Site-specific integration of the actinophage R4 genome into the chromosome of Streptomyces parvulus upon lysogenization.

The lysogenization of Streptomyces parvulus by actinophage R4 occurs by site-specific integration of the phage genome into the chromosome. The DNA fragments containing the attachment sites on the host chromosome, the phage genome, and the two junctions created by insertion of the phage genome were cloned and sequenced. The attachment sites were found to share a common core of 12 bp. This common core sequence was not detected in chromosomal DNAs of S. coelicolor and S. lividans.