Replication of the nonconjugative plasmid RSF1010 in Escherichia coli K-12

Abstract
Replicating DNA molecules of the nonconjugative F plasmid RSF1010 (Smr [streptomycin resistance] Sur [sulfonamide resistance] were cleaved with the EcoRI restriction endonuclease and examined by EM. Results of this analysis indicated that replication is initiated from an origin located at about 19% of total genome size from 1 of the EcoRI ends. Replication proceeded unidirectionally or bidirectionally with equal frequency. Results of the analysis of replicative intermediates of RSF1010 containing the Apr[ampicillin resistance]-transposable sequence (Tn) are also presented.