ANALYSIS OF PUTATIVE DNA AMPLIFICATION GENES IN THE ELEMENT AUD1 OF STREPTOMYCES-LIVIDANS-66

The amplifiable AUDI element of Streptomyces lividans 66 consists of t wo copies of a 4.7 kb sequence flanked by three copies of a 1 kb seque nce. The DNA sequences of the three 1 kb repeats were determined. Two copies (left and middle repeats) were identical:(1009 bp in length) an d the right repeat was 1012 bp long and differed at 63 positions. The repeats code for open reading frames (ORFs) with typical Streptomyces codon usage, which would encode proteins of about 36 kD molecular weig ht. The sequences of these ORFs suggest that they specify DNA-binding proteins and potential palindromic binding sites are found adjacent to the genes. The putative amplification protein encoded by the right re peat was expressed in Escherichia coli.