain no part of ADS-Sa2201 is present extrachromosomally.