Mapping of a plasmid, coding for colonization, factor antigen I and heat-stable enterotoxin production, isolated from an enterotoxigenic strain of Escherichia coli.

The non-autotransferring plasmid NTP113 codes for production of colonization factor antigen I and heat-stable enterotoxin, NTP113, which has a molecular weight of 58 X 10(6), was digested with BamHI, EcoRI, and HindIII and combinations of these restriction endonucleases, and the products of these digestions were analyzed by agarose gel electrophoresis. The results were used to construct a partial restriction map of NTP113. Transposons coding for resistance to ampicillin, kanamycin, and tetracycline were inserted into NTP113, and we obtained a series of deletion mutants, as determined by the loss of tetracycline or kanamycin resistance from strains carrying the insertion mutants. A number of plasmid mutants obtained by insertion or deletion did not code for colonization factor antigen I, but most of these mutants still coded for heat-stable enterotoxin production. The position of the inserted transposons and of the deletions were determined on the restriction map. Two regions of NTP113 were required for the expression of colonization factor antigen I, and the two sites were separated by a length of DNA corresponding to a molecular weight of about 25 X10(6).