An in vivo assay for conjugation-mediated recombination yields novel results for Streptomyces plasmid pIJ101.
Efficient transmission of circular plasmids in Streptomyces spp. proceeds by an uncharacterized mechanism that requires a cis-acting locus of transfer (clt) and often only a single plasmid-encoded protein. For circular plasmids from other bacteria, site- and strand-specific nicking takes place at the cis-acting oriT locus via the plasmid-encoded relaxase protein prior to single-strand transfer. Using an assay originally designed to demonstrate that conjugative transfer of plasmids containing tandem oriT loci results in the formation of a single composite oriT locus, we show here that an analogous construct involving the pIJ101 clt locus apparently does not undergo such a conjugation-mediated event during plasmid transfer. Our results, which imply that streptomycete plasmids are transferred by a functionally distinct mechanism compared to oriT-containing plasmids, are complementary to other recent evidences that support a novel double-stranded model for streptomycete circular plasmid transfer.
Ducote
Matthew J
MJ
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
Pettis
Gregg S
GS
D001426:Bacterial Proteins / Q000235:genetics; D003227:Conjugation, Genetic; D004261:DNA Replication; D004269:DNA, Bacterial; D010957:Plasmids / Q000235:genetics*; D011995:Recombination, Genetic; D013302:Streptomyces / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial