Isolation and characterization of Streptomyces fradiae plasmids which are prophage of the actinophage phiSF1

Abstract

Two plasmids, designated pUC1 and pUC13, have identified as different prophage states of the Streptomyces fradiae actinophage phiSF1. Plasmids pUC1 and pUC13, 51.1 Md, are identical as determined by restriction endonuclease analysis and other criteria. They differ in that while pUC1 specifies "type A" plaques, characterized by a narrow zone of growth inhibition around a transformant colony, pUC13 specifies "type B" plaques, characterized by concentric rings of growth and growth inhibition around a transformant colony. Additionally cultures carrying pUC13 release antinophage phiSF1 at a frequency about 10 3-10 4 times that pUC1 containing cultures. Restriction enzyme digestion, transfection, and transformation analyses show that phiSF1 DNA, 55.7 Md, is about 8-10% larger than pUC13 and appears to be circularly permuted and terminally redundant. The pUC1 and pUC13 prophage are interconvertible.