title: Replication of the Streptomyces plasmid pSN22 through single-stranded intermediates.
abstract: The replication of the 11 kb conjugative multicopy Streptomyces plasmid pSN22 was analyzed. Mutation and complementation analyses indicated that the minimal region essential for plasmid replication was located on a 1.9 kb fragment of pSN22, containing a transacting element encoding a replication protein and a cis-acting sequence acting as a replication origin. Southern hybridization showed that minimal replicon plasmids accumulated much more single-stranded plasmid molecules than did wild-type pSN22. Only one strand was accumulated. A 500 bp fragment from the pSN22 transfer region was identified which reduced the relative amount of single-stranded DNA, when added in the native orientation to minimal replicon plasmids. This 500 bp DNA sequence may be an origin for second-strand synthesis. It had no effect on the efficiency of co-transformation, plasmid incompatibility, or stability. The results indicate that pSN22 replicates via single-stranded intermediates by a rolling circle mechanism.
authors.affiliation: International Center of Cooperative Research in Biotechnology, Japan, Osaka.
authors.forename: M
authors.initials: M
authors.lastname: Kataoka
authors.forename: N
authors.initials: N
authors.lastname: Kuno
authors.forename: T
authors.initials: T
authors.lastname: Horiguchi
authors.forename: T
authors.initials: T
authors.lastname: Seki
authors.forename: T
authors.initials: T
authors.lastname: Yoshida
mesh_terms: D004261:DNA Replication / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005816:Genetic Complementation Test; D008954:Models, Biological; D010957:Plasmids / Q000096:biosynthesis* / Q000235:genetics; D012093:Replicon; D015183:Restriction Mapping; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D004277:DNA, Single-Stranded