Restriction endonuclease mapping of R27 (TP117), an incompatibility group HI subgroup 1 plasmid from Salmonella typhimurium.

A circular map of the IncHI plasmid R27 corresponding to a genome size of 182 kb was established using the restriction endonucleases ApaI, XbaI, and PstI. The map was derived from the results obtained by hybridizing individual ApaI and XbaI fragments to blotted digests of the plasmid, as well as from complete and partial digests. Analysis of a deletion mutant derived by in vitro digestion with PstI and of transfer-defective and tetracycline-sensitive deletion mutants of R27 derived by Tn5 insertion were instrumental in determining the positions of some fragments.