Replication of coliphage M-13. II. Intracellular deoxyribonucleic acid forms associated with M-13 infection of mitomycin C-treated cells

Abstract

Intracellular deoxyribonucleic acid (DNA) forms associated with bacteriophage M-13 infection have been isolated and characterized. Escherichia coli HF4704 (F(+), hcr(-), thy(-)) cells were treated with mitomycin C to inhibit host-cell DNA synthesis and were then infected with phage M-13. This treatment permitted radioactive labeling of phage-specific DNA forms with (3)H-thymine. These labeled DNA components were characterized by sucrose density sedimentation and equilibrium density gradient centrifugation in neutral and ethidium bromide CsCl gradient. Two double-stranded circular forms were found with properties analogous to the replicative form I and replicative form II of phiX174. A third component, identified as single-stranded DNA, was isolated in some samples removed 45 min after phage synthesis was initiated.